Clinical Focus

  • Interventional Neuroradiology
  • Endovascular Neurosurgery
  • Cerebral aneurysm coiling
  • Brain AVM (arteriovenous malformation)
  • Stroke
  • Spinal Intervention for pain
  • Head and neck vascular malformations and anomalies
  • Interventional Oncology
  • Pediatric Neuroradiology
  • Vascular Malformations
  • Percutaneous Sclerotherapy
  • Vertebral compression fractures
  • Trigeminal Neuralgia and facial pain
  • Neuroradiology

Academic Appointments

  • Professor - University Medical Line, Radiology
  • Professor - University Medical Line (By courtesy), Neurosurgery
  • Professor - University Medical Line (By courtesy), Otolaryngology (Head and Neck Surgery)
  • Member, Bio-X

Administrative Appointments

  • Director, Interventional Neuroradiology Program Stanford University (2021 - Present)
  • Neuroradiology Fellowship Director, Stanford University School of Medicine (2004 - 2015)
  • Standards and Guidelines Committee, Society of Neurointerventional Surgery (2011 - 2015)
  • Senator, Stanford University School of Medicine Faculty Senate (2000 - 2011)
  • Executive Committee, Society of Neurointerventional Surgery (2002 - 2010)
  • Ad Hoc Awards Committee, American Society of Spine Radiology (2004 - 2008)
  • Technical Exhibit Committee, American Society of Neuroradiology (2010 - Present)
  • Fellowship Directors Committee, American Society of Neuroradiology (2004 - Present)

Honors & Awards

  • ASNR/Berlex Basic Science Research Fellow, American Society of Neuroradiology (1997-1998)
  • Executive Council Award, American Roentgen Ray Society (1999)
  • Cornelius G. Dyke Memorial Award, Co-investigator, American Society of Neuroradiology (2000)
  • General Electric/AUR Radiology Research Academic Fellowship, Association of University Radiologists (2000-2002)
  • Outstanding Presentation Award, American Society of Neuroradiology (2002)
  • Best Paper Presentation Award, American Society of Spine Radiology (2004)
  • ASSR Mentor Research Award, American Society of Spine Radiology (2003)
  • Michael Brothers Memorial Award, Co-investigator, American Society of Neuroradiology (2005)

Boards, Advisory Committees, Professional Organizations

  • Advisory Committe (Scientific Consultant), Food and Drug Administration (2011 - Present)
  • Board of Directors, Society of Neurointerventional Surgery (2002 - 2010)
  • Editorial Board, American Journal of Neuroradiology (2006 - 2008)
  • Editorial Board, Case Report in Medicine (2010 - Present)
  • Editorial Board, World Journal of Radiology (2013 - Present)

Professional Education

  • Fellowship, University of Virginia Health Sciences Center, Diagnostic and Interventional Neuroradiology (1999)
  • Board Certification: American Board of Radiology, Diagnostic Radiology (1996)
  • Residency: UCLA Radiology Residency (1996) CA
  • Internship: University of Washington Medical Center Dept of Medicine (1992) WA
  • Medical Education: Warren Alpert Medical School Brown University (1991) RI
  • Bachelor Degree, Brown University - Neural Sciences, RI (1988)

Clinical Trials

  • Ruptured Aneurysms Treated With Hydrogel Coils Recruiting

    To determine safety and occlusion rates when second-generation hydrogel coils are used in the treatment of ruptured intracranial aneurysms.

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  • Trametinib in the Treatment of Complicated Extracranial Arterial Venous Malformation Recruiting

    Arteriovenous malformation (AVM) is a congenital vascular anomaly that progresses throughout life and causes complications including tissue destruction due to rapid overgrowth, bleeding, functional deficits, severe deformity and cardiac failure. Unfortunately, traditional managements have transient benefits with more than 90 recurrence rate within a year. Therefore, there is a significant unmet medical need. The purpose of this study is to assess the safety and efficacy of Trametinib in children and adults with Extracranial Arteriovenous Malformation (AVM).

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  • A Randomized, Concurrent Controlled Trial to Assess the Safety and Effectiveness of the Separator 3D as a Component of the Penumbra System in the Revascularization of Large Vessel Occlusion in Acute Ischemic Stroke Not Recruiting

    This is a prospective, randomized, single blind, concurrent controlled, multi-center study. Patients presenting with symptoms of acute ischemic stroke who have evidence of a large vessel (2.5mm or greater in diameter) occlusion in the cerebral circulation will be assigned to either the Penumbra System with the Separator 3D or the Penumbra System without the Separator 3D. Each treated patient will be followed and assessed for 3 months after randomization. Up to 230 evaluable patients at up to 50 centers presenting with acute ischemic stroke in vessels accessible to the Penumbra Separator 3D System for revascularization within 8 hours of symptom onset. The hypothesis to be tested is that the safety and effectiveness of the Penumbra System with the Separator 3D for the revascularization of large vessel occlusion is not inferior to the Penumbra System alone.

    Stanford is currently not accepting patients for this trial. For more information, please contact Stephanie Kemp, (650) 723-4481 .

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  • ASSIST Registry Studying Various Operator Techniques Not Recruiting

    The purpose of this Registry is to assess the procedural success and clinical outcomes associated with various operator techniques for mechanical thrombectomy in large vessel occlusions (LVO).

    Stanford is currently not accepting patients for this trial.

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  • Computed Tomography Perfusion (CTP) to Predict Response to Recanalization in Ischemic Stroke Project (CRISP) Not Recruiting

    The overall goal of the CTP to predict Response to recanalization in Ischemic Stroke Project (CRISP) is to develop a practical tool to identify acute stroke patients who are likely to benefit from endovascular therapy. The project has two main parts. During the first part, the investigators propose to develop a fully automated system (RAPID) for processing of CT Perfusion (CTP) images that will generate brain maps of the ischemic core and penumbra. There will be no patient enrollment in part one of this project. During the second part, the investigators aim to demonstrate that physicians in the emergency setting, with the aid of a fully automated CTP analysis program (RAPID), can accurately predict response to recanalization in stroke patients undergoing revascularization. To achieve this aim the investigators will conduct a prospective cohort study of 240 consecutive stroke patients who will undergo a CTP scan prior to endovascular therapy. The study will be conducted at four sites (Stanford University, St Luke's Hospital, University of Pittsburgh Medical Center, and Emory University/Grady Hospital). Patients will have an early follow-up MRI scan within 12+/-6 hours to assess reperfusion and a late follow-up MRI scan at day 5 to determine the final infarct.

    Stanford is currently not accepting patients for this trial. For more information, please contact Stephanie M Kemp, BS, 650-723-4481.

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  • Evaluating Neuroprotection in Aneurysm Coiling Therapy Not Recruiting

    This is a randomized, double-blind, placebo-controlled, single-dose, design investigating the safety, tolerability and efficacy of NA-1, a peptide designed to reduce ischemic brain damage. Up to 200 male and female patients undergoing endovascular repair of brain aneurysm will be dosed with 2.60 mg/kg of NA-1 or placebo as a 10 minute intravenous infusion after completion of the endovascular procedure on Day 1 of the study period. Subjects will undergo interim procedures Days 2-4 and end-of study procedures on Day 30. Standard safety criteria will be analysed. Efficacy endpoints include the ability of NA-1 to: 1) reduce the volume of ischemic embolic strokes, 2) reduce the number of ischemic embolic strokes, 3) reduce vascular cognitive impairment, and 4) reduce the frequency of large strokes induced by the endovascular procedure. The plasma concentrations of NA-1 will also be analyzed.

    Stanford is currently not accepting patients for this trial. For more information, please contact Huy M. Do, MD, 650-723-6767.

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  • Phase I Trial of Arsenic Trioxide and Stereotactic Radiotherapy for Recurrent Malignant Glioma Not Recruiting

    To investigate the safety of delivering arsenic trioxide (ATO) in combination with stereotactic radiotherapy in recurrent malignant glioma by performing an open label, Phase I dose escalation trial. Results from this study will provide a basis for further study of ATO combined with radiation therapy as a radiosensitizer for malignant brain tumors in future Phase II studies.

    Stanford is currently not accepting patients for this trial. For more information, please contact Laurie Tupper, (650) 498 - 4143.

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  • PHIL in the Treatment of Intracranial dAVF. Not Recruiting

    This study is a prospective, multicenter, single-arm study. Patients with Dural Arteriovenous Fistulas (dAVF) have a few choice for safe treatment. In this study, all patients with qualifying dAVFs will be treated with PHIL® Liquid Embolic material.

    Stanford is currently not accepting patients for this trial.

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  • Protected Carotid Artery Stenting in Subjects at High Risk for Carotid Endarterectomy (CEA) (PROTECT) Not Recruiting

    The purpose of this study is to evaluate the long-term safety and efficacy of the Xact™ Rapid Exchange Carotid Stent System used in conjunction with the Emboshield® Pro Rapid Exchange Embolic Protection System (Generation 5) and the Emboshield® BareWire™ Rapid Exchange Embolic Protection System (Generation 3), in the treatment of atherosclerotic carotid artery disease in high-surgical risk subjects.

    Stanford is currently not accepting patients for this trial. For more information, please contact Ronald Dalman, (650) 725 - 5227.

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  • Quantifying Collateral Perfusion in Cerebrovascular Disease-Moyamoya Disease and Stroke Patients Not Recruiting

    Quantifying Collateral Perfusion in Cerebrovascular Disease-Moyamoya disease and stroke patients

    Stanford is currently not accepting patients for this trial. For more information, please contact Sandra Dunn, 650-724-8278.

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  • Safety and Effectiveness of an Intracranial Aneurysm Embolization System for Treating Large or Giant Wide Neck Aneurysms Not Recruiting

    This clinical research study is designed to determine safety and effectiveness of the Surpass Flow Diverter (Surpass System), an investigational device developed to treat wide-neck, large or giant intracranial aneurysms. An intracranial aneurysm is a bulge in the wall of a blood vessel in the brain. The bulge is caused by a weakening of the vessel wall. If left untreated, the bulge may continue to grow larger and ultimately the vessel may break open (rupture), resulting in serious bleeding into or around the brain. The information collected from this study will be used to evaluate how well patients do when treated with the Surpass System both immediately after treatment of an aneurysm and over a long period of time (5 years).

    Stanford is currently not accepting patients for this trial. For more information, please contact Kara Richardson, 650-736-6171.

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  • Sildenafil for the Treatment of Lymphatic Malformations Not Recruiting

    A Phase 2 study to evaluate safety and efficacy of sildenafil taken orally to improve or resolve lymphatic malformations in children. Subjects may receive either placebo or treatment in an oral dosage with an open label extension for subjects who received placebo. The study treatment assignment will be randomized in a double blind fashion. MRI examination will evaluate change in lesion volume due to treatment. Other safety and efficacy measures will be taken through the 32-week study duration. Funding Source - FDA OOPD

    Stanford is currently not accepting patients for this trial. For more information, please contact Elidia C Tafoya, MPH, 650-724-1982.

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2023-24 Courses

All Publications

  • Percutaneous Disc Biopsy versus Bone Biopsy for the Identification of Infectious Agents in Osteomyelitis/Discitis. Journal of vascular and interventional radiology : JVIR Zamarud, A., Kesten, J., Park, D. J., Pulli, B., Telischak, N. A., Dodd, R. L., Do, H. M., Marks, M. P., Heit, J. J. 2024


    To determine whether sampling of the disc or bone is more likely to yield positive tissue culture results in patients with vertebral discitis and osteomyelitis (VDO).Retrospective review was performed of consecutive patients who underwent vertebral disc or vertebral body biopsy at a single institution between February 2019 and May 2023. Inclusion criteria were age ≥18 years, presumed VDO on spinal magnetic resonance (MR) imaging, absence of paraspinal abscess, and technically successful percutaneous biopsy with fluoroscopic guidance. The primary outcome was a positive biopsy culture result, and secondary outcomes included complications such as nerve injury and segmental artery injury.Sixty-six patients met the inclusion criteria; 36 patients (55%) underwent disc biopsy, and 30 patients (45%) underwent bone biopsy. Six patients required a repeat biopsy for an initially negative culture result. No significant demographic, laboratory, antibiotic administration, or pain medication use differences were observed between the 2 groups. Patients who underwent bone biopsy were more likely to have a history of intravenous drug use (26.7%) compared with patients who underwent disc biopsy (5.5%; P = .017). Positive tissue culture results were observed in 41% of patients who underwent disc biopsy and 15% of patients who underwent bone biopsy (P = .016). No vessel or nerve injuries were detected after procedure in either group.Percutaneous disc biopsy is more likely to yield a positive tissue culture result than vertebral body biopsy in patients with VDO.

    View details for DOI 10.1016/j.jvir.2024.02.016

    View details for PubMedID 38613536

  • Mechanism of chronic iatrogenic CSF leak following dural puncture-ventral dural leak: case report. Regional anesthesia and pain medicine Carroll, I. R., Lansinger, O., Do, H. M., Dodd, R., Mahaney, K., Li, D. 2024


    BACKGROUND: Postdural puncture headache has been traditionally viewed as benign, self-limited, and highly responsive to epidural blood patching (EBP) when needed. A growing body of data from patients experiencing unintended dural puncture (UDP) in the setting of attempted labor epidural placement suggests a minority of patients will have more severe and persistent symptoms. However, the mechanisms accounting for the failure of EBP following dural puncture remain obscure. An understanding of these potential mechanisms is critical to guide management decisions in the face of severe and persistent cerebrospinal fluid (CSF) leak.CASE PRESENTATION: We report the case of a peripartum patient who developed a severe and persistent CSF leak unresponsive to multiple EBPs following a UDP during epidural catheter placement for labor analgesia. Lumbar MRI revealed a ventral rather than dorsal epidural fluid collection suggesting that the needle had crossed the thecal sac and punctured the ventral dura, creating a puncture site not readily accessible to blood injected in the dorsal epidural space. The location of this persistent ventral dural defect was confirmed with digital subtraction myelography, permitting a transdural surgical exploration and repair of the ventral dura with resolution of the severe intracranial hypotension.CONCLUSIONS: A ventral rather than dorsal dural puncture is one mechanism that may contribute to both severe and persistent spinal CSF leak with resulting intracranial hypotension following a UDP.

    View details for DOI 10.1136/rapm-2023-105197

    View details for PubMedID 38388018

  • Matched-pair analysis of patients with ischemic stroke undergoing thrombectomy using next-generation balloon guide catheters. Journal of neurointerventional surgery Kim, L. H., Choi, J., Zhou, J., Wolman, D., Pendharkar, A. V., Lansberg, M. G., Albers, G. W., Dodd, R., Do, H. M., Pulli, B., Heit, J. J., Telischak, N. A. 2023


    Balloon guide catheters (BGCs) have not been widely adopted, possibly due to the incompatibility of past-generation BGCs with large-bore intermediate catheters. The next-generation BGC is compatible with large-bore catheters. We compared outcomes of thrombectomy cases using BGCs versus conventional guide catheters.We conducted a retrospective study of 110 thrombectomy cases using BGCs (n=55) and non-BGCs (n=55). Sixty consecutive thrombectomy cases in whom the BOBBY BGC was used at a single institution between February 2021 and March 2022 were identified. Of these, 55 BGC cases were 1:1 matched with non-BGC cases by proceduralists, age, gender, stent retriever + aspiration device versus aspiration-only, and site of occlusion. First-pass effect was defined as Thrombolysis In Cerebral Infarction 2b or higher with a single pass.The BGC and non-BGC cohorts had similar mean age (67.2 vs 68.9 years), gender distribution (43.6% vs 47.3% women), median initial National Institutes of Health Stroke Scale score (14 vs 15), and median pretreatment ischemic core volumes (12 mL vs 11.5 mL). BGC and non-BGC cases had similar rates of single pass (60.0% vs 54.6%), first-pass effect (58.2% vs 49.1%), and complications (1.8% vs 9.1%). In aspiration-only cases, the BGC cohort had a significantly higher rate of first-pass effect (100% vs 50.0%, p=0.01). BGC was associated with a higher likelihood of achieving a modified Rankin Scale score of 2 at discharge (OR 7.76, p=0.02). No additional procedural time was required for BGC cases (46.7 vs 48.2 min).BGCs may be safely adopted with comparable procedural efficacy, benefits to aspiration-only techniques, and earlier functional improvement compared with conventional guide catheters.

    View details for DOI 10.1136/jnis-2023-020635

    View details for PubMedID 37793796

  • DEEP MOVEMENT: Deep learning of movie files for management of endovascular thrombectomy. European radiology Kelly, B., Martinez, M., Do, H., Hayden, J., Huang, Y., Yedavalli, V., Ho, C., Keane, P. A., Killeen, R., Lawlor, A., Moseley, M. E., Yeom, K. W., Lee, E. H. 2023


    OBJECTIVES: Treatment and outcomes of acute stroke have been revolutionised by mechanical thrombectomy. Deep learning has shown great promise in diagnostics but applications in video and interventional radiology lag behind. We aimed to develop a model that takes as input digital subtraction angiography (DSA) videos and classifies the video according to (1) the presence of large vessel occlusion (LVO), (2) the location of the occlusion, and (3) the efficacy of reperfusion.METHODS: All patients who underwent DSA for anterior circulation acute ischaemic stroke between 2012 and 2019 were included. Consecutive normal studies were included to balance classes. An external validation (EV) dataset was collected from another institution. The trained model was also used on DSA videos post mechanical thrombectomy to assess thrombectomy efficacy.RESULTS: In total, 1024 videos comprising 287 patients were included (44 for EV). Occlusion identification was achieved with 100% sensitivity and 91.67% specificity (EV 91.30% and 81.82%). Accuracy of location classification was 71% for ICA, 84% for M1, and 78% for M2 occlusions (EV 73, 25, and 50%). For post-thrombectomy DSA (n=194), the model identified successful reperfusion with 100%, 88%, and 35% for ICA, M1, and M2 occlusion (EV 89, 88, and 60%). The model could also perform classification of post-intervention videos as mTICI<3 with an AUC of 0.71.CONCLUSIONS: Our model can successfully identify normal DSA studies from those with LVO and classify thrombectomy outcome and solve a clinical radiology problem with two temporal elements (dynamic video and pre and post intervention).KEY POINTS: DEEP MOVEMENT represents a novel application of a model applied to acute stroke imaging to handle two types of temporal complexity, dynamic video and pre and post intervention. The model takes as an input digital subtraction angiograms of the anterior cerebral circulation and classifies according to (1) the presence or absence of large vessel occlusion, (2) the location of the occlusion, and (3) the efficacy of thrombectomy. Potential clinical utility lies in providing decision support via rapid interpretation (pre thrombectomy) and automated objective gradation of thrombectomy outcomes (post thrombectomy).

    View details for DOI 10.1007/s00330-023-09478-3

    View details for PubMedID 36847835

  • Automated detection of arterial landmarks and vascular occlusions in patients with acute stroke receiving digital subtraction angiography using deep learning. Journal of neurointerventional surgery Khankari, J., Yu, Y., Ouyang, J., Hussein, R., Do, H. M., Heit, J. J., Zaharchuk, G. 2022


    Digital subtraction angiography (DSA) is the gold-standard method of assessing arterial blood flow and blockages prior to endovascular thrombectomy.To detect anatomical features and arterial occlusions with DSA using artificial intelligence techniques.We included 82 patients with acute ischemic stroke who underwent DSA imaging and whose carotid terminus was visible in at least one run. Two neurointerventionalists labeled the carotid location (when visible) and vascular occlusions on 382 total individual DSA runs. For detecting the carotid terminus, positive and negative image patches (either containing or not containing the internal carotid artery terminus) were extracted in a 1:1 ratio. Two convolutional neural network architectures (ResNet-50 pretrained on ImageNet and ResNet-50 trained from scratch) were evaluated. Area under the curve (AUC) of the receiver operating characteristic and pixel distance from the ground truth were calculated. The same training and analysis methods were used for detecting arterial occlusions.The ResNet-50 trained from scratch most accurately detected the carotid terminus (AUC 0.998 (95% CI 0.997 to 0.999), p<0.00001) and arterial occlusions (AUC 0.973 (95% CI 0.971 to 0.975), p<0.0001). Average pixel distances from ground truth for carotid terminus and occlusion localization were 63±45 and 98±84, corresponding to approximately 1.26±0.90 cm and 1.96±1.68 cm for a standard angiographic field-of-view.These results may serve as an unbiased standard for clinical stroke trials, as optimal standardization would be useful for core laboratories in endovascular thrombectomy studies, and also expedite decision-making during DSA-based procedures.

    View details for DOI 10.1136/neurintsurg-2021-018638

    View details for PubMedID 35483913

  • Comparison of embolization strategies for mixed plexiform and fistulous brain arteriovenous malformations: a computational model analysis of theoretical risks of nidus rupture. Journal of neurointerventional surgery Jain, M. S., Telischak, N. A., Heit, J. J., Do, H. M., Massoud, T. F. 2021


    BACKGROUND: High-flow fistulas related to plexiform nidi are found in 40% of large brain arteriovenous malformations (AVMs). Endovascular occlusion of intranidal fistulas before plexiform components is empirically considered safe, but potential ensuing dangerous re-routing of flow through plexiform vessels may in theory raise their rupture risk. It remains unclear whether it is safer to embolize plexiform or fistulous vessels initially. We used a novel biomathematical AVM model to compare theoretical hemodynamic changes and rupture risks on sequential embolizations of both types of nidus vessels.METHODS: We computationally modeled a theoretical AVM as an electrical circuit containing a nidus consisting of a massive stochastic network ensemble comprising 1000 vessels. We sampled and individually simulated 10000 different nidus morphologies with a fistula angioarchitecturally isolated from its adjacent plexiform nidus. We used network analysis to calculate mean intravascular pressure (Pmean) and flow rate within each nidus vessel; and Monte Carlo analysis to assess overall risks of nidus rupture when simulating sequential occlusions of vessel types in all 10000 nidi.RESULTS: We consistently observed lower nidus rupture risks with initial fistula occlusion in different network morphologies. Intranidal fistula occlusion simultaneously reduced Pmean and flow rate within draining veins.CONCLUSIONS: Initial occlusion of AVM fistulas theoretically reduces downstream draining vessel hypertension and lowers the risk of rupture of an adjoining plexiform nidus component. This mitigates the theoretical concern that fistula occlusion may cause dangerous redistribution of hemodynamic forces into plexiform nidus vessels, and supports a clinical strategy favoring AVM fistula occlusion before plexiform nidus embolization.

    View details for DOI 10.1136/neurintsurg-2021-018067

    View details for PubMedID 34893533

  • Arteriovenous Malformations-Current Understanding of the Pathogenesis with Implications for Treatment. International journal of molecular sciences Schimmel, K., Ali, M. K., Tan, S. Y., Teng, J., Do, H. M., Steinberg, G. K., Stevenson, D. A., Spiekerkoetter, E. 2021; 22 (16)


    Arteriovenous malformations are a vascular anomaly typically present at birth, characterized by an abnormal connection between an artery and a vein (bypassing the capillaries). These high flow lesions can vary in size and location. Therapeutic approaches are limited, and AVMs can cause significant morbidity and mortality. Here, we describe our current understanding of the pathogenesis of arteriovenous malformations based on preclinical and clinical findings. We discuss past and present accomplishments and challenges in the field and identify research gaps that need to be filled for the successful development of therapeutic strategies in the future.

    View details for DOI 10.3390/ijms22169037

    View details for PubMedID 34445743

  • Radiosurgery as a microsurgical adjunct: outcomes after microsurgical resection of intracranial arteriovenous malformations previously treated with stereotactic radiosurgery. Journal of neurosurgery Bigder, M., Choudhri, O., Gupta, M., Gummidipundi, S., Han, S. S., Church, E. W., Chang, S. D., Levy, R. P., Do, H. M., Marks, M. P., Steinberg, G. K. 2021: 1-12


    OBJECTIVE: Microsurgical resection of arteriovenous malformations (AVMs) can be aided by staged treatment consisting of stereotactic radiosurgery followed by resection in a delayed fashion. This approach is particularly useful for high Spetzler-Martin (SM) grade lesions because radiosurgery can reduce flow through the AVM, downgrade the SM rating, and induce histopathological changes that additively render the AVM more manageable for resection. The authors present their 28-year experience in managing AVMs with adjunctive radiosurgery followed by resection.METHODS: The authors retrospectively reviewed records of patients treated for cerebral AVMs at their institution between January 1990 and August 2019. All patients who underwent stereotactic radiosurgery (with or without embolization), followed by resection, were included in the study. Of 1245 patients, 95 met the eligibility criteria. Univariate and multivariate regression analyses were performed to assess relationships between key variables and clinical outcomes.RESULTS: The majority of lesions treated (53.9%) were high grade (SM grade IV-V), 31.5% were intermediate (SM grade III), and 16.6% were low grade (SM grade I-II). Hemorrhage was the initial presenting sign in half of all patients (49.5%). Complete resection was achieved among 84% of patients, whereas 16% had partial resection, the majority of whom received additional radiosurgery. Modified Rankin Scale (mRS) scores of 0-2 were achieved in 79.8% of patients, and 20.2% had poor (mRS scores 3-6) outcomes. Improved (44.8%) or stable (19%) mRS scores were observed among 63.8% of patients, whereas 36.2% had a decline in mRS scores. This includes 22 patients (23.4%) with AVM hemorrhage and 6 deaths (6.7%) outside the perioperative period but prior to AVM obliteration.CONCLUSIONS: Stereotactic radiosurgery is a useful adjunct in the presurgical management of cerebral AVMs. Multimodal therapy allowed for high rates of AVM obliteration and acceptable morbidity rates, despite the predominance of high-grade lesions in this series of patients.

    View details for DOI 10.3171/2020.9.JNS201538

    View details for PubMedID 34116503

  • Genome Sequencing and Apoptotic Markers to Assess Treatment Response of Lacrimal Gland Adenoid Cystic Carcinoma to Intra-Arterial Cytoreductive Chemotherapy. Ophthalmic plastic and reconstructive surgery Yu, M. D., Men, C. J., Do, H., Colevas, A. D., Lin, J. H., Egbert, P. R., Tse, D. T., Kossler, A. L. 2021


    Adenoid cystic carcinoma of the lacrimal gland is an aggressive, malignant epithelial neoplasm. We report the case of a 30-year-old male with lacrimal gland adenoid cystic carcinoma treated with neoadjuvant intra-arterial chemotherapy through the internal carotid artery, followed by orbital exenteration and chemoradiation. Treatment response was evaluated using a novel combination of pre- and posttreatment genome sequencing coupled with immunohistochemical evaluation, which showed diffuse tumor apoptosis. A posttreatment decrease in variant allele frequency of the NOTCH1 mutation, and robust tumor cytoreduction on imaging, supports exploration of NOTCH1 analysis as a potential marker of cisplatin sensitivity. The use of genome sequencing and immunohistochemical evaluation could provide a more targeted therapeutic assessment of neoadjuvant intra-arterial chemotherapy in the management of lacrimal gland adenoid cystic carcinoma.

    View details for DOI 10.1097/IOP.0000000000002079

    View details for PubMedID 34798653

  • Efficacy and Safety of Awake CT-guided Percutaneous Balloon Compression of Trigeminal Ganglion for Trigeminal Neuralgia. Pain medicine (Malden, Mass.) Huang, B., Yao, M., Chen, Q., Du, X., Li, Z., Xie, K., Fei, Y., Do, H., Qian, X. 2021


    To describe the method and clinical efficacy of awake CT-guided percutaneous balloon compression (PBC) as a treatment for trigeminal neuralgia (TN).In this case-series, TN patients were treated with awake CT-guided PBC and followed for treatment efficacy and complications for 12 months.A single-center study.66 patients with medical treatment-refractory TN were recruited for the study.The procedure was performed under moderate sedation. A balloon catheter was inserted through a trocar needle to reach Meckel's cavity under CT-guidance. The position and optimal shape of the contrast-filled balloon was confirmed with CT 3-dimension reconstruction. Compression of the TG was considered completed when the patient notified operators about facial hypoesthesia or the resolution of TN symptoms. All patients were followed up monthly for 12 months to monitor treatment efficacy and complications.The average TG compression time was 272±81 seconds, at which point the patients reported significant facial hypoesthesia comparing to the contralateral side or resolution of triggered pain in the affected area. All patients had resolution of TN symptoms for 6 months, with a 1-year recurrent rate of 13%. Overall safety profile is improved with the current technique. Side effects, such as hypoesthesia, and mastication weakness, were overall mild, and did not impact patients' quality-of-life. Some complications that were historically associated with PBC, such as diplopia and keratitis, were not present.This new awake CT-guided PBC technique produces better outcomes than the traditional PBC under fluoroscopy-guidance and general anesthesia.

    View details for DOI 10.1093/pm/pnab228

    View details for PubMedID 34320638

  • Awake CT-guided percutaneous stylomastoid foramen puncture and radiofrequency ablation of facial nerve for treatment of hemifacial spasm. Journal of neurosurgery Huang, B. n., Yao, M. n., Chen, Q. n., Lin, H. n., Du, X. n., Huang, H. n., Zhao, X. n., Do, H. n., Qian, X. n. 2021: 1–7


    Hemifacial spasm (HFS) is a debilitating neuromuscular disorder with limited treatment options. The current study describes a novel minimally invasive procedure that provided effective and sustained relief for patients with HFS. The authors provide a detailed description of the awake CT-guided percutaneous radiofrequency ablation (RFA) of the facial nerve for treatment of HFS, and they examine its clinical efficacy. This is the first time in the literature that this procedure has been applied and systematically analyzed for HFS.Patients with a history of HFS were recruited between August 2018 and April 2020. Those with a history of cerebellopontine lesions, coagulopathy, ongoing pregnancy, cardiac pacemaker or defibrillator implants, or who declined the procedure were excluded from the study. Fifty-three patients who met the study criteria were included and underwent awake CT-guided RFA. Under minimal sedation, a radiofrequency (RF) needle was used to reach the stylomastoid foramen on the affected side under CT guidance, and the facial nerve was localized using a low-frequency stimulation current. Patients were instructed to engage facial muscles as a proxy for motor monitoring during RFA. Ablation stopped when the patients' hemifacial contracture resolved. Patients were kept for inpatient monitoring for 24 hours postoperatively and were followed up monthly to monitor resolution of HFS and complications for up to 19 months.The average duration of the procedure was 32-34 minutes. Postoperatively, 91% of the patients (48/53) had complete resolution of HFS, whereas the remaining individuals had partial resolution. A total of 48 patients reported mild to moderate facial paralysis immediately post-RFA, but most resolved within 1 month. No other significant complication was observed during the study period. By the end of the study period, 5 patients had recurrence of mild HFS symptoms, whereas only 2 patients reported dissatisfaction with the treatment results.The authors report for the first time that awake CT-guided RFA of the facial nerve at the stylomastoid foramen is a minimally invasive procedure and can be an effective treatment option for HFS.

    View details for DOI 10.3171/2020.10.JNS203209

    View details for PubMedID 33862595

  • Efficacy and safety of embolization of dural arteriovenous fistulas via the ophthalmic artery. Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences Mayercik, V. A., Sussman, E. S., Pulli, B., Dodd, R. L., Do, H. M., Telischak, N. A., Marks, M. P., Steinberg, G. K., Chang, S. D., Heit, J. J. 2020: 1591019920969270


    INTRODUCTION: Dural arteriovenous fistulae (DAVF) are vascular lesions with arteriovenous shunting that may be treated with surgical obliteration or endovascular embolization. Some DAVF, such as anterior cranial fossa DAVF (AC-DAVF) derive their arterial supply from ophthalmic artery branches in nearly all cases, and trans-arterial embolization carries a risk of vision loss. We determined the efficacy and safety of trans-ophthalmic artery embolization of DAVF.MATERIALS AND METHODS: We performed a retrospective cohort study of all patients with DAVF treated by trans-ophthalmic artery embolization from 2012 to 2020. Primary outcome was angiographic cure of the DAVF. Secondary outcomes included vision loss, visual impairment, orbital cranial nerve injury, stroke, modified Rankin Scale at 90-days, and mortality.RESULTS: 12 patients met inclusion criteria (9 males; 3 females). 10 patients had AC-DAVF. Patient age was 59.7±9.5 (mean±SD) years. Patients presented with intracranial hemorrhage (4 patients), headache (4 patients), amaurosis fugax (1 patients), or were incidentally discovered (2 patients). DAVF Cognard grades were: II (1 patient), III (6 patients), and IV (5 patients). DAVF were embolized with Onyx (10 patients), nBCA glue (1 patient), and a combination of coils and Onyx (1 patient). DAVF cure was achieved in 11 patients (92%). No patients experienced vision loss, death, or permanent disability. One patient experienced a minor complication of blurry vision attributed to posterior ischemic optic neuropathy. 90-day mRS was 0 (10 patients) and 1 (2 patients).CONCLUSIONS: Trans-ophthalmic artery embolization is an effective and safe treatment for DAVF.

    View details for DOI 10.1177/1591019920969270

    View details for PubMedID 33106085

  • Treatment of posterior circulation fusiform aneurysms. Journal of neurosurgery Church, E. W., Bigder, M. G., Sussman, E. S., Gummidipundi, S. E., Han, S. S., Heit, J. J., Do, H. M., Dodd, R. L., Marks, M. P., Steinberg, G. K. 2020: 1–7


    OBJECTIVE: Perforator arteries, the absence of an aneurysm discrete neck, and the often-extensive nature of posterior circulation fusiform aneurysms present treatment challenges. There have been advances in microsurgical and endovascular approaches, including flow diversion, and the authors sought to review these treatments in a long-term series at their neurovascular referral center.METHODS: The authors performed a retrospective chart review from 1990 to 2018. Primary outcomes were modified Rankin Scale (mRS) scores and Glasgow Outcome Scale (GOS) scores at follow-up. The authors also examined neurological complication rates. Using regression techniques, they reviewed independent and dependent variables, including presenting features, aneurysm location and size, surgical approach, and pretreatment and posttreatment thrombosis.RESULTS: Eighty-four patients met the inclusion criteria. Their mean age was 53 years, and 49 (58%) were female. Forty-one (49%) patients presented with subarachnoid hemorrhage. Aneurysms were located on the vertebral artery (VA) or posterior inferior cerebellar artery (PICA) in 50 (60%) patients, basilar artery (BA) or vertebrobasilar junction (VBJ) in 22 (26%), and posterior cerebral artery (PCA) in 12 (14%). Thirty-one (37%) patients were treated with microsurgical and 53 (63%) with endovascular approaches. Six aneurysms were treated with endovascular flow diversion. The authors found moderate disability or better (mRS score ≤ 3) in 85% of the patients at a mean 14-month follow-up. The GOS score was ≥ 4 in 82% of the patients. The overall neurological complication rate was 12%. In the regression analysis, patients with VA or PICA aneurysms had better functional outcomes than the other groups (p < 0.001). Endovascular strategies were associated with better outcomes for BA-VBJ aneurysms (p < 0.01), but microsurgery was associated with better outcomes for VA-PICA and PCA aneurysms (p < 0.05). There were no other significant associations between patient, aneurysm characteristics, or treatment features and neurological complications (p > 0.05). Patients treated with flow diversion had more complications than those who underwent other endovascular and microsurgical strategies, but the difference was not significant in regression models.CONCLUSIONS: Posterior circulation fusiform aneurysms remain a challenging aneurysm subtype, but an interdisciplinary treatment approach can result in good outcomes. While flow diversion is a useful addition to the armamentarium, traditional endovascular and microsurgical techniques continue to offer effective options.

    View details for DOI 10.3171/2020.4.JNS192838

    View details for PubMedID 32707547

  • Endovascular Treatment of Acute Carotid Stent Occlusion: Aspiration Thrombectomy and Angioplasty CUREUS Murray, N. M., Wolman, D. N., Marks, M., Dodd, R., Do, H. M., Lee, J. T., Heit, J. J. 2020; 12 (5)
  • Endovascular Treatment of Acute Carotid Stent Occlusion: Aspiration Thrombectomy and Angioplasty. Cureus Murray, N. M., Wolman, D. N., Marks, M., Dodd, R., Do, H. M., Lee, J. T., Heit, J. J. 2020; 12 (5): e7997


    Introduction Acute carotid stent occlusion (CSO) is a rare complication of endovascular carotid stent placement that requires emergent intervention. We describe angioplasty or combined angioplasty and aspiration thrombectomy as a new endovascular technique for CSO treatment. The technique is compared to others previously described in the literature. Methods We performed a retrospective cohort study of all patients who underwent endovascular treatment (ET) of acute symptomatic CSO from January 2008 to March 2018 at our neurovascular referral center. Patient demographics, endovascular treatment details, and outcome data were determined from the electronic medical record. Primary outcome was successful stent recanalization and cerebral reperfusion (modified thrombolysis in cerebral infarction (mTICI) score IIB-III). Secondary outcomes were National Institutes of Health Stroke Scale (NIHSS) shift from presentation to discharge, mortality, and modified Rankin Scale (mRS) score at 3 months. Additionally, a literature review (years 2008-2019) was performed to characterize other techniques for ET of CSO. Results Four patients who underwent ET of acute CSO were identified. ET treatment by angioplasty (n = 1) or combined aspiration thrombectomy and angioplasty (n = 3) resulted in carotid stent recanalization in all patients. Tandem intracranial occlusions were present in three patients (75%), and successful cerebral reperfusion was achieved in all patients. Patient symptoms improved (mean NIHSS shift -5.3 ± 7.2 at discharge). One patient died of a symptomatic reperfusion hemorrhage and another died of cardiac complications by 3-month follow-up. The mRS scores of the surviving patients were 1 and 3. Previously described studies (n = 14) using different and varied techniques had moderate recanalization rates and outcomes. Conclusion Combined aspiration thrombectomy and angioplasty for the neurointerventional treatment of acute CSO leads to high rates of stent recanalization and cerebral reperfusion. The recanalization rate here is improved compared to previously reported techniques. Further multicenter studies are required to risk-stratify patients for specific ET interventions.

    View details for DOI 10.7759/cureus.7997

    View details for PubMedID 32523851

    View details for PubMedCentralID PMC7274505

  • Validation and Application for the Berlin Grading System of Moyamoya Disease in Adult Patients NEUROSURGERY Teo, M., Furtado, S., Kaneko, O. F., Azad, T. D., Madhugiri, V., Do, H. M., Steinberg, G. K. 2020; 86 (2): 203–11
  • Longitudinal alteration of cortical thickness and volume in high-impact sports. NeuroImage Mills, B. D., Goubran, M. n., Parivash, S. N., Dennis, E. L., Rezaii, P. n., Akers, C. n., Bian, W. n., Mitchell, L. A., Boldt, B. n., Douglas, D. n., Sami, S. n., Mouchawar, N. n., Wilson, E. W., DiGiacomo, P. n., Parekh, M. n., Do, H. n., Lopez, J. n., Rosenberg, J. n., Camarillo, D. n., Grant, G. n., Wintermark, M. n., Zeineh, M. n. 2020: 116864


    Collegiate football athletes are subject to repeated head impacts. The purpose of this study was to determine whether this exposure can lead to changes in brain structure. This prospective cohort study was conducted with up to 4 years of follow-up on 63 football (high-impact) and 34 volleyball (control) male collegiate athletes with a total of 315 MRI scans (after exclusions: football n=50, volleyball n= 24, total scans=273) using high-resolution structural imaging. Volumetric and cortical thickness estimates were derived using FreeSurfer 5.3's longitudinal pipeline. A linear mixed-effects model assessed the effect of group (football vs. volleyball), time from baseline MRI, and the interaction between group and time. We confirmed an expected developmental decrement in cortical thickness and volume in our cohort (p<0.001). Superimposed on this, total cortical gray matter volume (p = .03) and cortical thickness within the left hemisphere (p=.04) showed a group by time interaction, indicating less age-related volume reduction and thinning in football compared to volleyball athletes. At the regional level, sport by time interactions on thickness and volume were identified in the left orbitofrontal (p=.001), superior temporal (p=.001), and postcentral regions (p< .001). Additional cortical thickness interactions were found in the left temporal pole (p=.003) and cuneus (p=.005). At the regional level, we also found main effects of sport in football athletes characterized by reduced volume in the right hippocampus (p=.003), right superior parietal cortical gray (p<.001) and white matter (p<.001), and increased volume of the left pallidum (p=.002). Within football, cortical thickness was higher with greater years of prior play (left hemisphere p=.013, right hemisphere p=.005), and any history of concussion was associated with less cortical thinning (left hemisphere p=.010, right hemisphere p=.011). Additionally, both position-associated concussion risk (p=.002) and SCAT scores (p=.023) were associated with less of the expected volume decrement of deep gray structures. This prospective longitudinal study comparing football and volleyball athletes shows divergent age-related trajectories of cortical thinning, possibly reflecting an impact-related alteration of normal cortical development. This warrants future research into the underlying mechanisms of impacts to the head on cortical maturation.

    View details for DOI 10.1016/j.neuroimage.2020.116864

    View details for PubMedID 32360690

  • Initial experience with the Scepter Mini dual-lumen balloon for transophthalmic artery embolization of anterior cranial fossa dural arteriovenous fistulae. Journal of neurointerventional surgery Pulli, B. n., Sussman, E. S., Mayercik, V. n., Steinberg, G. K., Do, H. M., Heit, J. J. 2020


    Precise delivery of liquid embolic agents (LEAs) remains a challenge in the endovascular treatment of dural arteriovenous fistulae (dAVFs) and cerebral arteriovenous malformations (cAVMs). Despite significant advances in the past decade, LEA reflux and catheter navigability remain shortcomings of current endovascular technology, particularly in small and tortuous arteries. The Scepter Mini dual-lumen balloon microcatheter aims to address these issues by decreasing the distal catheter profile (1.6 French) while allowing for a small (2.2 mm diameter) balloon at its tip.We report our initial experience with the Scepter Mini in two patients with anterior cranial fossa dAVFs that were treated with transophthalmic artery embolization.In both patients, the Scepter Mini catheter was able to be safely advanced into the distal ophthalmic artery close to the fistula site, and several centimeters past the origins of the central retinal and posterior ciliary arteries. A single Onyx injection without any reflux resulted in angiographic cure of the dAVF in both cases, and neither patient suffered any vision loss.These initial experiences suggest that the Scepter Mini represents a significant advance in the endovascular treatment of dAVFs and cAVMs and will allow for safer and more efficacious delivery of LEAs into smaller and more distal arteries while diminishing the risk of LEA reflux.

    View details for DOI 10.1136/neurintsurg-2020-016013

    View details for PubMedID 32434799

  • Computational Network Modeling of Intranidal Hemodynamic Compartmentalization in a Theoretical Three-Dimensional Brain Arteriovenous Malformation. Frontiers in physiology Jain, M. S., Do, H. M., Massoud, T. F. 2019; 10: 1250


    There are currently no in vivo techniques to accurately study dynamic equilibrium of blood flow within separate regions (compartments) of a large brain arteriovenous malformation (AVM) nidus. A greater understanding of this AVM compartmentalization, even if theoretical, would be useful for optimal planning of endovascular and multimodal AVM therapies. We aimed to develop a biomathematical AVM model for theoretical investigations of intranidal regions of increased mean intravascular pressure (Pmean) and flow representing hemodynamic compartments, upon simulated AVM superselective angiography (SSA). We constructed an AVM model as a theoretical electrical circuit containing four arterial feeders (AF1-AF4) and a three-dimensional nidus of 97 interconnected plexiform and fistulous components. We simulated SSA by increases in Pmean in each AF (with and without occlusion of all other AFs), and then used network analysis to establish resulting increases in Pmean and flow within each nidus vessel. We analyzed shifts in hemodynamic compartments consequent to increasing AF injection pressures. SSA simulated by increases of 10 mm Hg in AF1, AF2, AF3, or AF4 resulted in dissipation of Pmean over 38, 66, 76, or 20% of the nidus, respectively, rising slightly with simultaneous occlusion of other AFs. We qualitatively analyzed shifting intranidal compartments consequent to varying injection pressures by mapping the hemodynamic changes onto the nidus network. Differences in extent of nidus filling upon SSA injections provide theoretical evidence that hemodynamic and angioarchitectural features help establish AVM nidus compartmentalization. This model based on a theoretical AVM will serve as a useful computational tool for further investigations of AVM embolotherapy strategies.

    View details for DOI 10.3389/fphys.2019.01250

    View details for PubMedID 31607956

    View details for PubMedCentralID PMC6769414

  • Computational Network Modeling of Intranidal Hemodynamic Compartmentalization in a Theoretical Three-Dimensional Brain Arteriovenous Malformation FRONTIERS IN PHYSIOLOGY Jain, M. S., Do, H. M., Massoud, T. F. 2019; 10
  • Neuroimaging selection for thrombectomy in pediatric stroke: a single-center experience JOURNAL OF NEUROINTERVENTIONAL SURGERY Lee, S., Heit, J., Albers, G. W., Wintermark, M., Jiang, B., Bernier, E., Fischbein, N. J., Mlynash, M., Marks, M. P., Do, H. M., Dodd, R. L. 2019; 11 (9): 940–46
  • Endovascular versus medical therapy for large-vessel anterior occlusive stroke presenting with mild symptoms. International journal of stroke : official journal of the International Stroke Society Wolman, D. N., Marcellus, D. G., Lansberg, M. G., Albers, G., Guenego, A., Marks, M. P., Dodd, R. L., Do, H. M., Wintermark, M., Martin, B. W., Heit, J. J. 2019: 1747493019873510


    BACKGROUND: Acute ischemic stroke patients with a large-vessel occlusion but mild symptoms (NIHSS≤6) pose a treatment dilemma between medical management and endovascular thrombectomy.AIMS: To evaluate the differences in clinical outcomes of endovascular thrombectomy-eligible patients with target-mismatch perfusion profiles who undergo either medical management or endovascular thrombectomy.METHODS: Forty-seven patients with acute ischemic stroke due to large-vessel occlusion, NIHSS≤6, and a target-mismatch perfusion imaging profile were included. Patients underwent medical management or endovascular thrombectomy following treating neurointerventionalist and neurologist consensus. The primary outcome measure was NIHSS shift. Secondary outcome measures were symptomatic intracranial hemorrhage, in-hospital mortality, and 90-day mRS scores. The primary intention-to-treat and as-treated analyses were compared to determine the impact of crossover patient allocation on study outcome measures.RESULTS: Forty-seven patients were included. Thirty underwent medical management (64%) and 17 underwent endovascular thrombectomy (36%). Three medical management patients underwent endovascular thrombectomy due to early clinical deterioration. Presentation NIHSS (P=0.82), NIHSS shift (P=0.62), and 90-day functional independence (mRS 0-2; P=0.25) were similar between groups. Endovascular thrombectomy patients demonstrated an increased overall rate of intracranial hemorrhage (35.3% vs. 10.0%; P=0.04), but symptomatic intracranial hemorrhage was similar between groups (P=0.25). In-hospital mortality was similar between groups (P=0.46), though all two deaths in the medical management group occurred among crossover patients. Endovascular thrombectomy patients demonstrated a longer length of stay (7.6±7.2 vs. 4.3±3.9 days; P=0.04) and a higher frequency of unfavorable discharge to a skilled-nursing facility (P=0.03) rather than home (P=0.05).CONCLUSIONS: Endovascular thrombectomy may pose an unfavorable risk-benefit profile over medical management for endovascular thrombectomy-eligible acute ischemic stroke patients with mild symptoms, which warrants a randomized trial in this subpopulation.

    View details for DOI 10.1177/1747493019873510

    View details for PubMedID 31474193

  • Multimodal management of arteriovenous malformations of the basal ganglia and thalamus: factors affecting obliteration and outcome JOURNAL OF NEUROSURGERY Madhugiri, V. S., Teo, M. C., Westbroek, E. M., Chang, S. D., Marks, M. P., Do, H. M., Levy, R. P., Steinberg, G. K. 2019; 131 (2): 410–19
  • Longitudinal Changes in Hippocampal Subfield Volume Associated with Collegiate Football JOURNAL OF NEUROTRAUMA Parivash, S. N., Goubran, M., Mills, B. D., Rezaii, P., Thaler, C., Wolman, D., Bian, W., Mitchell, L. A., Boldt, B., Douglas, D., Wilson, E. W., Choi, J., Xie, L., Yushkevich, P. A., DiGiacomo, P., Wongsripuemtet, J., Parekh, M., Fiehler, J., Do, H., Lopez, J., Rosenberg, J., Camarillo, D., Grant, G., Wintermark, M., Zeineh, M. 2019
  • Surgical Treatment of Recurrent Previously Coiled and/or Stent-Coiled Intracerebral Aneurysms: A Single-Center Experience in a Series of 75 Patients WORLD NEUROSURGERY Liu, J. J., Nielsen, T. H., Abhinav, K., Lee, J., Han, S. S., Marks, M. P., Do, H. M., Dodd, R. L., Steinberg, G. K. 2019; 124: E649–E658
  • Validation and Application for the Berlin Grading System of Moyamoya Disease in Adult Patients. Neurosurgery Teo, M., Furtado, S., Kaneko, O. F., Azad, T. D., Madhugiri, V., Do, H. M., Steinberg, G. K. 2019


    BACKGROUND: Traditional moyamoya disease (MMD) classification relies on morphological digital subtraction angiography (DSA) assessment, which do not reflect hemodynamic status, clinical symptoms, or surgical treatment outcome.OBJECTIVE: To (1) validate the new Berlin MMD preoperative symptomatology grading system and (2) determine the clinical application of the grading system in predicting radiological and clinical outcomes after surgical revascularization.METHODS: Ninety-six MMD patients (192 hemispheres) with all 3 investigations (DSA, magnetic resonance imaging [MRI], Xenon-CT) performed preoperatively at our institution (2007-2013) were included. Two clinicians independently graded the imaging findings according to the proposed criteria. Patients' modified Rankin Score (mRS) scores (preoperative, postoperative, last follow-up), postoperative infarct (radiological, clinical) were collected and statistical correlations performed.RESULTS: One hundred fifty-seven direct superficial temporal artery-middle cerebral artery bypasses were performed on 96 patients (66 female, mean age 41 yr, mean follow-up 4.3 yr). DSA, MRI, and cerebrovascular reserve capacity were independent factors associated hemispheric symptomatology (when analyzed individually or in the combined grading system). Mild (grade I), moderate (grade II), severe (grade III) were graded in 45, 71, and 76 hemispheres respectively; of which, clinical symptoms were found in 33% of grade I, 92% of grade II, 100% of grade III hemispheres (P<.0001). Two percent of grade I, 11% of grade II, 20% of grade III hemispheres showed postoperative radiological diffusion weighted image-positive ischemic changes or hemorrhage on MRI (P=.018). Clinical postoperative stroke was observed in 1.4% of grade II, 6.6% of grade III hemispheres (P=.077). The grading system also correlated well to dichotomized mRS postoperative outcome.CONCLUSION: The Berlin MMD grading system is able to stratify preoperative hemispheric symptomatology. Furthermore, it correlated with postoperative new ischemic changes on MRI, and showed a strong trend in predicting clinical postoperative stroke.

    View details for PubMedID 30864668

  • Large-scale ensemble simulations of biomathematical brain arteriovenous malformation models using graphics processing unit computation. Computers in biology and medicine Jain, M. S., Do, H. M., Wintermark, M. n., Massoud, T. F. 2019; 113: 103416


    Theoretical modeling allows investigations of cerebral arteriovenous malformation (AVM) hemodynamics, but current models are too simple and not clinically representative. We developed a more realistic AVM model based on graphics processing unit (GPU) computing, to replicate highly variable and complex nidus angioarchitectures with vessel counts in the thousands-orders of magnitude greater than current models.We constructed a theoretical electrical circuit AVM model with a nidus described by a stochastic block model (SBM) of 57 nodes and an average of 1000 plexiform and fistulous vessels. We sampled and individually simulated 10,000 distinct nidus morphologies from this SBM, constituting an ensemble simulation. We assigned appropriate biophysical values to all model vessels, and known values of mean intravascular pressure (Pmean) to extranidal vessels. We then used network analysis to calculate Pmean and volumetric flow rate within each nidus vessel, and mapped these values onto a graphic representation of the nidus network. We derived an expression for nidus rupture risk and conducted a model parameter sensitivity analysis.Simulations revealed a total intranidal volumetric blood flow ranging from 268 mL/min to 535 mL/min, with an average of 463 mL/min. The maximum percentage rupture risk among all vessels in the nidus ranged from 0% to 60%, with an average of 29%.This easy to implement biomathematical AVM model, allowed by parallel data processing using advanced GPU computing, will serve as a useful tool for theoretical investigations of AVM therapies and their hemodynamic sequelae.

    View details for DOI 10.1016/j.compbiomed.2019.103416

    View details for PubMedID 31494430

  • Neuroimaging selection for thrombectomy in pediatric stroke: a single-center experience. Journal of neurointerventional surgery Lee, S. n., Heit, J. J., Albers, G. W., Wintermark, M. n., Jiang, B. n., Bernier, E. n., Fischbein, N. J., Mlynash, M. n., Marks, M. P., Do, H. M., Dodd, R. L. 2019


    The extended time window for endovascular therapy in adult stroke represents an opportunity for stroke treatment in children for whom diagnosis may be delayed. However, selection criteria for pediatric thrombectomy has not been defined.We performed a retrospective cohort study of patients aged <18 years presenting within 24 hours of acute large vessel occlusion. Patient consent was waived by our institutional IRB. Patient data derived from our institutional stroke database was compared between patients with good and poor outcome using Fisher's exact test, t-test, or Mann-Whitney U-test.Twelve children were included: 8/12 (66.7%) were female, mean age 9.7±5.0 years, median National Institutes of Health Stroke Scale (NIHSS) 11.5 (IQR 10-14). Stroke etiology was cardioembolic in 75%, dissection in 16.7%, and cryptogenic in 8.3%. For 2/5 with perfusion imaging, Tmax >4 s appeared to better correlate with NIHSS. Nine patients (75%) were treated: seven underwent thrombectomy alone; one received IV alteplase and thrombectomy, and one received IV alteplase alone. Favorable outcome was achieved in 78% of treated patients versus 0% of untreated patients (P=0.018). All untreated patients had poor outcome, with death (n=2) or severe disability (n=1) at follow-up. Among treated patients, older children (12.8±2.9 vs 4.2±5.0 years, P=0.014) and children presenting as outpatient (100% vs 0%, P=0.028) appeared to have better outcomes.Perfusion imaging is feasible in pediatric stroke and may help identify salvageable tissue in extended time windows, though penumbral thresholds may differ from adult values. Further studies are needed to define criteria for thrombectomy in this unique population.

    View details for PubMedID 31097548

  • Thrombectomy for acute ischemic stroke in nonagenarians compared with octogenarians. Journal of neurointerventional surgery Sussman, E. S., Martin, B. n., Mlynash, M. n., Marks, M. P., Marcellus, D. n., Albers, G. n., Lansberg, M. n., Dodd, R. n., Do, H. M., Heit, J. J. 2019


    Multiple randomized trials have shown that endovascular thrombectomy (EVT) leads to improved outcomes in acute ischemic stroke (AIS) due to large vessel occlusion (LVO). Elderly patients were poorly represented in these trials, and the efficacy of EVT in nonagenarian patients remains uncertain.We performed a retrospective cohort study at a single center. Inclusion criteria were: age 80-99, LVO, core infarct <70 mL, and salvageable penumbra. Patients were stratified into octogenarian (80-89) and nonagenarian (90-99) cohorts. The primary outcome was the ordinal score on the modified Rankin Scale (mRS) at 90 days. Secondary outcomes included dichotomized functional outcome (mRS ≤2 vs mRS ≥3), successful revascularization, symptomatic intracranial hemorrhage (ICH), and mortality.108 patients met the inclusion criteria, including 79 octogenarians (73%) and 29 nonagenarians (27%). Nonagenarians were more likely to be female (86% vs 58%; p<0.01); there were no other differences between groups in terms of demographics, medical comorbidities, or treatment characteristics. Successful revascularization (TICI 2b-3) was achieved in 79% in both cohorts. Median mRS at 90 days was 5 in octogenarians and 6 in nonagenarians (p=0.09). Functional independence (mRS ≤2) at 90 days was achieved in 12.5% and 19.7% of nonagenarians and octogenarians, respectively (p=0.54). Symptomatic ICH occurred in 21.4% and 6.4% (p=0.03), and 90-day mortality rate was 63% and 40.9% (p=0.07) in nonagenarians and octogenarians, respectively.Nonagenarians may be at higher risk of symptomatic ICH than octogenarians, despite similar stroke- and treatment-related factors. While there was a trend towards higher mortality and worse functional outcomes in nonagenarians, the difference was not statistically significant in this relatively small retrospective study.

    View details for DOI 10.1136/neurintsurg-2019-015147

    View details for PubMedID 31350369

  • Contralateral Hemispheric Cerebral Blood Flow Measured With Arterial Spin Labeling Can Predict Outcome in Acute Stroke. Stroke Thamm, T. n., Guo, J. n., Rosenberg, J. n., Liang, T. n., Marks, M. P., Christensen, S. n., Do, H. M., Kemp, S. M., Adair, E. n., Eyngorn, I. n., Mlynash, M. n., Jovin, T. G., Keogh, B. P., Chen, H. J., Lansberg, M. G., Albers, G. W., Zaharchuk, G. n. 2019: STROKEAHA119026499


    Background and Purpose- Imaging is frequently used to select acute stroke patients for intra-arterial therapy. Quantitative cerebral blood flow can be measured noninvasively with arterial spin labeling magnetic resonance imaging. Cerebral blood flow levels in the contralateral (unaffected) hemisphere may affect capacity for collateral flow and patient outcome. The goal of this study was to determine whether higher contralateral cerebral blood flow (cCBF) in acute stroke identifies patients with better 90-day functional outcome. Methods- Patients were part of the prospective, multicenter iCAS study (Imaging Collaterals in Acute Stroke) between 2013 and 2017. Consecutive patients were enrolled after being diagnosed with anterior circulation acute ischemic stroke. Inclusion criteria were ischemic anterior circulation stroke, baseline National Institutes of Health Stroke Scale score ≥1, prestroke modified Rankin Scale score ≤2, onset-to-imaging time <24 hours, with imaging including diffusion-weighted imaging and arterial spin labeling. Patients were dichotomized into high and low cCBF groups based on median cCBF. Outcomes were assessed by day-1 and day-5 National Institutes of Health Stroke Scale; and day-30 and day-90 modified Rankin Scale. Multivariable logistic regression was used to test whether cCBF predicted good neurological outcome (modified Rankin Scale score, 0-2) at 90 days. Results- Seventy-seven patients (41 women) met the inclusion criteria with median (interquartile range) age of 66 (55-76) yrs, onset-to-imaging time of 4.8 (3.6-7.7) hours, and baseline National Institutes of Health Stroke Scale score of 13 (9-20). Median cCBF was 38.9 (31.2-44.5) mL per 100 g/min. Higher cCBF predicted good outcome at day 90 (odds ratio, 4.6 [95% CI, 1.4-14.7]; P=0.01), after controlling for baseline National Institutes of Health Stroke Scale, diffusion-weighted imaging lesion volume, and intra-arterial therapy. Conclusions- Higher quantitative cCBF at baseline is a significant predictor of good neurological outcome at day 90. cCBF levels may inform decisions regarding stroke triage, treatment of acute stroke, and general outcome prognosis. Clinical Trial Registration- URL: Unique identifier: NCT02225730.

    View details for DOI 10.1161/STROKEAHA.119.026499

    View details for PubMedID 31619150

  • Can diffusion- and perfusion-weighted imaging alone accurately triage anterior circulation acute ischemic stroke patients to endovascular therapy? JOURNAL OF NEUROINTERVENTIONAL SURGERY Wolman, D. N., Iv, M., Wintermark, M., Zaharchuk, G., Marks, M. P., Do, H. M., Dodd, R. L., Albers, G. W., Lansberg, M. G., Heit, J. J. 2018; 10 (12): 1132-+
  • Management of Complex Arteriovenous Malformations Using a Novel Combination Therapeutic Algorithm. JAMA dermatology Chelliah, M. P., Do, H. M., Zinn, Z., Patel, V., Jeng, M., Khosla, R. K., Truong, M., Marqueling, A., Teng, J. M. 2018; 154 (11): 1316–19


    Importance: Current therapeutic options for patients with extracranial head and neck arteriovenous malformations are limited. Surgical intervention, such as sclerotherapy or resection, often result in rapid recurrence and progression of disease.Objective: To assess the efficacy and tolerability of sirolimus as an adjuvant therapy for endovascular embolization in the management of complicated extracranial head and neck arteriovenous malformations.Design, Setting, and Participants: This case series examined 6 patients with extracranial head and neck arteriovenous malformations treated from January 1, 2013, to December 31, 2017, at a multidisciplinary vascular anomalies clinic within Stanford Hospital and Clinics.Intervention: Initiation of sirolimus at least 1 month prior to endovascular embolization, targeting a trough level of 10 to 15 ng/mL throughout the course of the endovascular embolization series and continued for at least 1 month after the series.Main Outcomes and Measures: Clinical manifestations; disease progression and overall response to treatment were assessed via clinical evaluation and radiographic imaging.Results: All 6 patients (4 male and 2 female patients; mean age, 24.5 years [range, 9-44 years]) responded favorably to the combination of sirolimus therapy followed by endovascular embolization, and 4 patients exhibited a near-complete response. The median duration of follow-up was 19 months (range, 6-40 months). One patient discontinued sirolimus soon after embolization and experienced regrowth of the arteriovenous malformation after 1 year. Sirolimus was resumed, which has stabilized his disease for more than 2 years. Mild adverse effects were noted in 4 patients. The combination therapy was well tolerated in all patients. One patient developed skin ulceration after embolization and required surgical debridement. Another patient developed pulmonary microthrombi after embolization with cyanoacrylate glue that resolved with a brief course of anti-inflammatory therapy.Conclusions and Relevance: Although further prospective trials are needed, this report suggests the benefit of a mammalian target of rapamycin inhibitor as an adjuvant therapy for surgical embolization of complex, extracranial head and neck arteriovenous malformations. The optimal dosing and therapeutic duration of sirolimus treatment before and after embolization remain to be determined.

    View details for PubMedID 30326494

  • Early Cerebral Vein After Endovascular Ischemic Stroke Treatment Predicts Symptomatic Reperfusion Hemorrhage STROKE Cartmell, S. D., Ball, R. L., Kaimal, R., Telischak, N. A., Marks, M. P., Do, H. M., Dodd, R. L., Albers, G. W., Lansberg, M. G., Heit, J. J. 2018; 49 (7): 1741–46
  • Spontaneous regression of an idiopathic arteriovenous fistula of the right vertebral artery NEURORADIOLOGY Choudhri, O., Dobre, M. C., Feroze, A., Sharma, N., Do, H. M. 2018; 60 (2): 221–23


    A previously healthy 53-year-old male presented with a 2-month history of pulsatile tinnitus, worsening headaches, and neck pain. Given the clinical symptoms, a workup was initiated to assess for a vascular etiology such as a dural arteriovenous fistula.

    View details for PubMedID 29260274

  • Wingspan stent delivery catheter fracture and the TRAP technique for endovascular salvage. Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences Jagani, M. n., Do, H. M., Heit, J. J. 2018; 24 (1): 106–10


    Background Intracranial atherosclerotic disease may result in ischemic infarction and has a high rate of recurrent ischemic strokes despite medical therapy. Patients who fail medical therapy may undergo endovascular treatment with cerebral artery angioplasty and possible Wingspan stent placement. We present a unique case of Wingspan delivery microcatheter fracture that resulted in a retained foreign body and an endovascular salvage maneuver. Case description An elderly patient presented with an acute ischemic stroke due to a severe stenosis in the proximal left middle cerebral artery (MCA). The patient failed non-invasive medical treatment and underwent endovascular treatment with angioplasty and Wingspan stent placement. Following Wingspan stent deployment, the stent delivery catheter fractured, and the retained catheter fragment resulted in MCA occlusion. The foreign body was retrieved by balloon catheter inflation within an intermediate catheter adjacent to the proximal end of the fractured catheter and removal of the entire construct (TRAP technique). Conclusions Wingspan delivery microcatheter fracture is a rare event. The TRAP technique may be used for successful retrieval of a retained foreign body.

    View details for PubMedID 29125024

  • Reduced Intravoxel Incoherent Motion Microvascular Perfusion Predicts Delayed Cerebral Ischemia and Vasospasm After Aneurysm Rupture. Stroke Heit, J. J., Wintermark, M. n., Martin, B. W., Zhu, G. n., Marks, M. P., Zaharchuk, G. n., Dodd, R. L., Do, H. M., Steinberg, G. K., Lansberg, M. G., Albers, G. W., Federau, C. n. 2018


    Proximal artery vasospasm and delayed cerebral ischemia (DCI) after cerebral aneurysm rupture result in reduced cerebral perfusion and microperfusion and significant morbidity and mortality. Intravoxel incoherent motion (IVIM) magnetic resonance imaging extracts microvascular perfusion information from a multi-b value diffusion-weighted sequence. We determined whether decreased IVIM perfusion may identify patients with proximal artery vasospasm and DCI.We performed a pilot retrospective cohort study of patients with ruptured cerebral aneurysms. Consecutive patients who underwent a brain magnetic resonance imaging with IVIM after ruptured aneurysm treatment were included. Patient demographic, treatment, imaging, and outcome data were determined by electronic medical record review. Primary outcome was DCI development with proximal artery vasospasm that required endovascular treatment. Secondary outcomes included mortality and clinical outcomes at 6 months.Sixteen patients (11 females, 69%;P=0.9) were included. There were no differences in age, neurological status, or comorbidities between patients who subsequently underwent endovascular treatment of DCI (10 patients; DCI+ group) and those who did not (6 patients; DCI- group). Compared with DCI- patients, DCI+ patients had decreased IVIM perfusion fractionf(0.09±0.03 versus 0.13±0.01;P=0.03), reduced diffusion coefficientD(0.82±0.05 versus 0.92±0.07×10-3mm2/s;P=0.003), and reduced blood flow-related parameterfD* (1.18±0.40 versus 1.83±0.40×10-3mm2/s;P=0.009). IVIM pseudodiffusion coefficientD* did not differ between DCI- (0.011±0.002) and DCI+ (0.013±0.005 mm2/s;P=0.4) patients. No differences in mortality or clinical outcome were identified.Decreased IVIM perfusion fractionfand blood flow-related parameterfD* correlate with DCI and proximal artery vasospasm development after cerebral aneurysm rupture.

    View details for DOI 10.1161/STROKEAHA.117.020395

    View details for PubMedID 29439196

  • Sofia intermediate catheter and the SNAKE technique: safety and efficacy of the Sofia catheter without guidewire or microcatheter construct. Journal of neurointerventional surgery Heit, J. J., Wong, J. H., Mofaff, A. M., Telischak, N. A., Dodd, R. L., Marks, M. P., Do, H. M. 2018; 10 (4): 401–6


    Neurointerventional surgeries (NIS) benefit from supportive endovascular constructs. Sofia is a soft-tipped, flexible, braided single lumen intermediate catheter designed for NIS. Sofia advancement from the cervical to the intracranial circulation without a luminal guidewire or microcatheter construct has not been described.To evaluate the efficacy and safety of the new Sofia Non-wire Advancement techniKE (SNAKE) for advancement of the Sofia into the cerebral circulation.Consecutive patients who underwent NIS using Sofia were identified. Patient information, SNAKE use, and patient outcome were determined from electronic medical records. Sofia advancement to the cavernous internal carotid artery or the V2/V3 segment junction of the vertebral artery was the primary outcome measure. Secondary outcomes included arterial vasospasm and arterial dissection.263 Patients (181 females, 69%) who underwent a total of 305 NIS using Sofia were identified. SNAKE (SNAKE+) was used in 187 procedures (61%). Two hundred and ninety-three procedures (96%) were technically successful, which included 184 SNAKE+ NIS and 109 SNAKE- NIS. Primary outcome was achieved in all SNAKE+ procedures, but not in five SNAKE- procedures (2%). No arterial dissections were identified among 305 interventions. In the intracranial circulation, a single SNAKE+ patient (0.5%) had non-flow limiting arterial vasospasm involving the petrous internal carotid. Three SNAKE+ patients (1.6%) and one SNAKE- patient (0.8%) demonstrated external carotid artery branch artery vasospasm during dural arteriovenous fistula or facial arteriovenous malformation treatment.SNAKE is a safe and effective technique for Sofia advancement. Sofia is a highly effective and safe intermediate catheter for a variety of NIS.

    View details for PubMedID 28768818

  • Fluoroscopic C-Arm and CT-Guided Selective Radiofrequency Ablation for Trigeminal and Glossopharyngeal Facial Pain Syndromes. Pain medicine (Malden, Mass.) Telischak, N. A., Heit, J. J., Campos, L. W., Choudhri, O. A., Do, H. M., Qian, X. 2017


     Percutaneous radiofrequency ablation (RFA) of the gasserian ganglion through the foramen ovale and the glossopharyngeal nerve at the jugular foramen is a classical approach to treating trigeminal neuralgia (TN) and glossopharyngeal neuralgia (GPN), respectively. However, it can be technically challenging with serious complications. We have thus developed a novel technique utilizing C-arm and computerized tomography (CT) guidance to block TN and GPN. Our goals were to describe a three-dimensional image-based technique to improve patient comfort and to decrease procedural time associated with needle guidance.Consecutive procedures were reviewed. Academic hospital.Three patients with classical TN and GPN and 15 patients with atypical facial pain (AFP) were treated. Numeric rating scale (NRS) scores for pain at pretreatment and at one, three, and 12 months post-treatment were recorded. The primary clinical outcome (50% or more reduction in NRS) and secondary adverse clinical outcome (hematoma, facial numbness, etc.) were monitored. We had a 100% technical success with respect to appropriate needle positioning. All three classical TN/GPN patients had both immediate and sustained pain relief. Complications were minimal. The 15 AFP patients, however, showed more variable results, with only five (33%) having sustained pain relief, while in the other 10 (67%) patients, we observed suboptimal response. We present a novel method and single-center experience with C-arm and CT-guided RFA of facial pain. Quick and accurate needle placement will help future advancements in the RFA algorithm so that more durable and consistent effects can be attained, reducing uncertainty with respect to needle placement as a confounder. The RFA procedure in our study had a satisfying effect for classical TN/GPN patients but was less successful for AFP patients, though it did mirror the results from previous studies.This study is limited by its small sample size and nonrandomized design.

    View details for DOI 10.1093/pm/pnx088

    View details for PubMedID 28472393

  • Embolization Followed by Radiosurgery for the Treatment of Brain Arteriovenous Malformations (AVMs) WORLD NEUROSURGERY Marks, M. P., Marcellus, M. L., Santarelli, J., Dodd, R. L., Do, H. M., Chang, S. D., Adler, J. R., Mlynash, M., Steinberg, G. K. 2017; 99: 471-476


    Embolization has been proposed to reduce the size of the arteriovenous malformation (AVM) nidus in advance of radiosurgical treatment. Embolization followed by radiosurgery for brain AVMs, however, is controversial.We assessed the impact of embolization on nidal size before radiosurgical treatment and evaluated cure rates and complications by using embolization followed by radiosurgery.A retrospective review of our institutional AVM database identified 91 patients treated from 1995 to 2009 with embolization followed by radiosurgery. Pre- and postembolization AVM volumes were measured with angiography, and the modified radiation-based AVM scores (RBAS) also were calculated pre- and postembolization. RBAS determined from pre-embolization volumes were correlated with postradiosurgical obliteration.Median AVM volume declined from 18.8 mL (interquartile range, 10.2-32.2 mL) to 9.9 mL (3.1-19.2 mL) after embolization, P < 0.00003. Median RBAS scores decreased from 2.6 mL (1.8-3.9 mL) to 1.8 mL (1.0-2.8 mL), P < 0.00003. Two of 91 (2.2%) had new fixed deficits after embolization; however, no patient had new disabling deficits (modified Rankin Scale score >2). A total of 71 of 91 (79%) have had >3 years' follow-up, and 40 (56%) had complete obliteration, with 38 (53%) having excellent outcomes (complete obliteration without neurologic decline). Excellent outcome was seen in 90% of patients with modified RBAS score <1, 66% of patients with score 1-1.5, 50% patients with score 1.5-2, and 43% of patients with score >2.These data suggest that embolization of brain AVMs can safely and effectively reduce the treatment volume before radiosurgery. Combined therapy with embolization and radiosurgery does not appear to adversely affect rates of excellent outcome.

    View details for DOI 10.1016/j.wneu.2016.12.059

    View details for Web of Science ID 000397190100066

  • Asystole During Onyx Embolization of a Pediatric Arteriovenous Malformation: A Severe Case of the Trigeminocardiac Reflex. World neurosurgery Khatibi, K., Choudhri, O., Connolly, I. D., McTaggart, R. A., Do, H. M. 2017; 98: 884 e1-884 e5


    Trigeminal-cardiac reflex (TCR) from the stimulation of sensory branches of trigeminal nerve can lead to hemodynamic instability. This phenomenon has been described during ophthalmologic, craniofacial, and skull base surgeries. TCR has been reported rarely with endovascular onyx embolization of dural arteriovenous fistulas.We report a case of TCR during endovascular Onyx embolization of an arteriovenous malformation (AVM). A 16-year-old boy presented with a large cerebellar AVM with arterial feeders from the external carotid artery and posterior cerebral artery branches. The middle meningeal artery was catheterized, through which dimethyl sulfoxide was injected, followed by Onyx, into the nidus and the feeders. Near the completion of embolization, patient became bradycardic and proceeded to asystole; he was resuscitated with chest compression, atropine, and vasopressors. We used PubMed to identify the reported cases of Onyx and other endovascular embolizations complicated by hemodynamic instability. We found 16 cases of endovascular onyx embolization complicated by clinically significant hemodynamic changes in the treatment of dural arteriovenous fistula, cavernous carotid fistula, and juvenile nasopharygeal angiofibroma but not with AVMs. In these cases, arterial supply to the nidus involved the sensory receptive field of trigeminal nerve. Hemodynamic changes have been reported during the injection of dimethyl sulfoxide before the introduction of Onyx, as well as Onyx injection and cast formation.TCR can lead to significant hemodynamic changes during endovascular Onyx embolization of vascular malformations (both pial AVM and dural arteriovenous fistulas) involving receptive field of trigeminal nerve. Therefore, the anesthesiologist should be made aware of treatment approach before intervention and appropriate precautions taken.

    View details for DOI 10.1016/j.wneu.2016.07.025

    View details for PubMedID 27436213

  • Complications Following Transradial Cerebral Angiography : An Ultrasound Follow-Up Study. Journal of Korean Neurosurgical Society Yoon, W. n., Kwon, W. K., Choudhri, O. n., Ahn, J. n., Huh, H. n., Ji, C. n., Do, H. M., Mantha, A. n., Jeun, S. S. 2017


    The feasibility and usefulness of transradial catheterization for coronary and neuro-intervention are well known. However, the anatomical change in the catheterized radial artery (RA) is not well understood. Herein, we present the results of ultrasonographic observation of the RA after routine transradial cerebral angiography (TRCA).Patients who underwent routine TRCA with pre- and post-procedure Doppler ultrasonography (DUS) of the catheterized RA were enrolled. We then recorded and retrospectively reviewed the diameter and any complicated features of the RA observed on DUS, and the factors associated with the diameter and complications were analyzed.A total of 223 TRCAs across 181 patients were enrolled in the current study. The mean RA diameter was 2.48 mm and was positively correlated with male gender (p<0.001) and hypertension (p<0.002). The median change in diameter after TRCA was less than 0.1 mm (range, -1.3 to 1.2 mm) and 90% of changes were between -0.8 and +0.7 mm. Across 228 procedures, there were 12 cases (5.3%) of intimal hyperplasia and 22 cases (9.6%) of asymptomatic local vascular complications found on DUS. Patients with abnormal findings on the first procedure had a smaller pre-procedural RA diameter than that of patients without findings (2.26 vs. 2.53 mm, p=0.0028). There was no significant difference in the incidence of abnormal findings for the first versus subsequent procedures (p=0.68).DUS identified the pre- and post-procedural diameter and local complications of RA. Routine TRCA seems to be acceptable with regard to identifying local complications and changes in RA diameter.

    View details for PubMedID 29207853

    View details for PubMedCentralID PMC5769853

  • Pipeline embolization device retraction and foreshortening after internal carotid artery blister aneurysm treatment. Interventional neuroradiology : journal of peritherapeutic neuroradiology, surgical procedures and related neurosciences Heit, J. J., Telischak, N. A., Do, H. M., Dodd, R. L., Steinberg, G. K., Marks, M. P. 2017; 23 (6): 614–19


    Background Subarachnoid hemorrhage (SAH) secondary to rupture of a blister aneurysm (BA) results in high morbidity and mortality. Endovascular treatment with the pipeline embolization device (PED) has been described as a new treatment strategy for these lesions. We present the first reported case of PED retraction and foreshortening after treatment of a ruptured internal carotid artery (ICA) BA. Case description A middle-aged patient presented with SAH secondary to ICA BA rupture. The patient was treated with telescoping PED placement across the BA. After 5 days from treatment, the patient developed a new SAH due to re-rupture of the BA. Digital subtraction angiography revealed an increase in caliber of the supraclinoid ICA with associated retraction and foreshortening of the PED that resulted in aneurysm uncovering and growth. Conclusions PED should be oversized during ruptured BA treatment to prevent device retraction and aneurysm regrowth. Frequent imaging follow up after BA treatment with PED is warranted to ensure aneurysm occlusion.

    View details for PubMedID 28758549

  • Patient Outcomes and Cerebral Infarction after Ruptured Anterior Communicating Artery Aneurysm Treatment. AJNR. American journal of neuroradiology Heit, J. J., Ball, R. L., Telischak, N. A., Do, H. M., Dodd, R. L., Steinberg, G. K., Chang, S. D., Wintermark, M. n., Marks, M. P. 2017; 38 (11): 2119–25


    Anterior communicating artery aneurysm rupture and treatment is associated with high rates of dependency, which are more severe after clipping compared with coiling. To determine whether ischemic injury might account for these differences, we characterized cerebral infarction burden, infarction patterns, and patient outcomes after surgical or endovascular treatment of ruptured anterior communicating artery aneurysms.We performed a retrospective cohort study of consecutive patients with ruptured anterior communicating artery aneurysms. Patient data and neuroimaging studies were reviewed. A propensity score for outcome measures was calculated to account for the nonrandom assignment to treatment. Primary outcome was the frequency of frontal lobe and striatum ischemic injury. Secondary outcomes were patient mortality and clinical outcome at discharge and at 3 months.Coiled patients were older (median, 55 versus 50 years;P= .03), presented with a worse clinical status (60% with Hunt and Hess Score >2 versus 34% in clipped patients;P= .02), had a higher modified Fisher grade (P= .01), and were more likely to present with intraventricular hemorrhage (78% versus 56%;P= .03). Ischemic frontal lobe infarction (OR, 2.9; 95% CI, 1.1-8.4;P= .03) and recurrent artery of Heubner infarction (OR, 20.9; 95% CI, 3.5-403.7;P< .001) were more common in clipped patients. Clipped patients were more likely to be functionally dependent at discharge (OR, 3.2;P= .05) compared with coiled patients. Mortality and clinical outcome at 3 months were similar between coiled and clipped patients.Frontal lobe and recurrent artery of Heubner infarctions are more common after surgical clipping of ruptured anterior communicating artery aneurysms, and are associated with poorer clinical outcomes at discharge.

    View details for PubMedID 28882863

  • Surgical outcomes of Majewski osteodysplastic primordial dwarfism Type II with intracranial vascular anomalies. Journal of neurosurgery. Pediatrics Teo, M., Johnson, J. N., Bell-Stephens, T. E., Marks, M. P., Do, H. M., Dodd, R. L., Bober, M. B., Steinberg, G. K. 2016; 25 (6): 717-723


    OBJECTIVE Majewski osteodysplastic primordial dwarfism Type II (MOPD II) is a rare genetic disorder. Features of it include extremely small stature, severe microcephaly, and normal or near-normal intelligence. Previous studies have found that more than 50% of patients with MOPD II have intracranial vascular anomalies, but few successful surgical revascularization or aneurysm-clipping cases have been reported because of the diminutive arteries and narrow surgical corridors in these patients. Here, the authors report on a large series of patients with MOPD II who underwent surgery for an intracranial vascular anomaly. METHODS In conjunction with an approved prospective registry of patients with MOPD II, a prospectively collected institutional surgical database of children with MOPD II and intracranial vascular anomalies who underwent surgery was analyzed retrospectively to establish long-term outcomes. RESULTS Ten patients with MOPD II underwent surgery between 2005 and 2012; 5 patients had moyamoya disease (MMD), 2 had intracranial aneurysms, and 3 had both MMD and aneurysms. Patients presented with transient ischemic attack (TIA) (n = 2), ischemic stroke (n = 2), intraparenchymal hemorrhage from MMD (n = 1), and aneurysmal subarachnoid hemorrhage (n = 1), and 4 were diagnosed on screening. The mean age of the 8 patients with MMD, all of whom underwent extracranial-intracranial revascularization (14 indirect, 1 direct) was 9 years (range 1-17 years). The mean age of the 5 patients with aneurysms was 15.5 years (range 9-18 years). Two patients experienced postoperative complications (1 transient weakness after clipping, 1 femoral thrombosis that required surgical repair). During a mean follow-up of 5.9 years (range 3-10 years), 3 patients died (1 of subarachnoid hemorrhage, 1 of myocardial infarct, and 1 of respiratory failure), and 1 patient had continued TIAs. All of the surviving patients recovered to their neurological baseline. CONCLUSIONS Patients with MMD presented at a younger age than those in whom aneurysms were more prevalent. Microneurosurgery with either intracranial bypass or aneurysm clipping is extremely challenging but feasible at expert centers in patients with MOPD II, and good long-term outcomes are possible.

    View details for PubMedID 27611897

  • Headway Duo microcatheter for cerebral arteriovenous malformation embolization with n-BCA. Journal of neurointerventional surgery Heit, J. J., Faisal, A. G., Telischak, N. A., Choudhri, O., Do, H. M. 2016; 8 (11): 1181-1185


    Cerebral arteriovenous malformations (AVMs) are uncommon vascular lesions, and hemorrhage secondary to AVM rupture results in significant morbidity and mortality. AVMs may be treated by endovascular embolization, and technical advances in microcatheter design are likely to improve the success and safety of endovascular embolization of cerebral AVMs.To describe our early experience with the Headway Duo microcatheter for embolization of cerebral AVMs with n-butyl-cyanoacrylate (n-BCA).Consecutive patients treated by endovascular embolization of a cerebral AVM with n-BCA delivered intra-arterially through the Headway Duo microcatheter (167 cm length) were identified. Patient demographic information, procedural details, and patient outcome were determined from electronic medical records.Ten consecutive patients undergoing cerebral AVM embolization using n-BCA injected through the Headway Duo microcatheter were identified. Presenting symptoms included headache, hemorrhage, seizures, and weakness. Spetzler Martin grades ranged from 1 to 5, and AVMs were located in the basal ganglia (2 patients), parietal lobe (4 patients), frontal lobe (1 patient), temporal lobe (1 patient), an entire hemisphere (1 patient), and posterior fossa (1 patient). 50 arterial pedicles were embolized, and all procedures were technically successful. There was one post-procedural hemorrhage that was well tolerated by the patient, and no other complications occurred. Additional AVM treatment was performed by surgery and radiation therapy.The Headway Duo microcatheter is safe and effective for embolization of cerebral AVMs using n-BCA. The trackability and high burst pressure of the Headway Duo make it an important and useful tool for the neurointerventionalist during cerebral AVM embolization.

    View details for DOI 10.1136/neurintsurg-2015-012094

    View details for PubMedID 26603031

  • Operative volume and outcomes of cerebrovascular neurosurgery in children. Journal of neurosurgery. Pediatrics Bekelis, K., Connolly, I. D., Do, H. M., Choudhri, O. 2016; 18 (5): 623-628


    OBJECTIVE The impact of procedural volume on the outcomes of cerebrovascular surgery in children has not been determined. In this study, the authors investigated the association of operative volume on the outcomes of cerebrovascular neurosurgery in pediatric patients. METHODS The authors performed a cohort study of all pediatric patients who underwent a cerebrovascular procedure between 2003 and 2012 and were registered in the Kids' Inpatient Database (KID). To control for confounding, the authors used multivariable regression models, propensity-score conditioning, and mixed-effects analysis to account for clustering at the hospital level. RESULTS During the study period, 1875 pediatric patients in the KID underwent cerebrovascular neurosurgery and met the inclusion criteria for the study; 204 patients (10.9%) underwent aneurysm clipping, 446 (23.8%) underwent coil insertion for an aneurysm, 827 (44.1%) underwent craniotomy for arteriovenous malformation resection, and 398 (21.2%) underwent bypass surgery for moyamoya disease. Mixed-effects multivariable regression analysis revealed that higher procedural volume was associated with fewer inpatient deaths (OR 0.58; 95% CI 0.40-0.85), a lower rate of discharges to a facility (OR 0.87; 95% CI 0.82-0.92), and shorter length of stay (adjusted difference -0.22; 95% CI -0.32 to -0.12). The results in propensity-adjusted multivariable models were robust. CONCLUSIONS In a national all-payer cohort of pediatric patients who underwent a cerebrovascular procedure, the authors found that higher procedural volume was associated with fewer deaths, a lower rate of discharges to a facility, and decreased lengths of stay. Regionalization initiatives should include directing children with such rare pathologies to a center of excellence.

    View details for PubMedID 27494548

  • Initial experience with SOFIA as an intermediate catheter in mechanical thrombectomy for acute ischemic stroke. Journal of neurointerventional surgery Wong, J. H., Do, H. M., Telischak, N. A., Moraff, A. M., Dodd, R. L., Marks, M. P., Ingle, S. M., Heit, J. J. 2016


    The benefits of mechanical thrombectomy for emergent large vessel occlusion (ELVO) have been established. Combined mechanical/aspiration (Solumbra) and a direct aspiration as a first pass technique (ADAPT) are valid procedures requiring an intermediate catheter for clot suction. Recently, SOFIA (Soft torqueable catheter Optimized For Intracranial Access) was developed as a single lumen flexible catheter with coil and braid reinforcement, but its suitability for mechanical thrombectomy had not been evaluated.To describe our initial experience with SOFIA in acute stroke intervention and evaluate its efficacy and safety.All patients with ELVO undergoing endovascular stroke intervention with SOFIA were identified. Demographic, presentation, treatment, and complication data were recorded. Primary outcome was Thrombolysis in Cerebral Infarction (TICI) 2b/3 revascularization rate and the number of passes required. Secondary outcomes included complication rates and discharge National Institute of Health Stroke Scale (NIHSS) score.33 patients with a mean age of 72 years were treated for ELVO with SOFIA and IV tissue plasminogen activator was administered in 67%. Vessel occlusion involved the internal carotid artery (15.2%), M1 (48.5%), and M2 (24.2%) segments, and posterior circulation (12.1%). Median presentation NIHSS score was 14 (IQR 11-19) and discharge NIHSS 4 (IQR 2-14). The Solumbra technique represented 94% of treatments and ADAPT 3%. The TICI 2b/3 revascularization rate was 94%, including 48.5% TICI 3 with an average of 1.6 passes. The symptomatic reperfusion hemorrhage rate was 6%. Procedural complications occurred in four patients, but were unrelated to SOFIA. Mortality was 21%, secondary to failed revascularization, hemorrhagic transformation, and baseline medical condition.Mechanical and aspiration thrombectomy with SOFIA is safe and effective with high revascularization rates. Its trackability, stability, and luminal size make SOFIA suitable for stroke intervention.

    View details for DOI 10.1136/neurintsurg-2016-012750

    View details for PubMedID 27789787

  • Sclerotherapy for lymphatic malformations of the head and neck in the pediatric population. Journal of neurointerventional surgery Tu, J. H., Do, H. M., Patel, V., Yeom, K. W., Teng, J. M. 2016


    Sclerotherapy is one of the most commonly used minimally invasive interventions in the treatment of macrocystic lymphatic malformations (LMs). Several different sclerosing agents and injection protocols have been reported in the literature, each with varying degrees of success. The safety and efficacy of the treatments have not been evaluated comparatively in the pediatric population.Chart review of pediatric patients with macrocystic/mixed head and neck LMs who underwent sclerotherapy using OK-432, doxycycline, or ethanolamine oleate at Lucile Packard Children's Hospital at Stanford during 2000-2014. Clinical evaluation and radiographic imaging were reviewed to assess lesion characteristics and response to sclerotherapy following each treatment session. The post-intervention clinical response was categorized as excellent, good, fair, or poor.Among the 41 pediatric cases reviewed, 10 patients were treated with OK-432, 19 patients received doxycycline, and 12 patients received ethanolamine. In univariate analysis, different sclerosants had similar effectiveness after the first injection and final clinical outcome (p=0.5317). In multivariate analysis controlling for disease severity stage as well as disease characteristics (macrocystic vs mixed subtypes), different sclerosants also had similar effectiveness after the first injection (p=0.1192). Radiologic analysis indicated an 84.5% average volume reduction, with similar effectiveness between the different sclerosants (p=0.9910).In this series of LM cases treated at Stanford, we found that doxycycline, OK-432, and ethanolamine oleate sclerotherapy appear to have a similar safety and efficacy profile in the treatment of macrocystic and mixed LMs of the head and neck in the pediatric population.

    View details for DOI 10.1136/neurintsurg-2016-012660

    View details for PubMedID 27707871

  • Increased risk for complications following diagnostic cerebral angiography in older patients: Trends from the Nationwide Inpatient Sample (1999-2009). Journal of clinical neuroscience Choudhri, O., Schoen, M., Mantha, A., Feroze, A., Ali, R., Lawton, M. T., Do, H. M. 2016; 32: 109-114


    The full utility of diagnostic cerebral angiography, an invasive cerebrovascular imaging technique, is currently debated. Our goal was to determine trends in diagnostic cerebral angiography utilization and associated complications from 1999 through 2009. The National Inpatient Sample (NIS) was used to identify patients who received primary cerebral angiography from 1999-2009 in the United States. We observed trends in discharge volume, total mean charge, and post-procedural complications for this population. Data was based on sample projections and analyzed using univariate and multivariate regression. There were a total of 424,105 discharges indicating primary cerebral angiography nationwide from 1999-2009. The majority of these cases (65%) were in patients older than 55years. Embolic stroke was the most frequent complication, particularly in the oldest age bracket, occurring in 16,304 patients. The risk for complications increased with age (p<0.0001) and with other underlying health conditions. Pulmonary, deep vein thrombosis, and renal associated comorbidities resulted in the greatest risk for developing post-procedural complications. Throughout the study period case volume for cerebral angiography remained constant while total charge per patient increased from $17,365 in 1999 to $45,339 in 2009 (p<0.001). While the overall complication rate for this invasive procedure is relatively low, the potential risk for embolic stroke in older patients is significant. It is worth considering less invasive diagnostic techniques for an older and at risk patient population.

    View details for DOI 10.1016/j.jocn.2016.04.007

    View details for PubMedID 27430411

  • Cerebral vascular findings in PAPA syndrome: cerebral arterial vasculopathy or vasculitis and a posterior cerebral artery dissecting aneurysm. Journal of neurointerventional surgery Khatibi, K., Heit, J. J., Telischak, N. A., Elbers, J. M., Do, H. M. 2016; 8 (8)


    A young patient with PAPA (pyogenic arthritis, pyoderma gangrenosum, and acne) syndrome developed an unusual cerebral arterial vasculopathy/vasculitis (CAV) that resulted in subarachnoid hemorrhage from a ruptured dissecting posterior cerebral artery (PCA) aneurysm. This aneurysm was successfully treated by endovascular coil sacrifice of the affected segment of the PCA. The patient made an excellent recovery with no significant residual neurologic deficit.

    View details for DOI 10.1136/neurintsurg-2015-011753.rep

    View details for PubMedID 26122324

  • Management of moyamoya syndrome in patients with Noonan syndrome JOURNAL OF CLINICAL NEUROSCIENCE Gupta, M., Choudhri, O. A., Feroze, A. H., Do, H. M., Grant, G. A., Steinberg, G. K. 2016; 28: 107-111


    A few isolated reports have described an association between Noonan syndrome and cerebrovascular abnormalities, including moyamoya syndrome. These reports have been limited to pediatric patients presenting with recurrent transient ischemic attacks (TIA) or headaches. Management has primarily been pharmacologic, with only one prior report of surgical revascularization to our knowledge. We report four cases of Noonan syndrome patients presenting with headaches and/or sensorimotor strokes in childhood that caused unilateral sensorimotor impairment. Cerebral angiography and MRI revealed bilateral moyamoya syndrome. All patients underwent successful bilateral extracranial-to-intracranial revascularization. The first patient was a 10-year-old girl who presented following a hemorrhagic stroke and recovered well after indirect bypass. The second patient was an adult with a history of childhood stroke whose symptoms progressed in adulthood. She underwent a direct bypass and improved, but continued to experience TIA at her 4 year follow-up. The third patient was a 7-year-old girl with headaches and a new onset TIA who failed pharmacological therapy and subsequently underwent bilateral indirect bypass. The fourth patient was a 24-year-old woman with worsening headaches and an occluded left middle cerebral artery from unilateral moyamoya syndrome. A left sided direct bypass was completed given delayed MRI perfusion with poor augmentation. To our knowledge these are the first reported surgical cases of combined Noonan and moyamoya syndrome. These cases highlight the need to recognize moyamoya syndrome in patients with Noonan syndrome. Early surgical revascularization should be pursued in order to prevent symptom progression.

    View details for DOI 10.1016/j.jocn.2015.11.017

    View details for Web of Science ID 000376714500021

    View details for PubMedID 26778511

  • Quantitative volumetric analysis of head and neck venous and lymphatic malformations to assess response to percutaneous sclerotherapy. Acta radiologica Alexander, M. D., McTaggart, R. A., Choudhri, O. A., Pandit, R. P., Wu, A., Ross, M., Do, H. M. 2016; 57 (2): 205-209


    Venous and lymphatic malformations of the head and neck can be successfully treated with percutaneous sclerotherapy.To examine the utility of three-dimensional volumetric analysis to assess these lesions and their response to therapy.Prospectively maintained procedure records were retrospectively reviewed to identify all patients with vascular malformations who underwent percutaneous sclerotherapy. Clinical data were used to classify lesions by apparent size and degree of visible physical asymmetry due to the lesions. Lesion volume was calculated using magnetic resonance images. Cohen's weighted kappa coefficients were calculated to assess both intra- and inter-rater agreement. Pearson coefficients were calculated to identify correlation between clinical and volumetric measures, both at initial diagnosis and following treatment.Thirty-seven patients with head and neck venous or lymphatic malformations underwent 55 treatment sessions. Cohen's weighted kappa coefficients were 0.84 and 0.77 for intra- and inter-rater agreement, respectively. Clinical size did not significantly correlate with measured volume at diagnosis (ρ = 0.08, P = 0.57). For lymphatic malformations, total lesion volume correlated with volume of macrocystic components (ρ = 0.47, P < 0.01). Total volume reduction significantly correlated with clinical response grade (ρ = 0.46, P = 0.02). For lymphatic malformations, reduction of volume of the macrocystic component significantly correlated with clinical response grade (ρ = 0.44, P = 0.03).Changes in calculated volume corresponded to clinical measures of treatment response. Variability of qualitative approaches to lesion analysis may have led to the lack of correlation between initial size of a lesion based on clinical measures and calculated volume. Future research should include quantitative metrics to augment qualitative clinical results.

    View details for DOI 10.1177/0284185115575779

    View details for PubMedID 25788316

  • Guidelines and parameters: percutaneous sclerotherapy for the treatment of head and neck venous and lymphatic malformations. Journal of neurointerventional surgery Heit, J. J., Do, H. M., Prestigiacomo, C. J., Delgado-Almandoz, J. A., English, J., Gandhi, C. D., Albequerque, F. C., Narayanan, S., Blackham, K. A., Abruzzo, T., Albani, B., Fraser, J. F., Heck, D. V., Hussain, M. S., Lee, S., Ansari, S. A., Hetts, S. W., Bulsara, K. R., Kelly, M., Arthur, A. S., Patsalides, A., Pride, G. L., Powers, C. J., Alexander, M. J., Meyers, P. M., Jayaraman, M. V. 2016

    View details for DOI 10.1136/neurintsurg-2015-012255

    View details for PubMedID 26801946

  • Use of thromboelastography to tailor dual-antiplatelet therapy in patients undergoing treatment of intracranial aneurysms with the Pipeline embolization device. Journal of neurointerventional surgery McTaggart, R. A., Choudhri, O. A., Marcellus, M. L., Brennan, T., Steinberg, G. K., Dodd, R. L., Do, H. M., Marks, M. P. 2015; 7 (6): 425-430


    Platelet function testing is controversial and not well studied in patients with neurovascular disease.To evaluate the performance of thromboelastography (TEG) as a platelet function test in neurovascular patients treated with the Pipeline embolization device (PED).A prospective protocol was instituted for platelet function testing in patients undergoing repair of intracranial aneurysms with the PED. All patients received dual antiplatelet therapy (DAT) and their response to both P2Y12 inhibitors and aspirin was quantified with TEG. Each patient's DAT induction strategy was tailored based on the percentage ADP-induced and percentage arachidonic acid-induced platelet inhibition reported by TEG. Data collected included clinical presentation, aneurysm characteristics, treatment details, and periprocedural events. Patients were followed up clinically and/or angiographically at 30 days, 6 months, and 1 year.Thirty-four PED procedures were performed on 31 patients. TEG results altered the DAT strategy in 35% of patients. Technical success with the Pipeline placement was 100%. Two patients had minor strokes and five had transient ischemic attacks (TIAs). There have been no hemorrhagic complications. No patient had permanent neurologic deficits. Six of eight (75%) of patients with thromboembolic/TIA events were ADP-induced hyporesponders by TEG. Our 6- and 12-month angiographic occlusion rates were 78.9% and 89.5%, respectively. The 19 major branches covered by the PED that were assessed by follow-up imaging have all remained patent.Platelet function testing with TEG altered our DAT induction strategy in a significant number of cases. No hemorrhagic or disabling thromboembolic complications were seen in this series. Future studies should compare methods of platelet function testing and, possibly, no platelet function testing in neurovascular patients undergoing flow diversion and/or stent-assisted treatment of intracranial aneurysms.

    View details for DOI 10.1136/neurintsurg-2013-011089

    View details for PubMedID 24739599

  • Effect of a Balloon-Expandable Intracranial Stent vs Medical Therapy on Risk of Stroke in Patients With Symptomatic Intracranial Stenosis The VISSIT Randomized Clinical Trial JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION Zaidat, O. O., Fitzsimmons, B., Woodward, B. K., Wang, Z., Killer-Oberpfalzer, M., Wakhloo, A., Gupta, R., Kirshner, H., Megerian, J. T., Lesko, J., Pitzer, P., Ramos, J., Castonguay, A. C., Barnwell, S., Smith, W. S., Gress, D. R. 2015; 313 (12): 1240-1248


    Intracranial stenosis is one of the most common etiologies of stroke. To our knowledge, no randomized clinical trials have compared balloon-expandable stent treatment with medical therapy in symptomatic intracranial arterial stenosis.To evaluate the efficacy and safety of the balloon-expandable stent plus medical therapy vs medical therapy alone in patients with symptomatic intracranial stenosis (≥70%).VISSIT (the Vitesse Intracranial Stent Study for Ischemic Stroke Therapy) trial is an international, multicenter, 1:1 randomized, parallel group trial that enrolled patients from 27 sites (January 2009-June 2012) with last follow-up in May 2013.Patients (N = 112) were randomized to receive balloon-expandable stent plus medical therapy (stent group; n = 59) or medical therapy alone (medical group; n = 53).a composite of stroke in the same territory within 12 months of randomization or hard transient ischemic attack (TIA) in the same territory day 2 through month 12 postrandomization. A hard TIA was defined as a transient episode of neurological dysfunction caused by focal brain or retinal ischemia lasting at least 10 minutes but resolving within 24 hours. Primary safety measure: a composite of any stroke, death, or intracranial hemorrhage within 30 days of randomization and any hard TIA between days 2 and 30 of randomization. Disability was measured with the modified Rankin Scale and general health status with the EuroQol-5D, both through month 12.Enrollment was halted by the sponsor after negative results from another trial prompted an early analysis of outcomes, which suggested futility after 112 patients of a planned sample size of 250 were enrolled. The 30-day primary safety end point occurred in more patients in the stent group (14/58; 24.1% [95% CI, 13.9%-37.2%]) vs the medical group (5/53; 9.4% [95% CI, 3.1%-20.7%]) (P = .05). Intracranial hemorrhage within 30 days occurred in more patients in the stent group (5/58; 8.6% [95% CI, 2.9%-19.0%]) vs none in the medical group (95% CI, 0%-5.5%) (P = .06). The 1-year primary outcome of stroke or hard TIA occurred in more patients in the stent group (21/58; 36.2% [95% CI, 24.0-49.9]) vs the medical group (8/53; 15.1% [95% CI, 6.7-27.6]) (P = .02). Worsening of baseline disability score (modified Rankin Scale) occurred in more patients in the stent group (14/58; 24.1% [95% CI, 13.9%-37.2%]) vs the medical group (6/53; 11.3% [95% CI, 4.3%-23.0%]) (P = .09).The EuroQol-5D showed no difference in any of the 5 dimensions between groups at 12-month follow-up.Among patients with symptomatic intracranial arterial stenosis, the use of a balloon-expandable stent compared with medical therapy resulted in an increased 12-month risk of added stroke or TIA in the same territory, and increased 30-day risk of any stroke or TIA. These findings do not support the use of a balloon-expandable stent for patients with symptomatic intracranial arterial Identifier: NCT00816166.

    View details for DOI 10.1001/jama.2015.1693

    View details for PubMedID 25803346

  • Development of arteriovenous fistula after revascularization bypass for Moyamoya disease: case report. Neurosurgery Feroze, A. H., Kushkuley, J., Choudhri, O., Heit, J. J., Steinberg, G. K., Do, H. M. 2015; 11: E202-6


    Moyamoya disease is a rare cerebrovascular disorder often treated by direct and indirect revascularization bypass techniques given a typically devastating disease course and poor response to medical therapy. In this report, we describe the formation and subsequent management of a de novo arteriovenous fistula identified in the setting of a patient treated with direct bypass surgery, a previously unreported phenomenon.A 51-year-old female presenting with Suzuki stage IV bilateral moyamoya disease underwent bilateral extracranial to intracranial (EC-IC) STA-MCA bypass without complication at our institution. At six-month follow-up, she demonstrated no evidence of residual neurologic deficits or continued symptoms despite documentation of an arteriovenous fistula arising at the site of the right EC-IC bypass upon routine follow-up cerebral angiography.We present the first reported case of de novo arteriovenous fistula formation following superficial temporal artery (STA) to middle cerebral artery (MCA) bypass for the treatment of moyamoya disease. Treatment of such iatrogenic arteriovenous fistulae fed by a patent bypass vessel may prove challenging without associated compromise of the bypass, meriting careful evaluation of all potential therapeutic options. The fistula herein most likely occurred secondary to recanalization of a previously thrombosed vein of Trolard. This case demonstrates the possibility of arteriovenous fistula formation as a potential sequela of revascularization bypass surgery and lends support to the previously described traumatic etiology of fistula formation.

    View details for DOI 10.1227/NEU.0000000000000558

    View details for PubMedID 25251198

  • Cerebral angioplasty using the Scepter XC dual lumen balloon for the treatment of vasospasm following intracranial aneurysm rupture JOURNAL OF NEUROINTERVENTIONAL SURGERY Heit, J. J., Choudhri, O., Marks, M. P., Dodd, R. L., Do, H. M. 2015; 7 (1): 56-61


    Cerebral vasospasm following subarachnoid hemorrhage (SAH) results in significant morbidity and mortality. Intra-arterial administration of calcium channel blockers or intracranial angioplasty may be performed when non-invasive medical management fails to prevent neurologic deterioration. Technical improvements in balloon catheters are expected to improve the success and safety of cerebral angioplasty.To describe our initial experience with the new Scepter XC balloon catheter in cerebral vasospasm treatment following SAH.All patients who underwent cerebral angioplasty using the Scepter XC balloon for the treatment of medically refractory cerebral vasospasm after SAH were identified. Patient demographic information, procedural details, and outcome were obtained from electronic medical records.Five consecutive patients undergoing vasospasm treatment with cerebral angioplasty using the Scepter XC were identified. All treated patients had medically refractory vasospasm that was moderate or severe. Angioplasty of the supraclinoid internal carotid artery, the A1 and A2 segments of the anterior cerebral artery, the M1 and M2 segments of the middle cerebral artery, the V4 segment of the vertebral artery, and the basilar artery was performed. All angioplasty procedures were technically successful, and the degree of vasospasm improved significantly following angioplasty. There were no complications related to the cerebral angioplasty procedures.The Scepter XC balloon catheter is safe and effective in the treatment of cerebral vasospasm following SAH. The excellent trackability and stability of the balloon catheter and the extra compliant design of the balloon represent technical advancements in the endovascular armamentarium in the treatment of cerebral vasospasm.

    View details for DOI 10.1136/neurintsurg-2013-011043

    View details for PubMedID 24385556

  • Percutaneous sclerotherapy with ethanolamine oleate for venous malformations of the head and neck. Journal of neurointerventional surgery Alexander, M. D., McTaggart, R. A., Choudhri, O. A., Marcellus, M. L., Do, H. M. 2014; 6 (9): 695-698


    Venous malformations frequently occur in the head and neck, and they can require treatment for a variety of reasons. Among multiple therapeutic approaches employed, percutaneous sclerotherapy has become one of the most commonly used treatments, with numerous sclerosants successfully utilized. Ethanolamine oleate has approval from the Food and Drug Administration for sclerosis of esophageal varices, and is used by some practitioners for the treatment of venous malformations. This study reports single center results of percutaneous sclerotherapy with ethanolamine oleate to treat venous malformations of the head and neck.Prospectively maintained procedural records were retrospectively reviewed to identify all patients with venous malformations who underwent percutaneous sclerotherapy. The Mulliken and Glowacki classification was used to diagnose venous malformations. Medical records and images were reviewed to record demographic information, lesion characteristics, treatment sessions, and clinical and imaging response. Quantitative volumetric analysis was conducted to augment commonly used poorly reproducible subjective outcome measures. Response was assessed after each session and completion of all percutaneous treatment. A χ(2) analysis was performed to evaluate the effects of the above described characteristics on outcomes.52 interventions were performed for lesions in 26 patients. No complications occurred following any procedures. Response to individual sessions was categorized as excellent following two (3.8%) sessions, good following 45 (86.5%), and fair following four (7.7%) session. No sessions resulted in poor responses. Final results were excellent in two patients (7.7%), good in 22 (84.6%), and fair in two (7.7%). Average lesion volume reduction was 39% following each session, and 61% after treatment completion. Periorbital lesions were significantly less likely than lesions located elsewhere to have good or excellent outcomes. No other lesion or demographic features affected outcomes.Percutaneous sclerotherapy with ethanolamine oleate appears to be safe and effective for the treatment of venous malformations and should be considered when treating these complex lesions. The efficacy of this agent appears to match or exceed that of other sclerosants used for such treatment, and further investigation in prospective controlled research is warranted.

    View details for DOI 10.1136/neurintsurg-2013-010924

    View details for PubMedID 24235099

  • Percutaneous sclerotherapy with ethanolamine oleate for lymphatic malformations of the head and neck. Journal of neurointerventional surgery Alexander, M. D., McTaggart, R. A., Choudhri, O. A., Marcellus, M. L., Do, H. M. 2014; 6 (9): 691-694


    Lymphatic malformations are low flow congenital lesions that frequently occur in the head and neck, and often require treatment. Multiple therapeutic modalities exist, including percutaneous sclerotherapy, which has been performed successfully with numerous sclerosants. Few data exist on use of ethanolamine oleate to treat lymphatic malformations. This study reports single center results using this agent to treat lymphatic malformations of the head and neck.Prospectively maintained procedural records were retrospectively reviewed to identify all patients with lymphatic malformations who underwent percutaneous sclerotherapy. The Mulliken and Glowacki classification was used to diagnose lymphatic malformations. Medical records and images were reviewed to record demographic information, lesion characteristics, treatment sessions, and clinical and imaging response. Lesions and outcomes were evaluated with both qualitative and quantitative volumetric analysis. Response was assessed after each session and after all sessions in those patients undergoing more than one intervention, and χ(2) analysis was performed to evaluate the effects of lesion and demographic characteristics on outcomes.12 interventions were performed for lesions in 10 patients. No procedural complications occurred following any procedures. Four (40.0%) patients had an excellent result after treatment, which was accomplished in one session for each of these lesions. Four (40.0%) had good results. One (10.0%) had a fair result after three sessions. One (10.0%) patient with an indeterminate syndrome with multiple congenital anomalies had a poor response following treatment. The family decided to withdraw care, and the airway was compromised. Average lesion volume reduction was 28% for all lesions and 42% when excluding the lesion for which future treatments were declined. Purely macrocystic lesions were more likely to have an excellent response to treatment than lesions with both macrocystic and microcystic components.Percutaneous sclerotherapy using ethanolamine oleate to treat lymphatic malformations of the head and neck appears safe and efficacious. This agent should be considered when treating these complex lesions, particularly those that are exclusively macrocystic. Further investigation of such treatments should evaluate this agent alongside the many others currently utilized.

    View details for DOI 10.1136/neurintsurg-2013-010925

    View details for PubMedID 24153336

  • Platelet function inhibitors and platelet function testing in neurointerventional procedures JOURNAL OF NEUROINTERVENTIONAL SURGERY Gandhi, C. D., Bulsara, K. R., Fifi, J., Kass-Hout, T., Grant, R. A., Almandoz, J. E., English, J., Meyers, P. M., Abruzzo, T., Prestigiacomo, C. J., Powers, C. J., Lee, S., Albani, B., Do, H. M., Eskey, C. J., Patsalides, A., Hetts, S., Hussain, M. S., Ansari, S. A., Hirsch, J. A., Kelly, M., Rasmussen, P., Mack, W., Pride, G. L., Alexander, M. J., Jayaraman, M. V. 2014; 6 (8): 567-577

    View details for DOI 10.1136/neurintsurg-2014-011357

    View details for PubMedID 25056369

  • Multimodality evaluation of dural arteriovenous fistula with CT angiography, MR with arterial spin labeling, and digital subtraction angiography: case report. Journal of neuroimaging Alexander, M., McTaggart, R., Santarelli, J., Fischbein, N., Marks, M., Zaharchuk, G., Do, H. 2014; 24 (5): 520-523


    Dural arteriovenous fistulae (DAVF) are cerebrovascular lesions with pathologic shunting into the venous system from arterial feeders. Digital subtraction angiography (DSA) has long been considered the gold standard for diagnosis, but advances in noninvasive imaging techniques now play a role in the diagnosis of these complex lesions. Herein, we describe the case of a patient with right-side pulsatile tinnitus and DAVF diagnosed using computed tomography angiography, magnetic resonance with arterial spin labeling, and DSA. Implications for imaging analysis of DAVFs and further research are discussed.

    View details for DOI 10.1111/jon.12032

    View details for PubMedID 23746119

  • Endovascular reconstruction of enlarging traumatic internal carotid artery pseudoaneurysm. Neurosurgical focus Choudhri, O., Heit, J., Do, H. M. 2014; 37 (1): 1-?


    Traumatic dissecting pseudoaneurysms of the cervical and petrous internal carotid artery are often a result of blunt or penetrating trauma. These patients are at high risk for thromboembolic complications and are managed with antiplatelet agents. Patients who develop neurologic symptoms while on antiplatelet agents, or have interval enlargement of their pseudoaneurysms, may require repair of the vessel. We describe a case in which we performed an endovascular repair of an enlarging distal cervical internal carotid artery pseudoaneurysm, with placement of a covered stent. The video can be found here: .

    View details for DOI 10.3171/2014.V2.FOCUS14185

    View details for PubMedID 24983722

  • Endovascular treatment of a tentorial dural arteriovenous fistula. Neurosurgical focus Choudhri, O., Marks, M. P. 2014; 37 (1): 1-?


    Tentorial dural arteriovenous fistulae are rare intracranial fistulae, in which the fistula pocket is present within the leaves of tentorium cerebelli. These tentorial fistulae can be rarely present near the galenic complex, where they can engorge the deep venous system and cause symptoms of venous hypertension. We present an interesting case of endovascular treatment of a galenic tentorial dural arteriovenous fistula in a patient with headaches and imbalance. The fistula was accessed through the artery of Davidoff and Schecter from the posterior cerebral artery supplying the fistula. The fistula was completely embolized using Onyx and with preservation of vein of Galen. The video can be found here: .

    View details for DOI 10.3171/2014.V2.FOCUS14184

    View details for PubMedID 24983732

  • E-012 national trends for the utilization of cerebral angiography in patients with unruptured aneurysms: 1999-2009. Journal of neurointerventional surgery Choudhri, O., Feroze, A., Mantha, A., Steinberg, G., Do, H. 2014; 6: A43-?


    The utilization of cerebral angiography in the diagnosis and management of patients with unruptured cerebral aneurysms varies across the United States. Given advances in noninvasive imaging, such as CT and MR angiography, patients with unruptured aneurysms may never undergo cerebral angiography. This study explores shifting trends in the utilization of angiography for management of such lesions across the U. S. from 1999-2009.The National Inpatient Sample was used to identify patients carrying a primary ICD-9 diagnosis code of unruptured aneurym (430.0) between 1999-2009. The primary outcomes were compared across subgroups undergoing cerebral angiography in the management of their pathology versus those who did not. The data were analyzed using univariate and multivariate regression (SAS).There were 127579 total admissions with a primary ICD-9 diagnosis of unruptured aneurysms between 1999-2009 per NIS weighted estimates. The total number of patients who underwent cerebral angiography and subsequent clipping were 19412 between 1999-2009. During the same time period 28095 patients underwent coiling after cerebral angiography. For the year 1999, 77% patients were clipped and 23% coiled after cerebral angiography (p < 0.0001). Conversely for the year 2009, 29% patients were clipped and 71% coiled after cerebral angiography (p < 0.0001). These trends were less pronounced though significant in the patients who did not undergo initial cerebral angiography, such that for the year 1999, 88% patients with unruptured aneurysms were clipped while only 12% were coiled.Patients with unruptured cerebral aneuryms who undergo cerebral angiography are more likely to undergo endovascular coiling rather than clipping.O. Choudhri: None. A. Feroze: None. A. Mantha: None. G. Steinberg: None. H. Do: None.

    View details for DOI 10.1136/neurintsurg-2014-011343.79

    View details for PubMedID 25064927

  • O-034 Carotid Artery Angioplasty versus Stenting in Acute Ischemic Stroke. Journal of neurointerventional surgery Choudhri, O., Gupta, M., Feroze, A., Albers, G., Lansberg, M., Do, H., Dodd, R., Marcellus, M., Marks, M. 2014; 6: A18-9


    Acute ischemic stroke secondary to cervical carotid artery occlusion can lead to significant morbidity and mortality. Acute carotid occlusion may be managed by carotid angioplasty, stenting, or both. The use of carotid stents requires patients to be placed on dual antiplatelet agents, which may contribute to increased haemorrhage risk. We undertook this study to evaluate outcomes for angioplasty alone versus stenting in the setting of acute carotid occlusion.All patients treated from 2008 to 2013 with acute cervical internal carotid artery occlusions that had intervention within eight hours of symptom onset were included. NIHSS were recorded preceding intervention, and clinical outcomes were assessed using mRS at 90 days. All imaging and angiographic data were reviewed for pre-procedural ASPECT scores, pre- and post- TICI reperfusion scores, and intracranial haemorrhage as defined by PH grading score for haemorrhage. Demographic and treatment factors were correlated with good functional outcome (mRS < 2 at 90 days and a comparison was made for patients undergoing angioplasty alone versus stenting. All patients who underwent carotid stent were placed on dual antiplatelet agents while angioplasty patients received aspirin only.Twenty-four patients (15 males, 9 females; mean age, 67 years) satisfied the inclusion criteria. Seventeen patients underwent placement of carotid stent and 7 patients had angioplasty alone. Patients in both subgroups were comparable across characteristics including comorbidities, time for onset to recanalization, ASPECTS, and IV tPA use. 35% of patients who underwent stenting had good functional outcomes, versus 71% of patients treated with angioplasty alone, although these differences were not statistically significant. No differences were seen for the two treatment groups comparing time from onset to recanalization, baseline ASPECTS, and IV tPA use. Additionally, increased age (p = 0.049) and post-treatment parenchymal haemorrhage- PH1 or PH2 (p = 0.016) correlated with poor outcomes (mRS > 2). All parenchymal haemorrhages (6/17) and deaths (5/17) fell within the stenting subgroup (35.3% and 29.4%, respectively).This data suggest that patients undergoing angioplasty alone in the setting of acute internal carotid artery occlusion may have improved functional outcome at 90-day compared to those undergoing stenting. This study was limited by a small sample size and a larger study would be needed to confirm these findings.angioplasty, stenting, acute ischemic stroke, carotid occlusion.O. Choudhri: None. M. Gupta: None. A. Feroze: None. G. Albers: None. M. Lansberg: None. H. Do: None. R. Dodd: None. M. Marcellus: None. M. Marks: None.

    View details for DOI 10.1136/neurintsurg-2014-011343.34

    View details for PubMedID 25064877

  • E-013 endovascular management of pseudoaneurysms secondary to external ventricular drain placement: single center experience. Journal of neurointerventional surgery Choudhri, O., Gupta, M., Heit, J., Feroze, A., Do, H. 2014; 6: A43-4


    Placement of external ventricular drains is a common, life-saving neurosurgical procedure indicated across a variety of settings. While advances have made the procedure quite safe, the potential for iatrogenic morbidity and mortality continues. Herein, we document our experience with the endovascular management of three pseudoaneurysms associated with EVD placement.We performed a retrospective analysis to identify all EVDs placed from 2008 through 2013 at our institution,. In instances of EVD-associated cerebrovascular injury, all admission and subsequent radiographic studies were reviewed, including cerebral angiograms and computed tomography (CT) scans. Angiograms were reviewed to record the extent of vascular injury and angiographic outcomes after treatment.One female and two male patients (40-75 years) were found to have developed vascular injuries associated with EVD placement. Three pseudoaneurysms, namely of the posterior communicating artery (PCOM), pericallosal artery branch and the middle meningeal artery, were treated by coil and/or glue embolization.Although EVD-associated cerebrovascular injury remains a rare phenomenon, such procedures are not entirely benign. Endovascular repair for such lesions proves a viable, effective option.arteriovenous fistula (AVF), computed tomography (CT), external ventricular drain (EVD), posterior communicating artery (PCOM), posterior cerebral artery (PCA) DISCLOSURES: O. Choudhri: None. M. Gupta: None. J. Heit: None. A. Feroze: None. H. Do: None.

    View details for DOI 10.1136/neurintsurg-2014-011343.80

    View details for PubMedID 25064928

  • Endovascular management of cerebral venous sinus thrombosis. Neurosurgical focus Choudhri, O., Feroze, A., Marks, M. P., Do, H. M. 2014; 37 (1): 1-?


    Cerebral venous sinus thrombosis (CVST) is characterized by formation of widespread thrombus within the cerebral venous sinus system. CVST can cause venous hypertension, venous infarcts, hemorrhage and seizures. It is managed in most cases with systemic anticoagulation through the use of heparin to resolve the thrombus. Patients that demonstrate clinical deterioration while on heparin are often treated with endovascular strategies to recanalize the sinuses. We present the case of a patient with widespread CVST, involving his superior sagittal sinuses and bilateral transverse sigmoid sinuses, who was treated with a combination of endovascular therapies. The video can be found here: .

    View details for DOI 10.3171/2014.V2.FOCUS14186

    View details for PubMedID 24983720

  • Prospective pilot investigation of 18F-NaF PET/CT for identification of thoracolumbar compression fractures amenable to vertebroplasty Do, H., Dodd, R., Guo, H., Quon, A. SOC NUCLEAR MEDICINE INC. 2014
  • Standards of practice and reporting standards for carotid artery angioplasty and stenting JOURNAL OF NEUROINTERVENTIONAL SURGERY Powers, C. J., Hirsch, J. A., Hussain, M. S., Patsalides, A. T., Blackham, K. A., Narayanan, S., Lee, S., Fraser, J. F., Bulsara, K. R., Prestigiacomo, C. J., Gandhi, C. D., Abruzzo, T., Do, H. M., Meyers, P. M., Albuquerque, F. C., Frei, D., Kelly, M. E., Pride, G. L., Jayaraman, M. V. 2014; 6 (2): 87-90
  • Endovascular management of external ventricular drain-associated cerebrovascular injuries. Surgical neurology international Choudhri, O., Gupta, M., Feroze, A. H., Heit, J. J., Do, H. M. 2014; 5: 167-?


    Placement of external ventricular drains (EVDs) is a common, life-saving neurosurgical procedure indicated across a variety of settings. While advances have made the procedure quite safe, the potential for iatrogenic morbidity and mortality continues. We document our experience with the endovascular management of three pseudoaneurysms associated with EVD placement and discuss the endovascular treatment options for EVD-associated cerebrovascular injury.We performed a retrospective analysis to identify all EVDs placed from 2008 through 2013 at our institution. In instances of EVD-associated cerebrovascular injury, all admission and subsequent radiographic studies were reviewed, including cerebral angiograms and computed tomography (CT) scans where available. Angiograms were reviewed to record the extent of vascular injury and outcomes after treatment.One female and two male patients (age range, 40-75 years) were found to have developed vascular injuries associated with EVD placement. Three pseudoaneurysms, of the posterior communicating artery (PCOM), pericallosal artery branch, and the middle meningeal artery, respectively, were treated by coil and/or glue embolization.Although EVD-associated cerebrovascular injury remains a rare phenomenon, such procedures are not entirely benign. Endovascular repair for such lesions proves a viable, effective option.

    View details for DOI 10.4103/2152-7806.145930

    View details for PubMedID 25558425

  • Vertebral augmentation: report of the Standards and Guidelines Committee of the Society of NeuroInterventional Surgery. Journal of neurointerventional surgery Chandra, R. V., Meyers, P. M., Hirsch, J. A., Abruzzo, T., Eskey, C. J., Hussain, M. S., Lee, S., Narayanan, S., Bulsara, K. R., Gandhi, C. D., Do, H. M., Prestigiacomo, C. J., Albuquerque, F. C., Frei, D., Kelly, M. E., Mack, W. J., Pride, G. L., Jayaraman, M. V. 2014; 6 (1): 7-15

    View details for DOI 10.1136/neurintsurg-2013-011012

    View details for PubMedID 24198272

  • Reversible cerebral vasoconstriction syndrome and bilateral vertebral artery dissection presenting in a patient after cesarean section. Journal of neurointerventional surgery Mitchell, L. A., Santarelli, J. G., Singh, I. P., Do, H. M. 2014; 6 (1)


    Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by sudden-onset thunderclap headache and focal neurologic deficits. Once thought to be a rare syndrome, more advanced non-invasive imaging has led to an increase in RCVS diagnosis. Unilateral vertebral artery dissection has been described in fewer than 40% of cases of RCVS. Bilateral vertebral artery dissection has rarely been reported. We describe the case of a patient with RCVS and bilateral vertebral artery dissection presenting with an intramedullary infarct treated successfully with medical management and careful close follow-up. This rare coexistence should be recognized as the treatment differs.

    View details for DOI 10.1136/neurintsurg-2012-010521.rep

    View details for PubMedID 24415454

  • Reporting standards for endovascular chemotherapy of head, neck and CNS tumors JOURNAL OF NEUROINTERVENTIONAL SURGERY Fraser, J. F., Hussain, M. S., Eskey, C., Abruzzo, T., Bulsara, K., English, J., Blackham, K., Do, H. M., Prestigiacomo, C., Jayaraman, M. V., Patsalides, A., Kelly, M., Sunshine, J. L., Meyers, P. 2013; 5 (5): 396-399


    The goal of this article is to provide expert consensus recommendations for reporting standards, terminology and definitions when reporting on neurointerventional chemotherapy administration for head and neck tumors. These criteria may be used to design clinical trials, to provide definitions for patient stratification and to permit robust analysis of published data.This publication represents a consensus document by the Society for Neurointerventional Surgery. A PubMed search was conducted and included articles published in 2002-2011, with the search strategy designed to identify all studies of intra-arterial chemotherapy for tumors of neck and head. Articles were evaluated for evidence class, and recommendations were made using guidelines for evidence-based medicine proposed by a joint committee of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons. Specifically, technical methods, outcome variables and reported complications were highlighted.Thirty-five publications were included in the review. While most studies represent class III evidence, there was sufficient concordance to justify level 2 recommendations regarding technical methods for administration of intra-arterial chemotherapy. The data also support level 2 recommendations regarding reporting of particular outcome variables subsumed within broad categories entitled 'Procedure-related', 'Disease control' and 'Survival'. The data support recommendations for the reporting of access site-related, neurologic, head and neck, ocular, hematologic and systemic complications, and also complications related to the percutaneous access site.Intra-arterial chemotherapy is a growing field in interventional neuroradiology. It is important to adopt uniform technical and reporting standards that will allow cross-publication comparisons and facilitate homogeneous practice standards. Published data support such standards, which are vital for the consistent evaluation of future published research.

    View details for DOI 10.1136/neurintsurg-2013-010841

    View details for Web of Science ID 000323168700017

    View details for PubMedID 23828325

  • Delayed Retraction of the Pipeline Embolization Device and Corking Failure: Pitfalls of Pipeline Embolization Device Placement in the Setting of a Ruptured Aneurysm NEUROSURGERY McTaggart, R. A., Santarelli, J. G., Marcelus, M. L., Steinberg, G. K., Dodd, R. L., Do, H. M., Marks, M. P. 2013; 72 (6): 237-237


    : The safety of flow-diverting stents for the treatment of ruptured intracranial aneurysms is unknown.: A 35-year-old woman with a ruptured dissecting aneurysm of the intradural right vertebral artery and incorporating the right posterior inferior cerebellar artery was treated with a Pipeline Embolization Device (PED). Five days after reconstruction of the diseased right vertebral segment, she was treated for vasospasm, and retraction of the PED was observed, leaving her dissecting aneurysm unprotected. A second PED was placed with coverage of the aneurysm, but vasospasm complicated optimal positioning of the device.: In addition to the potential risks of dual antiplatelet therapy in these patients, this case illustrates 2 pitfalls of flow-diverting devices in vessels in vasospasm: delayed retraction of the device and difficulty positioning the device for deployment in the setting of vasospasm.: ANR, aneurysmPED, Pipeline Embolization DevicePICA, posterior inferior cerebellar arterySAH, subarachnoid hemorrhage.

    View details for DOI 10.1227/NEU.0b013e31827fc9be

    View details for Web of Science ID 000319535100029

  • Reversible cerebral vasoconstriction syndrome and bilateral vertebral artery dissection presenting in a patient after cesarean section. BMJ case reports Mitchell, L. A., Santarelli, J. G., Singh, I. P., Do, H. M. 2013; 2013


    Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by sudden-onset thunderclap headache and focal neurologic deficits. Once thought to be a rare syndrome, more advanced non-invasive imaging has led to an increase in RCVS diagnosis. Unilateral vertebral artery dissection has been described in fewer than 40% of cases of RCVS. Bilateral vertebral artery dissection has rarely been reported. We describe the case of a patient with RCVS and bilateral vertebral artery dissection presenting with an intramedullary infarct treated successfully with medical management and careful close follow-up. This rare coexistence should be recognized as the treatment differs.

    View details for DOI 10.1136/bcr-2012-010521

    View details for PubMedID 23354867

  • Standard of practice: embolization of ruptured and unruptured intracranial aneurysms. Journal of neurointerventional surgery Patsalides, A. n., Bulsara, K. R., Hsu, D. P., Abruzzo, T. n., Narayanan, S. n., Jayaraman, M. V., Duckwiler, G. n., Klucznik, R. P., Kelly, M. n., Hirsch, J. A., Heck, D. n., Sunshine, J. n., Frei, D. n., Alexander, M. J., Do, H. M., Meyers, P. M. 2013; 5 (4): 283–88

    View details for DOI 10.1136/neurintsurg-2012-010645

    View details for PubMedID 23576604

  • A Simplified Method for Administration of Intra-Arterial Nicardipine for Vasospasm With Cervical Catheter Infusion NEUROSURGERY Pandey, P., Steinberg, G. K., Dodd, R., Do, H. M., Marks, M. P. 2012; 71: 77-85


    Cerebral vasospasm is a major cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage. Nicardipine has previously been used to treat vasospasm through superselective intracranial microcatheter injections.To evaluate a simple method of treatment of vasospasm with slow infusion of nicardipine from a cervical catheter.Twenty-seven patients with symptomatic vasospasm were treated over 4 years with cervical catheter infusions. Nicardipine was infused at 20 mg/h for 30 to 60 minutes. Angioplasty was used in severe cases at the operator's discretion. Outcome at discharge and follow-up was evaluated with Glasgow Outcome Scale.Twenty-seven patients (17 women, 12 men) received intra-arterial therapy for vasospasm. Vasospasm treatment was done at a mean post-hemorrhage date of 7.2 days (range, 4-15 days). They underwent 48 sessions of treatment (mean, 1.8 per patient) in 72 separate arterial territories. Twelve patients underwent multiple treatments. The mean dose used per session was 19.2 mg (range, 5-50 mg). Four patients underwent angioplasty for severe vasospasm. Twenty-two patients (81.5%) had clinical improvement after the infusion. Angiographic improvement was seen in 86.1% of the vessels analyzed, which had moderate or severe spasm before infusion. Overall, 17 patients (62.9%) had good outcome (Glasgow Outcome Scale score, 4 and 5) at discharge, 11 had poor outcome, and 1 patient died. Follow-up was available in 19 patients, and 18 were doing well (Glasgow Outcome Scale score, 4 and 5).Intra-arterial nicardipine is an effective and safe treatment for cerebral vasospasm. In most patients, infusion can be performed from the cervical catheter, with microcatheter infusion and angioplasty reserved for the more severe and resistant cases.

    View details for DOI 10.1227/NEU.0b013e3182426257

    View details for PubMedID 22105209

  • Head, neck, and brain tumor embolization guidelines JOURNAL OF NEUROINTERVENTIONAL SURGERY Duffis, E. J., Gandhi, C. D., Prestigiacomo, C. J., Abruzzo, T., Albuquerque, F., Bulsara, K. R., Derdeyn, C. P., Fraser, J. F., Hirsch, J. A., Hussain, M. S., Do, H. M., Jayaraman, M. V., Meyers, P. M., Narayanan, S. 2012; 4 (4): 251-255


    Management of vascular tumors of the head, neck, and brain is often complex and requires a multidisciplinary approach. Peri-operative embolization of vascular tumors may help to reduce intra-operative bleeding and operative times and have thus become an integral part of the management of these tumors. Advances in catheter and non-catheter based techniques in conjunction with the growing field of neurointerventional surgery is likely to expand the number of peri-operative embolizations performed. The goal of this article is to provide consensus reporting standards and guidelines for embolization treatment of vascular head, neck, and brain tumors.This article was produced by a writing group comprised of members of the Society of Neurointerventional Surgery. A computerized literature search using the National Library of Medicine database (Pubmed) was conducted for relevant articles published between 1 January 1990 and 31 December 2010. The article summarizes the effectiveness and safety of peri-operative vascular tumor embolization. In addition, this document provides consensus definitions and reporting standards as well as guidelines not intended to represent the standard of care, but rather to provide uniformity in subsequent trials and studies involving embolization of vascular head and neck as well as brain tumors.Peri-operative embolization of vascular head, neck, and brain tumors is an effective and safe adjuvant to surgical resection. Major complications reported in the literature are rare when these procedures are performed by operators with appropriate training and knowledge of the relevant vascular and surgical anatomy. These standards may help to standardize reporting and publication in future studies.

    View details for DOI 10.1136/neurintsurg-2012-010350

    View details for Web of Science ID 000306026400006

    View details for PubMedID 22539531

    View details for PubMedCentralID PMC3370378

  • Multimodality management of Spetzler-Martin Grade III arteriovenous malformations JOURNAL OF NEUROSURGERY Pandey, P., Marks, M. P., Harraher, C. D., Westbroek, E. M., Chang, S. D., Do, H. M., Levy, R. P., Dodd, R. L., Steinberg, G. K. 2012; 116 (6): 1279-1288


    Grade III arteriovenous malformations (AVMs) are diverse because of their variations in size (S), location in eloquent cortex (E), and presence of central venous drainage (V). Because they may have implications for management and outcome, the authors evaluated these variations in the present study.Between 1984 and 2010, 100 patients with Grade III AVMs were treated. The AVMs were categorized by Spetzler-Martin characteristics as follows: Type 1 = S1E1V1, Type 2 = S2E1V0, Type 3 = S2E0V1, and Type 4 = S3E0V0. The occurrence of a new neurological deficit, functional status (based on modified Rankin Scale [mRS] score) at discharge and follow-up, and radiological obliteration were correlated with demographic and morphological characteristics.One hundred patients (49 female and 51 male; age range 5-68 years, mean 35.8 years) were evaluated. The size of AVMs was less than 3 cm in 28 patients, 3-6 cm in 71, and greater than 6 cm in 1; 86 AVMs were located in eloquent cortex and 38 had central drainage. The AVMs were Type 1 in 28 cases, Type 2 in 60, Type 3 in 11, and Type 4 in 1. The authors performed embolization in 77 patients (175 procedures), surgery in 64 patients (74 surgeries), and radiosurgery in 49 patients (44 primary and 5 postoperative). The mortality rate following the management of these AVMs was 1%. Fourteen patients (14%) had new neurological deficits, with 5 (5%) being disabling (mRS score > 2) and 9 (9%) being nondisabling (mRS score ≤ 2) events. Patients with Type 1 AVMs (small size) had the best outcome, with 1 (3.6%) in 28 having a new neurological deficit, compared with 72 patients with larger AVMs, of whom 13 (18.1%) had a new neurological deficit (p < 0.002). Older age (> 40 years), malformation size > 3 cm, and nonhemorrhagic presentation predicted the occurrence of new deficits (p < 0.002). Sex, eloquent cortex, and venous drainage did not confer any benefit. In 89 cases follow-up was adequate for data to be included in the obliteration analysis. The AVM was obliterated in 78 patients (87.6%), 69 of them (88.5%) demonstrated on angiography and 9 on MRI /MR angiography. There was no difference between obliteration rates between different types of AVMs, size, eloquence, and drainage. Age, sex, and clinical presentation also did not predict obliteration.Multimodality management of Grade III AVMs results in a high rate of obliteration, which was not influenced by size, venous drainage, or eloquent location. However, the development of new neurological deficits did correlate with size, whereas eloquence and venous drainage did not affect the neurological complication rate. The authors propose subclassifying the Grade III AVMs according to their size (< 3 and ≥ 3 cm) to account for treatment risk.

    View details for DOI 10.3171/2012.3.JNS111575

    View details for PubMedID 22482792

  • F18 NaF PET/CT of the spine for the pre-interventional evaluation of back pain Guo, H., Dodd, R., Huy Do, Quon, A. SOC NUCLEAR MEDICINE INC. 2012
  • Vascular tortuosity: modeling using optimality analysis Hathout, L., Do, H. FEDERATION AMER SOC EXP BIOL. 2012
  • Vascular tortuosity: a mathematical modeling perspective JOURNAL OF PHYSIOLOGICAL SCIENCES Hathout, L., Do, H. M. 2012; 62 (2): 133-145


    Although vascular tortuosity is a ubiquitous phenomenon, almost no mathematical models exist to describe its shape. Given that the shape of tortuous vessel curves seems fairly uniform across orders of magnitude of vessel size and across vast differences in anatomic substrata, it is hypothesized that the shape of tortuosity is not purely random but rather is governed by physical principles. We present a mathematical model of tortuosity based on optimality principles, and show how this model can potentially be used to distinguish physiologic tortuosity from abnormal tortuosity which may exist in disease states. Using the calculus of variations, a model of tortuosity has been developed which minimizes average curvature per unit length. The model is tested against curves in normal vessels and in diseased vessels in a case of Fabry's disease. It is found that the theoretical model provides a good fit for normal vessel tortuosity. This suggests that blood vessels obey optimality principles, and curve in such a way as to minimize average curvature. The model may also be able to distinguish physiologic tortuosity from abnormal tortuosity found in disease states.

    View details for DOI 10.1007/s12576-011-0191-6

    View details for Web of Science ID 000300774300006

    View details for PubMedID 22252461

  • Management of Pediatric Intracranial Arteriovenous Malformations: Experience With Multimodality Therapy NEUROSURGERY Darsaut, T. E., Guzman, R., Marcellus, M. L., Edwards, M. S., Tian, L., Do, H. M., Chang, S. D., Levy, R. P., Adler, J. R., Marks, M. P., Steinberg, G. K. 2011; 69 (3): 540-556


    Successful management of pediatric arteriovenous malformations (AVMs) often requires a balanced application of embolization, surgery, and radiosurgery.To describe our experience treating pediatric AVMs.We analyzed 120 pediatric patients (< 18 years of age) with AVMs treated with various combinations of radiosurgery, surgery, and endovascular techniques.Between 1985 and 2009, 76 children with low Spetzler-Martin grade (1-3) and 44 with high-grade (4-5) AVMs were treated. Annual risk of hemorrhage from presentation to initial treatment was 4.0%, decreasing to 3.2% after treatment initiation until confirmed obliteration. Results for AVM obliteration were available in 101 patients. Initial single-modality therapy led to AVM obliteration in 51 of 67 low-grade (76%) and 3 of 34 high-grade (9%) AVMs, improving to 58 of 67 (87%) and 9 of 34 (26%), respectively, with further treatment. Mean time to obliteration was 1.8 years for low-grade and 6.4 years for high-grade AVMs. Disabling neurological complications occurred in 4 of 77 low-grade (5%) and 12 of 43 high-grade (28%) AVMs. At the final clinical follow-up (mean, 9.2 years), 48 of 67 patients (72%) with low-grade lesions had a modified Rankin Scale score (mRS) of 0 to 1 compared with 12 of 34 patients (35%) with high-grade AVMs. On multivariate analysis, significant risk factors for poor final clinical outcome (mRS ≥ 2) included baseline mRS ≥ 2 (odds ratio, 9.51; 95% confidence interval, 3.31-27.37; P < .01), left-sided location (odds ratio, 3.03; 95% confidence interval, 1.11-8.33; P = .03), and high AVM grade (odds ratio, 4.35; 95% confidence interval, 1.28-14.28; P = .02).Treatment of pediatric AVMs with multimodality therapy can substantially improve obliteration rates and may decrease AVM hemorrhage rates. The poor natural history and risks of intervention must be carefully considered when deciding to treat high-grade pediatric AVMs.

    View details for DOI 10.1227/NEU.0b013e3182181c00

    View details for PubMedID 21430584

  • Arterial Spin-Labeling MRI Can Identify the Presence and Intensity of Collateral Perfusion in Patients With Moyamoya Disease STROKE Zaharchuk, G., Do, H. M., Marks, M. P., Rosenberg, J., Moseley, M. E., Steinberg, G. K. 2011; 42 (9): 2485-U183


    Determining the presence and adequacy of collateral blood flow is important in cerebrovascular disease. Therefore, we explored whether a noninvasive imaging modality, arterial spin labeling (ASL) MRI, could be used to detect the presence and intensity of collateral flow using digital subtraction angiography (DSA) and stable xenon CT cerebral blood flow as gold standards for collaterals and cerebral blood flow, respectively.ASL and DSA were obtained within 4 days of each other in 18 patients with Moyamoya disease. Two neurointerventionalists scored DSA images using a collateral grading scale in regions of interest corresponding to ASPECTS methodology. Two neuroradiologists similarly scored ASL images based on the presence of arterial transit artifact. Agreement of ASL and DSA consensus scores was determined, including kappa statistics. In 15 patients, additional quantitative xenon CT cerebral blood flow measurements were performed and compared with collateral grades.The agreement between ASL and DSA consensus readings was moderate to strong, with a weighted kappa value of 0.58 (95% confidence interval, 0.52-0.64), but there was better agreement between readers for ASL compared with DSA. Sensitivity and specificity for identifying collaterals with ASL were 0.83 (95% confidence interval, 0.77-0.88) and 0.82 (95% confidence interval, 0.76-0.87), respectively. Xenon CT cerebral blood flow increased with increasing DSA and ASL collateral grade (P<0.05).ASL can noninvasively predict the presence and intensity of collateral flow in patients with Moyamoya disease using DSA as a gold standard. Further study of other cerebrovascular diseases, including acute ischemic stroke, is warranted.

    View details for DOI 10.1161/STROKEAHA.111.61646

    View details for PubMedID 21799169

  • Intraoperative Angiography for Cranial Dural Arteriovenous Fistula AMERICAN JOURNAL OF NEURORADIOLOGY Pandey, P., Steinberg, G. K., Westbroek, E. M., Dodd, R., Do, H. M., Marks, M. P. 2011; 32 (6): 1091-1095


    IA is a valuable adjunct during surgery for a variety of neurovascular diseases; however, there are no reported series describing IA for DAVFs. This study was undertaken to evaluate the safety and efficacy of IA for DAVFs.A retrospective review of DAVF surgical cases during a 20-year period was conducted, and cases with IA were evaluated. Clinical details, surgical and angiographic findings, and postoperative outcomes were reviewed. The incidence of residual fistula on IAs, the utility of the surgical procedure, and the incidence of false-negative findings on IA were also determined.IA was performed in 29 patients (31 DAVFs) for DAVFs. The distribution of the fistulas was the following: transverse-sigmoid (n = 9), tentorial (n = 6), torcular (n = 3), cavernous sinus (n = 4), SSS (n = 4), foramen magnum (n = 3), and temporal-middle fossa (n = 2). Twelve patients had undergone prior embolization, while 6 patients had unsuccessful embolization procedures. Thirty-eight surgeries were performed for DAVF in 29 patients, and IA was performed in 34 surgeries. Forty-four angiographic procedures were performed in the 34 surgeries. Nine patients underwent multiple angiographies. In 11 patients (37.9%), IA revealed residual fistula after the surgeon determined that no lesion remained. This led to further exploration at the same sitting in 10 patients, while in 1 patient, further surgery was performed at a later date. False-negative findings on IA occurred in 3 patients (10.7%).IA is an important adjunct in surgery for DAVF. In this series, it resulted in further surgical treatment in 37.9% of patients. However, there was a 10% false-negative rate, which justified subsequent postoperative angiography.

    View details for DOI 10.3174/ajnr.A2443

    View details for Web of Science ID 000292066600024

    View details for PubMedID 21622580

  • Dural arteriovenous fistula following translabyrinthine resection of cerebellopontine angle tumors: report of two cases. Skull base reports Li, P. M., Fischbein, N. J., Do, H. M., Blevins, N. H. 2011; 1 (1): 51-58


    We describe two cases of dural arteriovenous fistula (DAVF) developing in a delayed fashion after translabyrinthine resection of cerebellopontine angle tumors. Two patients in an academic tertiary referral center, a 46-year-old woman and a 67-year-old man, underwent translabyrinthine resection of a 2-cm left vestibular schwannoma and a 4-cm left petrous meningioma, respectively. Both patients subsequently developed DAVF, and in each case the diagnosis was delayed despite serial imaging follow-up. In one patient, cerebrospinal fluid diversion before DAVF was identified as the cause of her intracranial hypertension; the other patient was essentially asymptomatic but with a high risk of hemorrhage due to progression of cortical venous drainage. Endovascular treatment was effective but required multiple sessions due to residual or recurrent fistulas. Dural arteriovenous fistula is a rare complication of translabyrinthine skull base surgery. Diagnosis requires a high index of clinical suspicion and an understanding of subtle imaging findings that may be present on follow-up studies performed for tumor surveillance. Failure to recognize this complication may lead to misguided interventions for treatment of hydrocephalus and other complications, as well as ongoing risks related to venous hypertension and intracranial hemorrhage. As this condition is generally curable with neurointerventional and/or surgical methods, timely diagnosis and treatment are essential.

    View details for DOI 10.1055/s-0031-1275634

    View details for PubMedID 23984203

    View details for PubMedCentralID PMC3743590

  • Predictors of Clinical and Angiographic Outcome After Surgical or Endovascular Therapy of Very Large and Giant Intracranial Aneurysms NEUROSURGERY Darsaut, T. E., Darsaut, N. M., Chang, S. D., Silverberg, G. D., Shuer, L. M., Tian, L., Dodd, R. L., Do, H. M., Marks, M. P., Steinberg, G. K. 2011; 68 (4): 903-915


    Risk factors for poor outcome in the treatment of very large (≥20-24 mm) and giant (≥25 mm) intracranial aneurysms remain incompletely defined.To present an aggregate clinical series detailing a 24-year experience with very large and giant aneurysms to identify and assess the relative importance of various patient, aneurysm, and treatment-specific characteristics associated with clinical and angiographic outcomes.The authors retrospectively identified 184 aneurysms measuring 20 mm or larger (85 very large, 99 giant) treated at Stanford University Medical Center between 1984 and 2008. Clinical data including age, presentation, and modified Rankin Scale (mRS) score were recorded, along with aneurysm size, location, and morphology. Type of treatment was noted and clinical outcome measured using the mRS score at final follow-up. Angiographic outcomes were completely occluded, occluded with residual neck, partly obliterated, or patent with modified flow.After multivariate analysis, risk factors for poor clinical outcome included a baseline mRS score of 2 or higher (odds ratio [OR], 0.23; 95% confidence interval [CI]: 0.08-0.66; P = .01), aneurysm size of 25 mm or larger (OR, 3.32; 95% CI: 1.51-7.28; P < .01), and posterior circulation location (OR, 0.18; 95% CI: 0.07-0.43; P < .01). Risk factors for incomplete angiographic obliteration included fusiform morphology (OR, 0.25; 95% CI: 0.10-0.66; P < .01), posterior circulation location (OR, 0.33; 95% CI: 0.13-0.83; P = .02), and endovascular treatment (OR, 0.14; 95% CI: 0.06-0.32; P < .01). Patients with incompletely occluded aneurysms experienced higher rates of posttreatment subarachnoid hemorrhage and had increased mortality compared with those with completely obliterated aneurysms.Our results suggest that patients with poor baseline functional status, giant aneurysms, and aneurysms in the posterior circulation had a significantly higher proportion of poor outcomes at final follow-up. Fusiform morphology, posterior circulation location, and endovascular treatment were risk factors for incompletely obliterated aneurysms.

    View details for DOI 10.1227/NEU.0b013e3182098ad0

    View details for PubMedID 21221025



    To integrate three-dimensional (3D) digital rotation angiography (DRA) and two-dimensional (2D) digital subtraction angiography (DSA) imaging into a targeting methodology enabling comprehensive image-guided robotic radiosurgery of arteriovenous malformations (AVMs).DRA geometric integrity was evaluated by imaging a phantom with embedded markers. Dedicated DSA acquisition modes with preset C-arm positions were configured. The geometric reproducibility of the presets was determined, and its impact on localization accuracy was evaluated. An imaging protocol composed of anterior-posterior and lateral DSA series in combination with a DRA run without couch displacement between acquisitions was introduced. Software was developed for registration of DSA and DRA (2D-3D) images to correct for: (a) small misalignments of the C-arm with respect to the estimated geometry of the set positions and (b) potential patient motion between image series. Within the software, correlated navigation of registered DRA and DSA images was incorporated to localize AVMs within a 3D image coordinate space. Subsequent treatment planning and delivery followed a standard image-guided robotic radiosurgery process.DRA spatial distortions were typically smaller than 0.3 mm throughout a 145-mm × 145-mm × 145-mm volume. With 2D-3D image registration, localization uncertainties resulting from the achievable reproducibility of the C-arm set positions could be reduced to about 0.2 mm. Overall system-related localization uncertainty within the DRA coordinate space was 0.4 mm. Image-guided frameless robotic radiosurgical treatments with this technique were initiated.The integration of DRA and DSA into the process of nidus localization increases the confidence with which radiosurgical ablation of AVMs can be performed when using only an image-guided technique. Such an approach can increase patient comfort, decrease time pressure on clinical and technical staff, and possibly reduce the number of cerebral angiograms needed for a particular patient.

    View details for DOI 10.1016/j.ijrobp.2010.05.015

    View details for PubMedID 20801584

  • CT Angiography as a Screening Tool for Dural Arteriovenous Fistula in Patients with Pulsatile Tinnitus: Feasibility and Test Characteristics AMERICAN JOURNAL OF NEURORADIOLOGY Narvid, J., Do, H. M., Blevins, N. H., Fischbein, N. J. 2011; 32 (3): 446-453


    The diagnosis of intracranial DAVF with noninvasive cross-sectional imaging such as CTA is challenging. We sought to determine the sensitivity and specificity of CTA compared with cerebral angiography for DAVF in patients presenting with PT.Following approval of the institutional review board, we reviewed all patients who underwent CTA for PT from 2004 to 2009 and collected clinical and imaging data. Seven patients with PT and proved DAVF and 7 age- and sex-matched control patients with PT but no DAVF composed the study group. CTA images were blindly interpreted by 2 experienced neuroradiologists for the presence of 5 variables: asymmetric arterial feeding vessels, "shaggy" appearance of a dural venous sinus, transcalvarial venous channels, asymmetric venous collaterals, and abnormal size and number of cortical veins. Asymmetric attenuation of jugular veins was additionally assessed.The presence of arterial feeders showed good test characteristics for screening, with a sensitivity of 86% (95% CI, 42-99) and a specificity of 100% (95% CI, 52-100). A shaggy sinus or tentorium was highly specific: sensitivity of 42% (95% CI, 11-79) and specificity of 100% (95% CI, 56-100). The presence of transcalvarial venous channels demonstrated a poor sensitivity of 29% (95% CI, 5-70) but a high specificity 86% (95% CI, 42-99). CT attenuation of the jugular veins showed statistically significant asymmetry in the DAVF group versus the control group (P < .05).CTA can be used to screen for DAVF in patients with PT. The presence of asymmetrically visible and enlarged arterial feeding vessels has a high sensitivity and specificity for the diagnosis of DAVF.

    View details for DOI 10.3174/ajnr.A2328

    View details for Web of Science ID 000288639800007

    View details for PubMedID 21402614

  • Enucleated eyes after failed intra-arterial infusion of chemotherapy for unilateral retinoblastoma: histopathologic evaluation of vitreous seeding. Clinical ophthalmology (Auckland, N.Z.) Kim, J., Do, H., Egbert, P. 2011; 5: 1655-1658


    Selective intra-arterial chemotherapy (IAC) has been adopted by many ocular oncology centers to treat advanced intraocular retinoblastoma. In this report, we describe two patients with unilateral intraocular retinoblastoma and persistent vitreous seeding, who were treated with IAC after failed systemic chemotherapy. Despite multiple sessions and increasing dosage of drug delivery, vitreous seeding in these cases failed to respond to IAC, and ultimately both eyes were enucleated for tumor control. Based on the histopathologic findings in these two cases, IAC appears to have limitations in treating persistent vitreous seeding in eyes which have failed systemic chemotherapy. Possible causes for failure of IAC to treat persistent vitreous seeding include poor vitreous penetration, inactive state of tumor seeds within the avascular vitreous cavity, and chemotherapeutic drug resistance.

    View details for DOI 10.2147/OPTH.S24318

    View details for PubMedID 22174572

    View details for PubMedCentralID PMC3236709

  • Frameless image guided robotic radiosurgery of arteriovenous malformation localized on spatially correlated digital subtraction and C-arm CT angiography images JOURNAL OF NEUROINTERVENTIONAL SURGERY Hristov, D., Adler, J. R., Gibbs, I. C., Dodd, R., Marks, M., Chang, S. D., Do, H. M. 2010; 2 (3): 252-254


    A case is reported of frameless image guided robotic radiosurgery for an arteriovenous malformation (AVM). C-arm CT (CACT) and concurrent digital subtraction angiography images were used for AVM localization within the CACT volume. Treatment planning was performed on CT images registered with the CACT dataset. During delivery, a robotic linear accelerator tracked the target based on localization with frequent stereoscopic x-ray imaging. This case demonstrates that a frameless approach to AVM radiosurgery is possible.

    View details for DOI 10.1136/jnis.2009.001941

    View details for PubMedID 21990637

  • Predictors of Clinical and Angiographic Outcome Following Surgical or Endovascular Therapy of Very Large and Giant Intracranial Aneurysms Darsaut, T. E., Darsaut, N. M., Chang, S. D., Silverberg, G. D., Shuer, L. M., Tian, L., Dodd, R. L., Do, H. M., Marks, M. P., Steinberg, G. K. LIPPINCOTT WILLIAMS & WILKINS. 2010: E266
  • Management of Pediatric Intracranial Arteriovenous Malformations: Experience With Multimodality Therapy Darsaut, T. E., Guzman, R., Marcellus, M. L., Edwards, M. S., Tian, L., Do, H. M., Chang, S. D., Levy, R. P., Adler, J. R., Marks, M. P., Steinberg, G. K. LIPPINCOTT WILLIAMS & WILKINS. 2010: E220
  • Intraoperative Neurophysiologic Monitoring in the Endovascular and Surgical Treatment of Pediatric Arteriovenous Malformations Nguyen, V., Cho, S., Chang, S., Steinberg, G., Alto, P., Marks, M., Do, H., Lopez, J. LIPPINCOTT WILLIAMS & WILKINS. 2010: A501
  • Facet Pain in Thoracic Compression Fractures PAIN MEDICINE Mitra, R., Do, H., Alamin, T., Cheng, I. 2010; 11 (11): 1674-1677


    To determine if thoracic facet joints may be a significant secondary pain generator in patients with compression fractures. Traditionally, pain from vertebral compression fractures has been attributed to vertebral body itself. Compression fractures have been shown to increase thoracic kyphosis and thereby increase the thoracic flexion moment; these changes eventually increase the shear stress on the posterior elements.We present a small case series of patients with thoracic compression fractures managed with intra-articular facet injections.Tertiary care academic medical center.Two patients with thoracic compression fractures.The subjects received fluoroscopically guided thoracic facet steroid injections for pain management.Change in verbal analog pain score.Patients with thoracic compression fractures received significant long-lasting relief after receiving fluoroscopically guided intra-articular injections.Facet joints may be abnormally stressed due to the increasing thoracic flexion moment in anterior compression fractures, which may serve as a secondary pain generator; intra-articular facet blocks may be an alternative to vertebroplasty.

    View details for Web of Science ID 000283989800011

    View details for PubMedID 21029349

  • Should CT Angiography Be Routinely Used in Patients Suspected of Having Aneurysmal Subarachnoid Hemorrhage? No! RADIOLOGY Jayaraman, M. V., Haas, R. A., Do, H. M., Meyers, P. M. 2010; 254 (1): 314-315

    View details for DOI 10.1148/radiol.09091614

    View details for Web of Science ID 000273820400040

    View details for PubMedID 20032163

  • Clinical outcome after 450 revascularization procedures for moyamoya disease JOURNAL OF NEUROSURGERY Guzman, R., Lee, M., Achrol, A., Bell-Stephens, T., Kelly, M., Do, H. M., Marks, M. P., Steinberg, G. K. 2009; 111 (5): 927-935


    Moyamoya disease (MMD) is a rare cerebrovascular disease mainly described in the Asian literature. To address a lack of data on clinical characteristics and long-term outcomes in the treatment of MMD in North America, the authors analyzed their experience at Stanford University Medical Center. They report on a consecutive series of patients treated for MMD and detail their demographics, clinical characteristics, and long-term surgical outcomes.Data obtained in consecutive series of 329 patients with MMD treated microsurgically by the senior author (G.K.S.) between 1991 and 2008 were analyzed. Demographic, clinical, and surgical data were prospectively gathered and neurological outcomes assessed in postoperative follow-up using the modified Rankin Scale. Association of demographic, clinical, and surgical data with postoperative outcome was assessed by chi-square, uni- and multivariate logistic regression, and Kaplan-Meier survival analyses.The authors treated a total of 233 adult patients undergoing 389 procedures (mean age 39.5 years) and 96 pediatric patients undergoing 168 procedures (mean age 10.1 years). Direct revascularization technique was used in 95.1% of adults and 76.2% of pediatric patients. In 264 patients undergoing 450 procedures (mean follow-up 4.9 years), the surgical morbidity rate was 3.5% and the mortality rate was 0.7% per treated hemisphere. The cumulative 5-year risk of perioperative or subsequent stroke or death was 5.5%. Of the 171 patients presenting with a transient ischemic attack, 91.8% were free of transient ischemic attacks at 1 year or later. Overall, there was a significant improvement in quality of life in the cohort as measured using the modified Rankin Scale (p < 0.0001).Revascularization surgery in patients with MMD carries a low risk, is effective at preventing future ischemic events, and improves quality of life. Patients in whom symptomatic MMD is diagnosed should be offered revascularization surgery.

    View details for DOI 10.3171/2009.4.JNS081649

    View details for PubMedID 19463046

  • Localization Technique for Frameless Image-guided Robotic Radiosurgery of Arteriovenous Malformations Hristov, D. H., Liu, L., Moore, T., Dodd, R., Marks, M., Gibbs, I. C., Adler, J., Chang, S., Do, H. ELSEVIER SCIENCE INC. 2009: S679–S680
  • Multimodality treatment of posterior fossa arteriovenous malformations JOURNAL OF NEUROSURGERY Kelly, M. E., Guzman, R., Sinclair, J., Bell-Stephens, T. E., Bower, R., Hamilton, S., Marks, M. P., Do, H. M., Chang, S. D., Adler, J. R., Levy, R. P., Steinberg, G. K. 2008; 108 (6): 1152-1161


    Posterior fossa arteriovenous malformations (AVMs) are relatively uncommon and often difficult to treat. The authors present their experience with multimodality treatment of 76 posterior fossa AVMs, with an emphasis on Spetzler-Martin Grades III-V AVMs.Seventy-six patients with posterior fossa AVMs treated with radiosurgery, surgery, and endovascular techniques were analyzed.Between 1982 and 2006, 36 patients with cerebellar AVMs, 33 with brainstem AVMs, and 7 with combined cerebellar-brainstem AVMs were treated. Natural history data were calculated for all 76 patients. The risk of hemorrhage from presentation until initial treatment was 8.4% per year, and it was 9.6% per year after treatment and before obliteration. Forty-eight patients had Grades III-V AVMs with a mean follow-up of 4.8 years (range 0.1-18.4 years, median 3.1 years). Fifty-two percent of patients with Grades III-V AVMs had complete obliteration at the last follow-up visit. Three (21.4%) of 14 patients were cured with a single radiosurgery treatment, and 4 (28.6%) of 14 with 1 or 2 radiosurgery treatments. Twenty-one (61.8%) of 34 patients were cured with multimodality treatment. The mean Glasgow Outcome Scale (GOS) score after treatment was 3.8. Multivariate analysis performed in the 48 patients with Grades III-V AVMs showed radiosurgery alone to be a negative predictor of cure (p = 0.0047). Radiosurgery treatment alone was not a positive predictor of excellent clinical outcome (GOS Score 5; p > 0.05). Nine (18.8%) of 48 patients had major neurological complications related to treatment.Single-treatment radiosurgery has a low cure rate for posterior fossa Spetzler-Martin Grades III-V AVMs. Multimodality therapy nearly tripled this cure rate, with an acceptable risk of complications and excellent or good clinical outcomes in 81% of patients. Radiosurgery alone should be used for intrinsic brainstem AVMs, and multimodality treatment should be considered for all other posterior fossa AVMs.

    View details for DOI 10.3171/JNS/2008/108/6/1152

    View details for PubMedID 18518720

  • Multimodality treatment of posterior fossa arteriovenous malformations - Response JOURNAL OF NEUROSURGERY Kelly, M. E., Guzman, R., Marks, M. P., Do, H. M., Chang, S. D., Adler, J. R., Steinberg, G. K. 2008; 108 (6): 1150-1151
  • Experimental study of intracranial hematoma detection with flat panel detector C-arm CT AMERICAN JOURNAL OF NEURORADIOLOGY Arakawa, H., Marks, M. P., Do, H. M., Bouley, D. M., Strobel, N., Moore, T., Fahrig, R. 2008; 29 (4): 766-772


    Intracranial hemorrhage is a commonly acknowledged complication of interventional neuroradiology procedures, and the ability to image hemorrhage at the time of the procedure would be very beneficial. A new C-arm system with 3D functionality extends the capability of C-arm imaging to include soft-tissue applications by facilitating the detection of low-contrast objects. We evaluated its ability to detect small intracranial hematomas in a swine model.Intracranial hematomas were created in 7 swine by autologous blood injection of various hematocrits (19%-37%) and volumes (1.5-5 mL). Four animals received intravascular contrast before obtaining autologous blood (group 1), and 3 did not (group 2). We scanned each animal by using the C-arm CT system, acquiring more than 500 images during a 20-second rotation through more than 200 degrees . Multiplanar reformatted images with isotropic resolution were reconstructed on the workstation by using product truncation, scatter, beam-hardening, and ring-artifact correction algorithms. The brains were harvested and sliced for hematoma measurement and compared with imaging findings.Five intracranial hematomas were created in group 1 animals, and all were visualized. Six were created in group 2, and 3 were visualized. One nonvisualized hematoma was not confirmed at necropsy. All the others in both groups were confirmed. In group 1 (with contrast), small hematomas were detectable even when the hematocrit was 19%-20%. In group 2 (without contrast) C-arm CT was able to detect small hematomas (<1.0 cm(2)) created with hematocrits of 29%-37%. The area of hematoma measured from the C-arm CT data was, on average, within 15% of the area measured from harvested brain.The image quality obtained with this implementation of C-arm CT was sufficient to detect experimentally created small intracranial hematomas. This capability should provide earlier detection of hemorrhagic complications that may occur during neurointerventional procedures.

    View details for DOI 10.3174/ajnr.A0898

    View details for Web of Science ID 000255129700029

    View details for PubMedID 18202240

  • Neurologic complications of arteriovenous malformation embolization using liquid embolic agents AMERICAN JOURNAL OF NEURORADIOLOGY Jayaraman, M. V., Marcellus, M. L., Hamilton, S., Do, H. M., Campbell, D., Chang, S. D., Steinberg, G. K., Marks, M. P. 2008; 29 (2): 242-246


    Embolization of arteriovenous malformations (AVMs) is commonly used to achieve nidal volume reduction before microsurgical resection or stereotactic radiosurgery. The purpose of this study was to examine the overall neurologic complication rate in patients undergoing AVM embolization and analyze the factors that may determine increased risk.We performed a retrospective review of all patients with brain AVMs embolized at 1 center from 1995 through 2005. Demographics, including age, sex, presenting symptoms, and clinical condition, were recorded. Angiographic factors including maximal nidal size, presence of deep venous drainage, and involvement of eloquent cortex were also recorded. For each embolization session, the agent used, number of pedicles embolized, the percentage of nidal obliteration, and any complications were recorded. Complications were classified as the following: none, non-neurologic (mild), transient neurologic deficit, and permanent nondisabling and permanent disabling deficits. The permanent complications were also classified as ischemic or hemorrhagic. Modified Rankin Scale (mRS) scores were collected pre- and postembolization on all patients. Univariate regression analysis of factors associated with the development of any neurologic complication was performed.Four hundred eighty-nine embolization procedures were performed in 192 patients. There were 6 Spetzler-Martin grade I (3.1%), 26 grade II (13.5%), 71 grade III (37.0%), 57 grade IV (29.7%), and 32 grade V (16.7%) AVMs. Permanent nondisabling complications occurred in 5 patients (2.6%) and permanent disabling complications or deaths occurred in 3 (1.6%). In addition, there were non-neurologic complications in 4 patients (2.1%) and transient neurologic deficits in 22 (11.5%). Five of the 8 permanent complications (2.6% overall) were ischemic, and 3 of 8 (1.6% overall) were hemorrhagic. Of the 178 patients who were mRS 0-2 pre-embolization, 4 (2.3%) were dependent or dead (mRS >2) at follow-up. Univariate analysis of risk factors for permanent neurologic deficits following embolization showed that basal ganglia location was weakly associated with a new postembolization neurologic deficit.Embolization of brain AVMs can be performed with a high degree of technical success and a low rate of permanent neurologic complications.

    View details for DOI 10.3174/ajnr.A0793

    View details for Web of Science ID 000253345200013

    View details for PubMedID 17974613

  • Endovascular embolization of the swine rete mirabile with Eudragit-E 100 polymer 73rd Annual Meeting of the American-Association-of-Neurological-Surgeons/Congress of Neurological Surgeons Cerebrovascular Section/American-Society-of-Interventional-and-Therapeutic-Neuroradiology Arakawa, H., Murayama, Y., DAVIS, C. R., Howard, D. L., Baumgardner, W. L., Marks, M. P., Do, H. M. AMER SOC NEURORADIOLOGY. 2007: 1191–96


    Both adhesive and nonabrasive embolic agents are available for arteriovenous malformation (AVM) embolization. The purpose of this study was to evaluate a novel ethanol-based nonadhesive liquid embolic material in a swine AVM model.Eudragit (copolymer of methyl and butyl methacrylate and dimethylaminoethyl methacrylate) was dissolved in 50% ethanol and 50% iopamidol. Eudragit was injected into 9 retia mirabilia (RMs). Ethanol and iopamidol mixture were injected into 4 RMs for comparison. Three RMs embolized with Eudragit mixture were evaluated both angiographically and histopathologically acutely (3-24 hours) and at 30 days and 90 days after embolization.No procedural complications from Eudragrit embolization were noted, including retention or adhesion of the microcatheter. Various degrees of inflammation were observed in the acute and 30-day specimens. Two RMs showed partial recanalization on both histopathology and follow-up angiography in the 30-day group. Arterial fibrosis and calcification were observed in the 30- and 90-day specimens. The internal elastic lamina was disrupted in the 30- and 90-day specimens, but there was no evidence of Eudragit extravasation or hemorrhage. Endothelial damage was seen in all specimens and was particularly severe in the 30- and 90-day specimens.Eudragit polymer induced inflammation in thrombosis similar to n-butyl 2-cyanoacrylate, but without the disadvantages of perivascular hemorrhage and extravasation of embolization material. Although recanalization of some embolized RMs was noted, further investigation into Eudragit as a potentially useful embolic material for brain AVMs is warranted.

    View details for DOI 10.3174/ajnr.A0536

    View details for Web of Science ID 000247395800044

    View details for PubMedID 17569986

  • Wherefore wingspan? AMERICAN JOURNAL OF NEURORADIOLOGY Kallmes, D. F., Do, H. M. 2007; 28 (6): 997-998

    View details for Web of Science ID 000247395800001

    View details for PubMedID 17569943

  • Surgical and endovascular management of symptomatic posterior circulation fusiform aneurysms JOURNAL OF NEUROSURGERY Coert, B. A., Chang, S. D., Do, H. M., Marks, M. P., Steinberg, G. K. 2007; 106 (5): 855-865


    Patients with fusiform aneurysms can present with subarachnoid hemorrhage (SAH), mass effect, ischemia, or unrelated symptoms. The absence of an aneurysm neck impedes the direct application of a clip and endovascular coil deployment. To evaluate the effects of their treatments, the authors retrospectively analyzed a consecutive series of patients with posterior circulation fusiform aneurysms treated at Stanford University Medical Center between 1991 and 2005.Forty-nine patients (mean age 53 years, male/female ratio 1.2:1) treated at the authors' medical center form the basis of the analysis. Twenty-nine patients presented with an SAH. The patients presenting without SAH had cranial nerve dysfunction (five patients), symptoms of mass effect (eight patients), ischemia (six patients), or unrelated symptoms (one patient). The aneurysms were located on the vertebral artery (VA) or posterior inferior cerebellar artery (PICA) (21 patients); vertebrobasilar junction (VBJ) or basilar artery (BA) (18 patients); and posterior cerebral artery (PCA) (10 patients). Pretreatment clinical grades were determined using the Hunt and Hess scale; for patients with unruptured aneurysms (Hunt and Hess Grade 0) functional subgrades were added. Outcome was evaluated using the Glasgow Outcome Scale (GOS) score during a mean follow-up period of 33 months. Overall long-term outcome was good (GOS Score 4 or 5) in 59%, poor (GOS Score 2 or 3) in 16%, and fatal (GOS Score 1) in 24% of the patients. In a univariate analysis, poor outcome was predicted by age greater than 55 years, VBJ location, pretreatment Hunt and Hess grade in patients presenting with SAH, and incomplete aneurysm thrombosis after endovascular treatment. In a multivariate analysis, age greater than 55 years was the confounding factor predicting poor outcome. Stratification by aneurysm location removed the effect of age. Of 13 patients with residual aneurysm after treatment, five (38%) subsequently died of SAH (three patients) or progressive mass effect/brainstem ischemia (two patients).Certain posterior circulation aneurysm locations (PCA, VA-PICA, and BA-VBJ) represent separate disease entities affecting patients at different ages with distinct patterns of presentation, treatment options, and outcomes. Favorable overall long-term outcome can be achieved in 90% of patients with PCA aneurysms, in 60% of those with VA-PICA aneurysms, and in 39% of those with BA-VBJ aneurysms when using endovascular and surgical techniques. The natural history of the disease was poor in patients with incomplete aneurysm thrombosis after treatment.

    View details for PubMedID 17542530

  • Dissection of the V4 segment of the vertebral artery: clinicoradiologic manifestations and endovascular treatment EUROPEAN RADIOLOGY Yoon, W., Seo, J. J., Kim, T. S., Do, H. M., Jayaraman, M. V., Marks, M. P. 2007; 17 (4): 983-993


    Intracranial vertebral artery (VA) dissection has three clinical presentations: ischemia, hemorrhage, and mass effect. Imaging findings of intracranial VA dissections vary according to clinical presentation. Irregular stenosis or occlusion of the VA is the most common finding in patients with posterior fossa infarction, whereas a dissecting aneurysm is the main feature in those with acute subarachnoid hemorrhage. A chronic, giant, dissecting aneurysm can cause mass effect on the brain stem or cranial nerves, as well as distal embolism. Magnetic resonance imaging is useful for detection of intramural hematomas and intimal flaps, both of which are diagnostic of VA dissection. Multidetector computed tomography angiography is increasingly used for diagnosis of VA dissection. Catheter angiography is still beneficial for evaluation of precise endoluminal morphology of the dissection before surgical or endovascular intervention. Endovascular treatment is now considered a major therapeutic option for patients with a ruptured dissecting aneurysm or a chronic dissecting aneurysm. Anticoagulation therapy is currently considered the initial treatment of choice in patients with posterior circulation ischemic symptoms. Endovascular treatment, such as stent-assisted angioplasty or coil occlusion at the dissection site, can be performed in selected patients with posterior fossa ischemic symptoms.

    View details for DOI 10.1007/s00330-006-0272-8

    View details for Web of Science ID 000244753900014

    View details for PubMedID 16670864

  • Morphologic assessment of middle cerebral artery aneurysms for endovascular treatment. Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association Jayaraman, M. V., Do, H. M., Versnick, E. J., Steinberg, G. K., Marks, M. P. 2007; 16 (2): 52-56


    Aneurysms of the middle cerebral artery (MCA) trifurcation region are underrepresented in large series of endovascularly treated aneurysms. The purpose of our study was to evaluate the incidence of specific morphologic features of MCA bifurcation aneurysms that may affect suitability for endovascular treatment.We evaluated 53 consecutive patients with 58 bifurcation or trifurcation MCA aneurysms seen for angiographic evaluation during a 4-year period at our institution. All angiograms were reviewed for: aneurysm size (largest dimension, dome and neck size), branch vessels originating from the aneurysm sac, straightening of the aneurysm wall to suggest intramural thrombus, calcification in the region of the aneurysm, stenosis of the parent vessel, and presence of daughter sacs.Of 58 aneurysms, 51 (88%) had a dome to neck ratio less than 2:1. Branch vessel incorporation in the aneurysm sac was seen in 23/58 (40%), straightening suggestive of thrombus in 14/58 (24%), calcification in 2/58 (3%), parent vessel stenosis in 1/58 (2%), and daughter sacs in 4/58 (7%).The majority of MCA aneurysms have morphologic features such as a dome to neck ratio less than 2:1 or branch vessel incorporation that may make them unsuitable for endovascular treatment using conventional intra-aneurysmal coiling.

    View details for PubMedID 17689394

  • Hemorrhage rate in patients with Spetzler-Martin grades IV and V arteriovenous malformations - Is treatment justified? STROKE Jayaraman, M. V., Marcellus, M. L., Do, H. M., Chang, S. D., Rosenberg, J. K., Steinberg, G. K., Marks, M. P. 2007; 38 (2): 325-329


    We sought to examine the prospective annual risk of hemorrhage in patients harboring Spetzler-Martin grades IV and V arteriovenous malformations (AVMs) before and after initiation of treatment.Medical records of 61 consecutive patients presenting with Spetzler-Martin grades IV and V AVMs were retrospectively reviewed for demographics, angiographic features, presenting symptom(s), and time of all hemorrhage events, before or after treatment initiation. Pretreatment hemorrhage rates (excluding hemorrhages at presentation) and posttreatment rates were subsequently calculated. Modified Rankin Scale (mRS) scores before and after treatment were recorded.The annual pretreatment hemorrhage rate for all patients was 10.4% per year (95% CI, 2.2 to 15.4%), 13.9% (95% CI, 3.5 to 22.1%) in patients with hemorrhagic presentation and 7.3% (2.6 to 14.3%) in patients with nonhemorrhagic presentation. Posttreatment hemorrhage rates were 6.1% per year (95% CI, 2.5 to 13.2%) for all patients, 5.6% (95% CI, 2.1 to 11.8%) for patients presenting with hemorrhage and 6.4% (95% CI, 1.6 to 10.1%) in patients with nonhemorrhagic presentation. A noninferiority test showed that the posttreatment hemorrhage rate was less than or equal to the pretreatment hemorrhage rate (P<0.0001), with some indication that the reduction was greatest in patients with hemorrhagic presentation. Of the 62 patients, 51 (82%) had an mRS score of 0 to 2 before treatment, and 47 (76%) had an mRS score of 0 to 2 at the last follow-up after treatment.The annual rate of hemorrhage in grades IV and V AVMs is higher in this series than reported for all AVMs, which may reflect some referral bias in this single-center study. Nevertheless, initiation of treatment does not appear to increase the rate of subsequent hemorrhage. Treatment for these lesions may be warranted, given their poor natural history.

    View details for DOI 10.1161/

    View details for PubMedID 17194881

  • Treatment of traumatic cervical arteriovenous fistulas with N-butyl-2-cyanoacrylate AMERICAN JOURNAL OF NEURORADIOLOGY Jayaraman, M. V., Do, H. M., Marks, M. P. 2007; 28 (2): 352-354


    We report 2 cases of traumatic arteriovenous fistulas in the neck treated with transarterial embolization with n-butyl-2-cyanoacrylate (n-BCA). In both cases, covered stent placement across the fistula to preserve the artery was not possible. Detachable coil placement was attempted in one case but was not successful. Both fistulas were successfully treated with n-BCA embolization. To our knowledge, these are the first 2 such cases reported of high-flow cervical arteriovenous fistulas treated with n-BCA embolization.

    View details for Web of Science ID 000244263200038

    View details for PubMedID 17297011

  • Comments on brain AVM embolization with Onyx AMERICAN JOURNAL OF NEURORADIOLOGY Do, H. M. 2007; 28 (1): 178
  • Carotid and vertebral rete mirabile in man presenting with intraparenchymal hemorrhage: a case report. Journal of stroke and cerebrovascular diseases : the official journal of National Stroke Association Li, G., Jayaraman, M. V., Lad, S. P., Adler, J., Do, H., Steinberg, G. K. 2006; 15 (5): 228-231


    Carotid and vertebral rete mirabile is an unusual segmental regression of both the cavernous carotid artery and transdural vertebral arteries with a network of collateral vessels seen rarely in human beings. We present a 57-year-old woman with carotid and vertebral rete mirabile who presented with an acute intraparenchymal hemorrhage. The majority of patients present with subarachnoid hemorrhage or ischemic stroke. This is the first case of a non-Asian patient presenting with an intraparenchymal hemorrhage. In this case report, we describe the clinical and angiographic features of this unusual entity.

    View details for PubMedID 17904080

  • Angioplasty for symptomatic intracranial stenosis - Clinical outcome STROKE Marks, M. P., Wojak, J. C., Al-Ali, F., Jayaraman, M., Marcellus, M. L., Connors, J. J., Do, H. M. 2006; 37 (4): 1016-1020


    Medical treatment of symptomatic intracranial stenosis carries a high risk of stroke. This study was done to evaluate the clinical and angiographic outcomes after intracranial angioplasty for this disease.A total of 120 patients with 124 intracranial stenoses were treated by primary angioplasty. All patients had neurologic symptoms (stroke or transient ischemic attack) attributable to intracranial stenoses > or =50%. Angiograms were evaluated before and after angioplasty for the degree of stenosis.Pretreatment stenoses varied from 50% to 95% (mean 82.2+/-10.2). Post-treatment stenoses varied from 0% to 90% (mean 36.0+/-20.1). There were 3 strokes and 4 deaths (all neurological) within 30 days of the procedure, giving a combined periprocedural stroke and death rate of 5.8%. A total of 116 patients (96.7%) were available for a mean follow-up time of 42.3 months. There were 6 patients who had a stroke in the territory of treatment and 5 additional patients with stroke in other territories. Ten deaths occurred during the follow-up period, none of which were neurological. Including the periprocedural stroke and deaths, this yielded an annual stroke rate of 3.2% in the territory of treatment and a 4.4% annual rate for all strokes.Intracranial angioplasty can be performed with a high degree of technical success and a low risk of complications. Long-term clinical follow-up of intracranial angioplasty patients demonstrates a risk of future strokes that compares favorably to patients receiving medical therapy.

    View details for DOI 10.1161/01.STR.0000206142.03677.c2

    View details for PubMedID 16497979

  • Progression of unilateral Moyamoya disease: A clinical series CEREBROVASCULAR DISEASES Kelly, M. E., Bell-Stephens, T. E., Marks, M. P., Do, H. M., Steinberg, G. K. 2006; 22 (2-3): 109-115


    The natural history of unilateral moyamoya disease (MMD) in adult patients is not clearly described in the literature. We present a series of 18 patients with unilateral MMD and analyze the risk factors for progression to bilateral disease.A retrospective review of 157 MMD patients treated at Stanford University Medical Center from 1991 to 2005 identified 28 patients with unilateral MMD (defined as none, equivocal or mild involvement on the contralateral side).Eighteen patients (5 males and 13 females) were identified with unilateral MMD and angiographic follow-up of > or =5 months. Mean radiologic follow-up (+/- standard error of the mean) was 19.3 +/- 3.4 months and mean clinical follow-up was 24.5 +/- 3.7 months. Five patients had childhood onset MMD and 13 patients had adult onset disease. Angiographic progression from unilateral to bilateral disease was seen in 7 patients (38.9%) at a mean follow-up of 12.7 +/- 2.4 months. Four of the 7 patients had significant clinical and radiologic progression requiring surgical intervention. Five of 7 patients that progressed had adult onset MMD. The presence of equivocal or mild stenotic changes of the contralateral anterior cerebral artery (ACA), middle cerebral artery (MCA) or internal carotid artery (ICA) was an important predictor of progression (p < 0.01); 6 of 8 patients (75%) with equivocal or mild contralateral disease progressed, whereas only 1 of 10 patients (10.0%) with no initial contralateral disease progressed to bilateral MMD. One patient had mild or equivocal MCA, ICA and ACA stenosis at the time of initial diagnosis and this patient progressed.Contralateral progression in the adult form occurs more commonly than previously reported. The presence of minor changes in the contralateral ACA, intracranial ICA and MCA is an important predictor of increased risk of progression. Patients with a completely normal angiogram on the contralateral side have a very low risk of progression.

    View details for DOI 10.1159/000093238

    View details for PubMedID 16685122

  • Mechanical thrombectomy following intravenous thrombolysis in the treatment of acute stroke ARCHIVES OF NEUROLOGY Lansberg, M. G., Fields, J. D., Albers, G. W., Jayaraman, M. V., Do, H. M., Marks, M. P. 2005; 62 (11): 1763-1765


    The efficacy of intravenous thrombolytics in acute stroke is limited by low rates of recanalization of occluded arteries. Treatment with intravenous thrombolytics followed by mechanical thrombectomy is a novel approach that may increase recanalization rates without compromising time to initiation of treatment.To report our experience with 2 patients who received this combination therapy and outline plans for a prospective pilot study.Case studies at a university hospital.Patients treated with intravenous thrombolytics within 3 hours of symptom onset subsequently underwent computed tomographic angiography. If an occlusion of a proximal cerebral vessel was shown by a computed tomographic angiogram, mechanical thrombectomy was performed. Patients were observed for 1 month after treatment.National Institutes of Health Stroke Scale (NIHSS) score.The computed tomographic angiography of 2 patients showed complete occlusion of the M1 branch of the middle cerebral artery following administration of intravenous thrombolytics. The NIHSS scores were 21 and 13. In both cases, blood flow through the occluded artery was restored with mechanical thrombectomy and dramatic neurologic improvement occurred. There were no complications. The NIHSS scores were 0 and 2 at 1-month follow-up.Treatment with intravenous thrombolytics followed by mechanical thrombectomy may improve outcomes in acute stroke patients and a pilot safety trial is warranted.

    View details for PubMedID 16286552

  • Visual field preservation after curative multi-modality treatment of occipital lobe artemovenous malformations NEUROSURGERY Sinclair, J., Marks, M. P., Levy, R. P., Adler, J. R., Chang, S. D., Lopez, J. R., Do, H. M., Bell-Stephens, T. E., Lim, M., Steinberg, G. K. 2005; 57 (4): 655-666


    Occipital lobe arteriovenous malformations (AVMs) provide challenging management decisions because of their proximity to the visual cortex and optic radiations. Preservation of visual function throughout treatment is the mainstay of therapeutic planning. We reviewed visual field (VF) outcomes of all patients who received curative treatment for occipital AVMs at Stanford University to evaluate the efficacy of different treatment strategies.We conducted a retrospective review of 55 patients with occipital AVMs treated at Stanford University between 1984 and 2003. Clinical presentation, AVM morphology, and treatment modality were correlated with VF function before and after therapeutic intervention.Of 55 patients, 48 (87.3%) underwent multimodality AVM treatment (7 patients < 3 yr from radiosurgery were excluded from final analysis). One patient died from intracerebral hemorrhage 11 months post-radiosurgery, and five patients deferred further treatment. Forty-two patients (87.5%) were cured, with no residual AVM on final angiography. Curative therapeutic modalities used included embolization alone (2 patients), microsurgery alone (6 patients), microsurgery with radiosurgery (1 patient), microsurgery with embolization (23 patients), radiosurgery with embolization (4 patients), and embolization with radiosurgery and microsurgery (6 patients). Mean follow-up was 5.8 years including treatment. VF follow-up was available in all 42 patients. Twenty-eight (66.7%) patients experienced no change in VFs, six (14.3%) patients with previously abnormal VFs improved, and eight (19.0%) patients showed worsening of VFs (although none developed a new homonymous VF deficit). Duration of treatment was related to VF outcome in patients who presented without a history of AVM-related hemorrhage.Occipital AVMs can be safely cured using multimodality strategies with minimal risk to visual function despite the proximity of these lesions to the visual cortex and associated pathways.

    View details for DOI 10.1227/01.NEU.0000175547.05291.85

    View details for PubMedID 16239877

  • Truly hybrid x-ray/MR imaging: Toward a streamlined clinical system 5th International Interventional MRI Symposium Ganguly, A., Wen, Z. F., Daniel, B. L., Butts, K., Kee, S. T., Rieke, V., Do, H. M., Pelc, N. J., Alley, M. T., Fahrig, R. ELSEVIER SCIENCE INC. 2005: 1167–77


    We have installed an improved X-ray/MR (XMR) truly hybrid system with higher imaging signal-to-noise ratio (SNR) and versatility than our first prototype. In our XMR design, a fixed anode X-ray fluoroscopy system is positioned between the two donut-shaped magnetic poles of a 0.5T GE Signa-SP magnet (SP-XMR). This paper describes the methods for increased compatibility between the upgraded x-ray and MR systems that have helped improve patient management.A GE OEC 9800 system (GE OEC Salt Lake City, UT) was specially reconfigured for permitting X-ray fluoroscopy inside the interventional magnet. A higher power X-ray tube, a new permanent tube mounting system, automatic exposure control (AEC), remote controlled collimators, choice of multiple frame rates, DICOM image compatibility, magnetically shimmed X-ray detector, X-ray compatible MR coil, and better RF shielding are the highlights of the new system. A total of 23 clinical procedures have been conducted with SP-XMR guidance of which five were performed using the new system.The 70% increased power for fluoroscopy, and a new 6 times higher power single frame imaging mode, has improved imaging capability. The choice of multiple imaging frame rates, AEC, and collimator control allow reduction in X-ray exposure to the patient. The DICOM formatting has permitted easy transfer of clinical images over the hospital PACS network. The increased MR compatibility of the detector and the X-ray transparent MR coil has enabled faster switching between X-ray and MR imaging modes.The improvements introduced in our SP-XMR system have further streamlined X-ray/MR hybrid imaging. Additional clinical procedures could benefit from the new SP-XMR imaging.

    View details for DOI 10.1016/j.acra.2005.03.076

    View details for PubMedID 16099685

  • Prospective analysis of clinical outcomes after percutaneous vertebroplasty for painful osteoporotic vertebral body fractures AMERICAN JOURNAL OF NEURORADIOLOGY Do, H. M., Kim, B. S., Marcellus, M. L., CURTIS, L., Marks, M. P. 2005; 26 (7): 1623-1628


    Previous studies have retrospectively reported the positive effects of percutaneous vertebroplasty. The purpose of our study was to evaluate prospectively the effects of vertebroplasty on mobility, analgesic use, pain, and SF-36 (short-form 36-item) scales for patients with painful vertebral compression fractures that are refractory to medical therapy.We prospectively followed 167 patients who received 207 vertebroplasty treatment sessions for stabilization of 264 symptomatic vertebral compression fractures between August 1999 and January 2003. The average age of patients was 74.6 years (SD = 12.2 years), and 76% were women. Pre- and postprocedural measurements of pain, mobility, analgesic use, and SF-36 scales were compared at 1 month after the procedure and between 6 months and 3 years after the procedure with the SF-36 scales.Respective pre- and post-treatment pain scores were 8.71 (SE = 0.1) and 2.77 (SE = 0.18; P < .00001). Respective pre- and post-treatment analgesic use scores were 2.93 (SE = 0.9) and 1.64 (SE = 0.09; P < .00001). Respective pre- and post-treatment activity levels were 2.66 (SE = 0.1) and 1.64 (SE = 0.11; P < .00001). There was a statistically significant improvement on nine of 10 SF-36 scales (P < .001) after 1 month and on eight of 10 SF-36 scales (P < .02) at long-term follow-up.Percutaneous vertebroplasty offers statistically significant benefits in decreasing pain, decreasing use of analgesics, and increasing mobility in appropriately selected patients. Percutaneous vertebroplasty also offers a statistically significant benefit in most SF-36 scales at both short- and long-term follow-up.

    View details for PubMedID 16091504

  • Mechanical thrombectomy for acute stroke AMERICAN JOURNAL OF NEURORADIOLOGY Versnick, E. J., Do, H. M., Albers, G. W., Tong, D. C., Marks, M. P. 2005; 26 (4): 875-879


    We evaluated a mechanical thrombectomy protocol to treat acute stroke and report the angiographic results and clinical outcomes.Patients with anterior circulation strokes <8 hours and posterior circulation strokes <12 hours were treated at a single center over 10 months. Patients were excluded if they were candidates for intravenous tissue plasminogen activator (tPA). Treatment involved one of two mechanical thrombectomy devices. Retrieval was augmented by low-dose intra-arterial tPA if needed. Outcome was measured by using the Modified Rankin score.Ten patients were treated: five with anterior circulation strokes, four with posterior circulation strokes, and one with embolic strokes involving both circulations. Mean National Institutes of Health Stroke Scale score at presentation was 24.6 +/- 10.9. In eight patients (80%), revascularization was successful (Thrombolysis in Acute Myocardial Infarction score, 3). Mean time from symptom onset to initiation of the procedure was 6 hours (5.3 hours for anterior circulation and 7.0 hours for posterior circulation). Mean time for recanalization from the start of the procedure was 1.17 +/- 0.58 hours for the six anterior circulation strokes and 2.75 +/- 1.34 hours in the two posterior circulation strokes. Five patients died within 48 hours; all had posterior circulation strokes. Mean Modified Rankin score at 90 days was 1.4.In this small series, mechanical thrombectomy of acute stroke appeared to improve recanalization rates compared with intra-arterial thrombolysis. No hemorrhagic complications occurred. Further study is required to determine the role of these techniques.

    View details for PubMedID 15814937

  • Intracranial Angioplasty without stenting for symptomatic atherosclerotic stenosis: Long-term follow-up AMERICAN JOURNAL OF NEURORADIOLOGY Marks, M. P., Marcellus, M. L., Do, H. M., Schraedley-Desmond, P. K., Steinberg, G. K., Tong, D. C., Albers, G. W. 2005; 26 (3): 525-530


    Angioplasty and stent placement have been reported for the treatment of intracranial stenosis. This study was undertaken to assess the efficacy and long-term clinical outcome of angioplasty without stent placement for patients with symptomatic intracranial stenosis.A retrospective study was done to evaluate 36 patients with 37 symptomatic atherosclerotic intracranial stenosis who underwent primary balloon angioplasty. All patients had symptoms despite medical therapy. Thirty-four patients were available for follow-up ranging from 6 to 128 months. Mean follow-up was 52.9 months.Mean pretreatment stenosis was 84.2% before angioplasty and 43.3% after angioplasty. The periprocedural death and stroke rate was 8.3% (two deaths and one minor stroke). Two patients had strokes in the territory of angioplasty at 2 and 37 months after angioplasty. The annual stroke rate in the territory appropriate to the site of angioplasty was 3.36%, and for those patients with a residual stenosis of > or =50% it was 4.5%. Patients with iatrogenic dissection (n=11) did not have transient ischemic attacks or strokes after treatment.Results of long-term follow-up suggest that intracranial angioplasty without stent placement reduces the risk of further stroke in symptomatic patients.

    View details for PubMedID 15760860

  • Alteration in the venous drainage of a dural arteriovenous fistula following angioplasty AMERICAN JOURNAL OF NEURORADIOLOGY Gutierrez, A., Do, H. M., Marks, M. P. 2004; 25 (6): 1086-1088


    The pattern of venous drainage from a dural arteriovenous fistula (DAVF) has been shown to affect the natural history of these lesions. Angioplasty and stent placement of the dural sinuses have been described to improve outflow in venous hypertensive states and may improve the venous drainage pattern from a DAVF. We report the case of a patient with a benign but stenosed type IIa transverse sinus DAVF who underwent angioplasty to improve venous outflow. This resulted in conversion of the DAVF to a more malignant type IIb drainage pattern with reflux into the cortical venous system.

    View details for PubMedID 15205154

  • N-butyl cyanoacrylate glue embolization of splenic artery aneurysms JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY Kim, B. S., Do, H. M., Razavi, M. 2004; 15 (1): 91-94


    A patient with Polyarteritis Nodosa presented with abdominal pain and low hematocrit level. Abdominal computed tomography (CT) depicted the presence of free blood and CT angiography revealed two aneurysms in the inferior branch of the splenic artery that were subsequently treated by endovascular transarterial embolization with N-Butyl Cyanoacrylate. Post embolization splenic arteriography demonstrated complete embolization of both aneurysms, including the inflow and outflow vessels.

    View details for DOI 10.1097/01.RVI.0000099537.29957.13

    View details for Web of Science ID 000228600100012

    View details for PubMedID 14709694

  • Neurophysiological monitoring in the endovascular therapy of aneurysms AMERICAN JOURNAL OF NEURORADIOLOGY Liu, A. Y., Lopez, J. R., Do, H. M., Steinberg, G. K., Cockroft, K., Marks, M. P. 2003; 24 (8): 1520-1527


    Endovascular aneurysm therapy has associated risks of ischemic complications. We undertook this study to evaluate the efficacy of neurophysiological monitoring (NPM) techniques in the detection of ischemic changes that may be seen during endovascular treatment of cerebral aneurysms.Thirty-five patients underwent NPM during endovascular treatment of cerebral aneurysms. The patients underwent a total of 50 endovascular procedures, including balloon test occlusion (19 patients), GDC embolization (22 patients), and permanent vessel occlusion (nine patients). NPM included electroencephalography, somatosensory evoked potentials, and/or brain stem auditory evoked potentials, depending on the location of the aneurysm.NPM changes were seen in nine (26%) of 35 patients and altered the management in five (14%) of 35 patients. In three of the five cases, NPM changes were observed without corresponding neurologic physical examination changes after balloon test occlusion (performed while the patients were under general anesthesia in two cases). In the two other cases in which NPM changes altered management, ischemia was detected at the time of intra-aneurysmal therapy while the patients were under general anesthesia. Overall, 18 of 35 patients underwent a total of 19 balloon test occlusion procedures. Of the 17 remaining patients, 13 underwent aneurysm coiling, two were not treated because of inability to safely place coils, and two were treated for distal aneurysms. Two patients developed transient neurologic deficits without concurrent NPM changes, representing false-negative NPM test results.NPM is a valuable adjunct to endovascular treatment of cerebral aneurysms. Our study suggests that these monitoring techniques may reduce ischemic complications and can be used to help guide therapeutic decisions.

    View details for PubMedID 13679263

  • Multimodality treatment of giant intracranial arteriovenous malformations NEUROSURGERY Chang, S. D., Marcellus, M. L., Marks, M. P., Levy, R. P., Do, H. M., Steinberg, G. K. 2003; 53 (1): 1-11


    Giant arteriovenous malformations (AVMs) (i.e., those greater than 6 cm at maximum diameter) are difficult to treat and often carry higher treatment morbidity and mortality rates than do smaller AVMs. In this study, we reviewed the treatment, angiographic results, and clinical outcomes in 53 patients with giant AVMs who were treated at Stanford between 1987 and 2001.The patients selected included 20 males (38%) and 33 females (62%). Their presenting symptoms were hemorrhage (n = 20; 38%), seizures (n = 18; 34%), headaches (n = 8; 15%), and progressive neurological deficits (n = 7; 13%). One patient was in Spetzler-Martin Grade III, 9 were in Spetzler-Martin Grade IV, and 43 were in Spetzler-Martin Grade V. The mean AVM size was 6.8 cm (range, 6-15 cm). AVM venous drainage was superficial (n = 7), deep (n = 20), or both (n = 26). At presentation, 31 patients (58%) were graded in excellent neurological condition, 17 were graded good (32%), and 5 were graded poor (9%).The patients were treated with surgery (n = 27; 51%), embolization (n = 52; 98%), and/or radiosurgery (n = 47; 89%). Most patients received multimodality treatment with embolization followed by surgery (n = 5), embolization followed by radiosurgery (n = 23), or embolization, radiosurgery, and surgery (n = 23). Nineteen patients (36%) were completely cured of their giant AVMs, 90% obliteration was achieved in 4 patients (8%), less than 90% obliteration was achieved in 29 patients (55%) who had residual AVMs even after multimodality therapy, and 1 patient was lost to follow-up. Of the 33 patients who either completed treatment or were alive more than 3 years after undergoing their most recent radiosurgery, 19 patients (58%) were cured of their AVMs. The long-term treatment-related morbidity rate was 15%. The clinical results after mean follow-up of 37 months were 27 excellent (51%), 15 good (28%), 3 poor (6%), and 8 dead (15%).The results in this series of patients with giant AVMs, which represents the largest series reported to date, suggest that selected symptomatic patients with giant AVMs can be treated successfully with good outcomes and acceptable risk. Multimodality treatment is usually necessary to achieve AVM obliteration.

    View details for PubMedID 12823868

  • Simplicity of randomized, controlled trials of percutaneous vertebroplasty. Pain physician Hirsch, J. A., Do, H. M., Kallmes, D., Ruedy, R. M., Jarvik, J. G. 2003; 6 (3): 342-343

    View details for PubMedID 16880881

  • Parent vessel occlusion for vertebrobasilar fusiform and dissecting aneurysms AMERICAN JOURNAL OF NEURORADIOLOGY Leibowitz, R., Do, H. M., Marcellus, M. L., Chang, S. D., Steinberg, G. K., Marks, M. P. 2003; 24 (5): 902-907


    Previous reports of outcome with permanent vessel occlusion (PVO) for large, giant, or fusiform aneurysms in the posterior circulation have been limited. We undertook this study to evaluate the perioperative (within 30 days) and follow-up outcomes for patients treated with permanent occlusion of the vertebral artery for vertebrobasilar fusiform and dissecting aneurysms.Thirteen consecutive patients were studied. Two groups were defined for the study. Group I patients underwent PVO to achieve complete thrombosis of the aneurysm. Group II patients underwent PVO to reduce flow to the aneurysm where complete thrombosis was not desirable. Modified Rankin scores were obtained at presentation and at follow-up (follow-up range, 1-76 months; mean, 22.0 months).All group I aneurysms were shown to be thrombosed on the angiograms obtained at the immediate follow-up examinations. Improvement in outcome scores was achieved by all group I patients. Improvement in Rankin scores after endovascular treatment was statistically significant (P =.026). All group II patients had complete occlusion of the vertebral artery; however, continued filling of the fusiform aneurysm was still observed. Four patients in group II died during the follow-up period. Two of these deaths were attributable to the aneurysms. Of the remaining three patients, two experienced clinical worsening and one remained stable.In this series, PVO for chronic fusiform and acute dissecting aneurysms of the vertebrobasilar system proved to be a useful therapeutic endovascular technique. Long-term outcomes suggest that patients with aneurysms involving only one vertebral artery, where complete thrombosis can be achieved, have better clinical outcomes than those who have aneurysms involving the basilar artery or both vertebral arteries, where complete thrombosis cannot achieved by using PVO.

    View details for Web of Science ID 000183021100024

    View details for PubMedID 12748092

  • Percutaneous vertebroplasty: rationale, clinical outcomes, and future directions NEUROIMAGING CLINICS OF NORTH AMERICA Do, H. M. 2003; 13 (2): 343-?


    Percutaneous transpediculate vertebroplasty is an innovative and successful treatment of painful osteoporotic and pathologic compression fractures that are refractory to medical therapy. Large-scale clinical series have shown that vertebroplasty can provide significant pain relief with very low complication rates. Expectations of positive results of the ongoing randomized trials are high. With the accumulation of scientific data, technological advancements, and acceptance by the general community, vertebroplasty may be become the standard of care for treatment of painful vertebral body compression fractures.

    View details for DOI 10.1016/S1052-5149(03)00029-7

    View details for Web of Science ID 000183789100017

    View details for PubMedID 13677812

  • Aneurysmal subarachnoid hemorrhage in patient's with Hunt and Hess grade 4 or 5: Treatment using the Guglielmi detachable coil system AMERICAN JOURNAL OF NEURORADIOLOGY Weir, R. U., Marcellus, M. L., Do, H. M., Steinberg, G. K., Marks, M. P. 2003; 24 (4): 585-590


    Patients in poor clinical condition (Hunt and Hess grade 4 or 5) after subarachnoid hemorrhage (SAH) have historically fared poorly and many often were excluded from aggressive treatment. Early aggressive surgical treatment of SAH can produce good-quality survival for a higher percentage of patients than previously reported. We assessed the outcome of patients with Hunt and Hess grade 4 or 5 who were treated with Guglielmi detachable coil (GDC) embolization.We retrospectively evaluated the records of 27 consecutive grade 4 and 5 patients with 29 aneurysms treated within 72 hours of SAH by using GDCs. Percentage aneurysm occlusion after embolization, perioperative complications, and symptoms of vasospasm were evaluated. Outcome was assessed with the Glasgow Outcome Scale.Sixteen patients (59%) were grade 4, and 11 (41%) were grade 5. Eighteen (67%) had one aneurysm, six (22%) had two aneurysms, and three (11%) had three aneurysms. Twenty-nine aneurysms were treated. Fourteen (48%) were completely occluded, and four (14%) were nearly completely occluded (>/=95% occlusion) at embolization. Eleven aneurysms (38%) had partial coiling (<95% occlusion). In the 27 patients, one technical (4%) and one clinical (4%) complication occurred at embolization. No rehemorrhage occurred in any patients (follow-up, 6-44 months; mean, 23 months). Twenty-five (92%) had vasospasm, and seven required endovascular treatment because of worsening clinical status. Sixteen patients (59%) died within 30 days of SAH. Eight patients (30%) had a good clinical outcome at a mean follow-up of 23 months.Patients with Hunt and Hess grade 4 or 5 after SAH can undergo successful coil embolization of the aneurysms despite their poor medical condition and a high frequency of vasospasm at the time of treatment. Morbidity and mortality rates with this disease are still high. These findings compare favorably with those published in surgical series for aggressively treated patients with Hunt and Hess grade 4 or 5.

    View details for PubMedID 12695185

  • Line scan diffusion imaging of the spine AMERICAN JOURNAL OF NEURORADIOLOGY Bammer, R., Herneth, A. M., Maier, S. E., Butts, K., Prokesch, R. W., Do, H. M., Atlas, S. W., Moseley, M. E. 2003; 24 (1): 5-12


    Recent findings suggest that diffusion-weighted imaging might be an important adjunct to the diagnostic workup of disease processes in the spine, but physiological motion and the challenging magnetic environment make it difficult to perform reliable quantitative diffusion measurements. Multi-section line scan diffusion imaging of the spine was implemented and evaluated to provide quantitative diffusion measurements of vertebral bodies and intervertebral disks.Line scan diffusion imaging of 12 healthy study participants and three patients with benign vertebral compression fractures was performed to assess the potential of line scan diffusion imaging of the spinal column. In a subgroup of six participants, multiple b-value (5-3005 s/mm(2)) images were obtained to test for multi-exponential signal decay.All images were diagnostic and of high quality. Mean diffusion values were (230 +/- 83) x 10(-6) mm(2)/s in the vertebral bodies, (1645 +/- 213) x 10(-6) mm(2)/s in the nuclei pulposi, (837 +/- 318) x 10(-6) mm(2)/s in the annuli fibrosi and ranged from 1019 x 10(-6) mm(2)/s to 1972 x 10(-6) mm(2)/s in benign compression fractures. The mean relative intra-participant variation of mean diffusivity among different vertebral segments (T10-L5) was 2.97%, whereas the relative difference in mean diffusivity among participants was 7.41% (P <.0001). The estimated measurement precision was <2%. A bi-exponential diffusion attenuation was found only in vertebral bodies.Line scan diffusion imaging is a robust and reliable method for imaging the spinal column. It does not suffer as strongly from susceptibility artifacts as does echo-planar imaging and is less susceptible to patient motion than are other multi-shot techniques. The different contributions from the water and fat fractions need to be considered in diffusion-weighted imaging of the vertebral bodies.

    View details for Web of Science ID 000180962400004

    View details for PubMedID 12533319

  • Intraosseous venography during percutaneous vertebroplasty: Is it needed? AMERICAN JOURNAL OF NEURORADIOLOGY Do, H. M. 2002; 23 (4): 508-509

    View details for Web of Science ID 000175512200004

    View details for PubMedID 11950636

  • Multimodality treatment of giant intracranial arteriovenous malformations Chang, S. D., Levy, R. P., Marks, M. P., Do, H., Marcellus, M., Steinberg, G. K. LIPPINCOTT WILLIAMS & WILKINS. 2002: 343–44
  • Imaging of acute subarachnoid hemorrhage with a fluid-attenuated inversion recovery sequence in an animal model: Comparison with non-contrast-enhanced CT AMERICAN JOURNAL OF NEURORADIOLOGY Woodcock, R. J., Short, J., Do, H. M., Jensen, M. E., Kallmes, D. F. 2001; 22 (9): 1698-1703


    Fluid-attenuated inversion recovery (FLAIR) MR imaging sequences have been previously described in the evaluation of acute subarachnoid hemorrhage (SAH) in human subjects and have demonstrated good sensitivity. The purpose of this study was to evaluate a FLAIR sequence in an animal model of SAH and to compare the results with those obtained with non-contrast-enhanced CT.SAH was experimentally induced in 18 New Zealand rabbits by injecting autologous arterial blood into the subarachnoid space of the foramen magnum. Nine animals had high-volume (1-2 mL) injections, and nine animals had low-volume (0.2-0.5 mL) injections. Four control animals were injected with 0.5 mL of saline. The animals were imaged with a FLAIR sequence and standard CT 2-5 hours after injection. Gross pathologic evaluation of seven of the animals was performed. Four blinded readers independently evaluated the CT and FLAIR images for SAH and graded the probability of SAH on a scale of 1 to 5 (1 = no hemorrhage, 5 = definite hemorrhage).Overall, the sensitivity of FLAIR was 89%, and the sensitivity of CT was 39% (P <.01). In animals with a high volume of SAH, the sensitivity of FLAIR was 100%, and the sensitivity of CT was 56%. In animals with a low volume of SAH, the sensitivity of FLAIR was 78%, and the sensitivity of CT was 22%. The specificity of FLAIR in animals without SAH was 100%, and the specificity of CT was 100%. The average reader score for FLAIR was 3.8, and that for CT was 2.2 (P <.001). Reader scores for FLAIR were higher than those for CT in 94% (P <.01) of animals with SAH and in 25% of animals without SAH (P >.05). Seven animals underwent gross pathologic examination, and all had blood in the subarachnoid space around the brain stem.FLAIR was more sensitive than CT in the evaluation of acute SAH in this model, especially when a high volume of SAH was present. This study provides a model for further experimentation with MR imaging in the evaluation of SAH. These findings are consistent with those of current clinical literature, which show FLAIR to be an accurate MR sequence in the diagnosis of SAH.

    View details for Web of Science ID 000171752400016

    View details for PubMedID 11673164

  • Hyperperfusion syndrome with hemorrhage after angioplasty for middle cerebral artery stenosis AMERICAN JOURNAL OF NEURORADIOLOGY Liu, A. Y., Do, H. M., Albers, G. W., Lopez, J. R., Steinberg, G. K., Marks, M. P. 2001; 22 (8): 1597-1601


    Hyperperfusion syndrome is a well-documented complication of carotid endarterectomy, as well as internal carotid artery angioplasty and stent placement. We report a similar complication after distal intracranial (middle cerebral artery [MCA] M2 segment) angioplasty. To our knowledge, this is the first report of hyperperfusion syndrome after intracranial angioplasty of a distal MCA branch.

    View details for PubMedID 11559514

  • Transforming growth factor beta-coated platinum coils for endovascular treatment of aneurysms: An animal study NEUROSURGERY de Gast, A. N., Altes, T. A., Marx, W. F., Do, H. M., Helm, G. A., Kallmes, D. F. 2001; 49 (3): 690-694


    To test the hypothesis that coating platinum coils with transforming growth factor beta (TGFbeta) would improve the cellular proliferation within experimental aneurysms relative to uncoated coils.Elastase-induced saccular aneurysms were created in 12 New Zealand White rabbits. These aneurysms were embolized with platinum coils, either "control" (unmodified) coils or "test" (coated with TGFbeta) coils. Subjects were killed either 2 weeks (n = 3, control; n = 3, test) or 6 weeks (n = 3, control; n = 3, test) after embolization. Aneurysm tissue was embedded in plastic, sectioned, and stained with hematoxylin and eosin. The thickness of tissue covering the coils at the coil-lumen interface was measured by use of a digital microscope, and was compared between groups by use of the Student's t test (P < or = 0.05).Two-week implantation samples demonstrated mean thickness of tissue overlying TGFbeta-coated coils of 36+/-15 microm and mean thickness of overlying control coils of 3+/-5 microm, indicating significantly thicker tissue growth covering test versus control coils (P = 0.02). Six-week implantation samples demonstrated mean thickness of tissue overlying TGFbeta-coated coils of 86+/-74 microm versus mean thickness overlying control coils of 37+/-6 mu; this difference did not reach statistical significance (P = 0.30). Thickness of tissue covering TGFbeta-coated coils did not change significantly from 2 to 6 weeks (P = 0.31). Tissue thickness over control coils increased significantly between 2 and 6 weeks (P = 0.002).TGFbeta-coated platinum coils undergo earlier cellular coverage than standard platinum coils, but differences in coverage between coated and control coils are no longer present at later time points. These data suggest that improvements in intra-aneurysmal cellular proliferation resulting from coil modifications, although significant in the early postembolization phase, may dissipate over time.

    View details for Web of Science ID 000170513600036

    View details for PubMedID 11523681

  • Choroid plexus papilloma of the third ventricle: angiography, preoperative embolization, and histology NEURORADIOLOGY Do, H. M., Marx, W. F., Khanam, H., Jensen, M. E. 2001; 43 (6): 503-506


    We report a unique case of choroid plexus papilloma of the third ventricle in an 8-month-old girl in which preoperative embolization played a salient role in management. Initial surgery was aborted due to excessive bleeding. Cerebral angiography demonstrated enlarged posterior choroidal arteries feeding the tumor, and intense, persistent tumor staining. These vessels were effectively embolized to stasis with polyvinyl alcohol particles. The patient underwent a second craniotomy and complete resection of the tumor with minimal blood loss. Postsurgical histology showed postembolization iatrogenic intratumoral necrosis.

    View details for Web of Science ID 000169547700016

    View details for PubMedID 11465767

  • Endovascular treatment of experimental aneurysms by use of biologically modified embolic devices: Coil-mediated intraaneurysmal delivery of fibroblast tissue allografts AMERICAN JOURNAL OF NEURORADIOLOGY Marx, W. F., Cloft, H. J., Helm, G. A., Short, J. G., Do, H. M., Jensen, M. E., Kallmes, D. F. 2001; 22 (2): 323-333


    Our long-term goal is to improve intraaneurysmal fibrosis after aneurysm embolization, by implanting exogenous fibroblasts, using platinum coils. For the current project, we tested two hypotheses: 1) that exogenous, fluorescence-labeled rabbit fibroblast allografts remained viable and proliferated within rabbit carotid arteries, and 2) that these fibroblast allografts could be reliably implanted into experimental aneurysms by use of platinum coils.Part 1. New Zealand White rabbit synovial fibroblasts obtained from a commercial vender were labeled with a fluorescent membrane marker. The common carotid arteries of New Zealand White rabbits were surgically exposed, ligated proximally and distally, and entered with 22-g angiocatheters. Through the angiocatheter we injected either phosphate-buffered saline-containing fluorescence-labeled fibroblasts (treatment vessels) or saline only (control vessels). The wounds were closed, and the subjects were kept alive for various time points up to 2 weeks. After sacrifice, the carotid artery segments were resected, processed for frozen-section histologic examination, and evaluated using epifluorescent microscopy and hematoxylin and eosin staining. Cell viability and proliferation were determined by comparing the treatment versus control vessels. Part 2. A) Fluorescence-labeled cells were grown in culture on platinum coils, which were then exposed to systemic arterial flow in the rabbit thoracic aorta for various lengths of time up to 40 minutes. The coil segments were then examined using fluorescent microscopy and the presence and relative amount of cells remaining on the coil were documented. B) Experimental aneurysms in rabbits were embolized with control platinum coils (n = 9) and platinum coils bearing rabbit synovial fibroblasts that were grown onto the coils in culture prior to implantation (n = 9). Subjects were sacrificed 3, 7, and 14 days after coil implantation. Histologic samples were studied to assess the presence or absence of nucleated cells within and around coil winds in order to determine whether fibroblasts had been successfully implanted into aneurysms. Data were evaluated using the chi-square test for statistical significance.Part 1. Fluorescence-labeled cells were examined in the treatment carotid artery segments and results were recorded at all time intervals. The treatment vessel segments showed evidence of progressive cellular proliferation, leading to complete vessel fibrosis at 2 weeks. Conversely, control vessel segments were filled predominately with unorganized thrombus at each time interval. Part 2. A) Numerous labeled fibroblasts remained adherent to the coil despite prolonged exposure to systemic arterial flow. B) Fibroblasts were seen adjacent to or within the central lumen of coils in eight (88%) of nine aneurysms treated with cell-bearing coils. Nucleated cells were not present in any of the nine control coil subjects. This represented a statistically significant difference (P < .001).Fibroblast allografts remain viable and proliferate in the vascular space in rabbits. Furthermore, these same fibroblasts, after seeding onto platinum coils in culture, remain protected within the lumen of the coils and are retained within the coil lumen even after prolonged exposure to arterial blood flow. Coils can be used to deliver viable fibroblasts directly into experimental aneurysms successfully. These findings indicate that coil-mediated cell implantation is feasible and may be a potential method of increasing the biological activity of embolic coils.

    View details for Web of Science ID 000167049300021

    View details for PubMedID 11156778

  • Magnetic resonance imaging in the evaluation of patients for percutaneous vertebroplasty. Topics in magnetic resonance imaging Do, H. M. 2000; 11 (4): 235-244


    Osteoporosis and osteoporotic compression fractures of the vertebral bodies are major health problems facing women and older people of both sexes. In the last several years, percutaneous vertebroplasty has been developed as a treatment for pain caused by vertebral body compression fractures and primary or metastatic neoplasms. A large part of the success of this procedure depends on correct patient selection. As such, magnetic resonance imaging (MRI) plays a vital role in this process. In this review, the clinical evaluation of patients considered for vertebroplasty, the role of MRI in the pretreatment process, the postvertebroplasty appearance of the spine on MRI, and the future applications, such as real-time guidance with MR imaging, will be discussed.

    View details for PubMedID 11133065

  • Adjuvant use of epsilon-aminocaproic acid (Amicar) in the endovascular treatment of cranial arteriovenous fistulae 83rd Scientific Assembly and Annual Meeting of the Radiological-Society-of-North-America Kallmes, D. F., Marx, W. F., Jensen, M. E., Cloft, H. J., Do, H. M., Lanzino, G., West, K., Dion, J. E. SPRINGER. 2000: 302–8


    We report our experience with the use of the antifibrinolytic agent epsilon-aminocaproic acid (EACA), Amicar, as an adjuvant to endovascular treatment of cranial arteriovenous fistulae. We also review applications of antifibrinolytic agents to neurovascular disorders and discuss the mechanism of action, dosing strategy, contraindications, and possible complications associated with the use of EACA. We identified 13 patients with cranial arteriovenous fistulae (five direct carotid cavernous fistulae [CCF], seven dural arteriovenous fistulae [DAVF], and one vein of Galen malformation) who received EACA as an adjunct to endovascular treatment. In all cases embolic coils were the primary embolic agent. We reviewed the modes of initial endovascular therapy and angiographic findings immediately thereafter and the response to EACA. Two direct CCF and two DAVF were completely thrombosed on follow-up angiography, and two DAVF demonstrated diminished flow after EACA therapy. Seven fistulae did not respond to EACA. Four of eight tightly coiled fistulae thrombosed, while none of five loosely coiled fistulae thrombosed. None of four cases with a residual fistula separate from the coil mass underwent thrombosis with EACA, while four of nine cases without a separate fistula thrombosed. There was no morbidity related to EACA therapy. EACA may thus be useful as an adjunct to endovascular treatment of cranial arteriovenous fistulae. Loose or incomplete coil packing of the fistula predicts a poor response to EACA therapy.

    View details for Web of Science ID 000087064800013

    View details for PubMedID 10872177

  • 1999 ARRS Executive Council Award. Creation of saccular aneurysms in the rabbit: a model suitable for testing endovascular devices. American Roentgen Ray Society. AJR. American journal of roentgenology Altes, T. A., Cloft, H. J., Short, J. G., DeGast, A., Do, H. M., Helm, G. A., Kallmes, D. F. 2000; 174 (2): 349-354


    This study developed an animal model of intracranial aneurysms suitable for evaluating emerging endovascular devices for aneurysmal therapy. We characterized the short-, medium-, and long-term attributes of this endovascular technique for saccular aneurysmal creation in the rabbit.The right common carotid artery was surgically exposed in nine New Zealand white rabbits. Using endovascular techniques, we occluded the origin of the right common carotid artery with a pliable balloon. Elastase was incubated endoluminally in the proximal common carotid artery above the balloon. The common carotid artery was ligated distally. Animals were studied angiographically and sacrificed at 2 weeks (n = 3), 10 weeks (n = 3), and 24 weeks (n = 3) after aneurysm creation. Histology was obtained.Saccular aneurysms formed in eight of the nine rabbits. The aneurysm projected from the apex of an approximately 90 degree curve of the parent vessel, the brachiocephalic artery. Mean aneurysm diameter was 4.5 mm (SD, 1.2 mm), and mean height was 7.5 mm (SD, 1.6 mm). All samples showed thinned elastic lamina and no evidence of inflammation. In four of eight aneurysms, unorganized thrombus was present in the dome of the aneurysm.Arterial aneurysms with intact endothelium and deficient elastic lamina were reliably created in an area of high shear stress in New Zealand white rabbits. Three of these aneurysms remained patent for at least 6 months. We found a simple procedure that can be readily applied to the testing of new endovascular devices for a reliable creation of aneurysms in rabbits.

    View details for PubMedID 10658703

  • Creation of saccular aneurysms in the rabbit: A model suitable for testing endovascular devices AMERICAN JOURNAL OF ROENTGENOLOGY Altes, T. A., Cloft, H. J., Short, J. G., DeGast, A., Do, H. M., Helm, G. A., Kallmes, D. F. 2000; 174 (2): 349-354


    This study developed an animal model of intracranial aneurysms suitable for evaluating emerging endovascular devices for aneurysmal therapy. We characterized the short-, medium-, and long-term attributes of this endovascular technique for saccular aneurysmal creation in the rabbit.The right common carotid artery was surgically exposed in nine New Zealand white rabbits. Using endovascular techniques, we occluded the origin of the right common carotid artery with a pliable balloon. Elastase was incubated endoluminally in the proximal common carotid artery above the balloon. The common carotid artery was ligated distally. Animals were studied angiographically and sacrificed at 2 weeks (n = 3), 10 weeks (n = 3), and 24 weeks (n = 3) after aneurysm creation. Histology was obtained.Saccular aneurysms formed in eight of the nine rabbits. The aneurysm projected from the apex of an approximately 90 degree curve of the parent vessel, the brachiocephalic artery. Mean aneurysm diameter was 4.5 mm (SD, 1.2 mm), and mean height was 7.5 mm (SD, 1.6 mm). All samples showed thinned elastic lamina and no evidence of inflammation. In four of eight aneurysms, unorganized thrombus was present in the dome of the aneurysm.Arterial aneurysms with intact endothelium and deficient elastic lamina were reliably created in an area of high shear stress in New Zealand white rabbits. Three of these aneurysms remained patent for at least 6 months. We found a simple procedure that can be readily applied to the testing of new endovascular devices for a reliable creation of aneurysms in rabbits.

    View details for Web of Science ID 000084885000013

  • Cerebral atrophy in Cushing's disease SURGICAL NEUROLOGY Simmons, N. E., Lipper, M. H., Laws, E. R. 2000; 53 (1): 72-76


    Cushing's disease causes significant pathological changes throughout the body as a result of elevated cortisol levels. Very few systematic investigations have focused on the morphologic effects of hypercortisolism on the central nervous system. The validity of using premature cerebral atrophy as a diagnostic tool for Cushing's disease remains unknown.This study includes 63 patients with Cushing's disease who were evaluated and treated at the University of Virginia Medical Center. Radiologists randomly compared these individuals with age- and sex-matched controls in a blinded protocol, assessing the degree of cerebral atrophy on computed tomography and magnetic resonance scans.Patients with Cushing's disease showed significant premature atrophy when compared with controls. This trend continued after subdividing the groups based on age and duration of symptoms except in the following groups: age greater than 60, duration of symptoms less than 1 year, and symptoms lasting between 4-5 years.Excluding the three aforementioned groups, the hypercortisolemic state manifested in patients with Cushing's disease promotes the premature development of cerebral atrophy, which can be identified on routine radiologic imaging and may assist in the clinical diagnosis of the condition.

    View details for Web of Science ID 000085420000029

    View details for PubMedID 10697236

  • Histologic evaluation of platinum coil embolization in an aneurysm model in rabbits RADIOLOGY Kallmes, D. F., Helm, G. A., Hudson, S. B., Altes, T. A., Do, H. M., Mandell, J. W., Cloft, H. J. 1999; 213 (1): 217-222


    To characterize the histologic response to platinum coil embolization by using a rabbit aneurysm model.Saccular aneurysms were created in New Zealand White rabbits by using vessel ligation with intraluminal elastase incubation. Aneurysms were subsequently embolized by using platinum coils. Subjects were sacrificed at various intervals up to 12 weeks following coil embolization. The aneurysm cavities and adjacent vessels were embedded in methylmethacrylate, were sectioned, and were stained for histologic examination.Two weeks following coil implantation, aneurysms were filled predominantly with unorganized thrombus. Six weeks following coil implantation, histologic features included complete filling of the aneurysm lumen with either prominent laminated but unorganized thrombus or areas of unorganized thrombus interspersed among areas of cellular infiltration. At 12 weeks following coil implantation, aneurysms were filled with the loosely packed, disordered cells contained within the extracellular matrix. Fibrosis or smooth muscle cell infiltration was not present in any of the 6- or 12-week samples.Platinum coils placed into experimental saccular aneurysms in New Zealand White rabbits failed to elicit a fibrotic response. This model can be used for the testing of biologic modifications of platinum coils aimed at increasing intra-aneurysmal fibrosis.

    View details for Web of Science ID 000082771900037

    View details for PubMedID 10540665

  • Percutaneous vertebroplasty in vertebral osteonecrosis (Kummell's spondylitis). Neurosurgical focus Do, H. M., Jensen, M. E., Marx, W. F., Kallmes, D. F. 1999; 7 (1)


    The authors report the clinical symptoms and response to therapy of a series of patients who presented with subacute or chronic back pain due to vertebral osteonecrosis (Kummell's spondylitis) and who underwent percutaneous vertebroplasty. The authors performed a retrospective chart review of a series of 95 patients in whom 149 painful, nonneoplastic compression fractures were demonstrated and who were treated with percutaneous transpediculate polymethylmethacrylate (PMMA) vertebroplasty. In six of these patients there was evidence of vertebral osteonecrosis, as evidenced by the presence of an intravertebral vacuum cleft on radiography or by intravertebral fluid on magnetic resonance (MR) imaging. Clinical and radiological findings on presentation were noted. Technical aspects of the vertebroplasty technique were compiled. Response to therapy, defined as qualitative change in pain severity and change in level of activity, was noted immediately following the procedure and at various periods on follow-up reviews. One man and five women, who ranged in age from 72 to 90 years (mean 81 years), were treated. Each patient had one compression fracture. The fractures were at T-11 (one patient), L-1 (two patients), L-3 (two patients), and L-4 (one patient). The pain pattern was described as severe and localized to the affected vertebra, and sometimes radiated along either flank. Pain duration ranged from 2 to 12 weeks, and the pain was refractory to conservative therapy that consisted of bedrest, analgesics, and external bracing. At the time of treatment, all patients were bedridden because of severe back pain. In all patients either plain radiographic or computerized tomography evidence of intravertebral vacuum cleft or MR imaging evidence of vertebral fluid collection consistent with avascular necrosis of the vertebral body was demonstrated. Four patients underwent bilateral transpediculate vertebroplasty, and two patients underwent unilateral transpediculate vertebroplasty. The fracture cavities were specifically targeted for PMMA injection. Additional fortification of the osteoporotic vertebral body trabeculae was also performed when feasible. "Cavitygrams" or intraosseous venograms with gentle contrast injection were obtained prior to application of cement mixture. In all patients subjective improvement in pain and increased mobility were demonstrated posttreatment. The follow-up period ranged from 4 to 24 hours after treatment. Two patients made additional office visits at 1 and 3 months, respectively. Patients presenting with vertebral osteonecrosis (Kummell's spondylitis) often suffer from local paraspinous or referred pain. When performing vertebroplasty on these patients, confirmation of entry into the fracture cavities with contrast-enhanced "cavitygrams" should be performed prior to injection of PMMA cement. The response to vertebroplasty with regard to amelioration of pain and improved mobility is encouraging.

    View details for PubMedID 16918233

  • The fate of neuroradiologic abstracts presented at national meetings in 1993: Rate of subsequent publication in peer-reviewed, indexed journals AMERICAN JOURNAL OF NEURORADIOLOGY Marx, W. F., Cloft, H. J., Do, H. M., Kallmes, D. F. 1999; 20 (6): 1173-1177


    Abstract presentations are a valuable means of rapidly conveying new information; however, abstracts that fail to eventually become published are of little use to the general medical community. Our goals were to determine the publication rate of neuroradiologic papers originally presented at national meetings in 1993 and to assess publication rate as a function of neuroradiologic subspecialty and study design.Proceedings from the 1993 ASNR and RSNA meetings were reviewed. A MEDLINE search encompassing 1993-1997 was performed cross-referencing lead author and at least one text word based on the abstract title. All ASNR and RSNA neuroradiologic abstracts were included. Study type, subspecialty classification, and sample size were tabulated. Publication rate, based on study design and neuroradiologic subspecialty, was compared with overall publication rate. Median duration from meeting presentation to publication was calculated, and the journals of publication were noted.Thirty-seven percent of ASNR abstracts and 33% of RSNA neuroradiologic abstracts were published as articles in indexed medical journals. Publication rates among neuroradiologic subspecialty types were not significantly different. Prospective studies presented at the ASNR were published at a higher rate than were retrospective studies. There was no difference between the publication rate of experimental versus clinical studies. Neuroradiologic abstracts were published less frequently than were abstracts within other medical specialties. Median time between abstract presentation and publication was 15 months.Approximately one third of neuroradiologic abstracts presented at national meetings in 1993 were published in indexed journals. This rate is lower than that of abstracts from medical specialties other than radiology.

    View details for Web of Science ID 000081922100042

    View details for PubMedID 10445467

  • Experimental side-wall aneurysms: a natural history study NEURORADIOLOGY Kallmes, D. F., Altes, T. A., Vincent, D. A., Cloft, H. J., Do, H. M., Jensen, M. E. 1999; 41 (5): 338-341


    We studied the natural history of canine side-wall experimental aneurysms to determine the incidence of spontaneous aneurysm thrombosis, to serve as control data for future studies focusing on development of aneurysm occlusion devices. Bilateral common carotid artery vein patch aneurysms were surgically created in eight mongrel dogs (20-25 kg). Duplex Doppler sonography was performed at 14 days and angiography between 30 and 210 days following aneurysm creation. Sonography demonstrated patency of 13 (81%) of 16 aneurysms. Patent aneurysms ranged in size from 8 x 10 mm to 14 x 16 mm. Conventional angiography was performed in four dogs approximately 30 days following aneurysm creation; in these four, all of 7 initially patent on sonography remained fully patent. One dog underwent conventional angiography at approximately 60 days following aneurysm creation; both aneurysms in this case remained widely patent. Three dogs underwent conventional angiography at approximately 200 days following aneurysm creation; all 4 aneurysms initially patent on sonography remained fully patent. None of the three aneurysms found to be occluded on sonographs demonstrated spontaneous recanalization. The canine side-wall aneurysm model is a valid tool for testing some aneurysm-occlusion devices, because control aneurysms remain patent indefinitely.

    View details for Web of Science ID 000080530600006

    View details for PubMedID 10379590

  • Perfusion imaging of the human lung using Flow-Sensitive Alternating Inversion Recovery with an Extra Radiofrequency pulse (FAIRER) MAGNETIC RESONANCE IMAGING Mai, V. M., Hagspiel, K. D., Christopher, J. M., Do, H. M., Altes, T., Knight-Scott, J., Stith, A. L., Maier, T., Berr, S. S. 1999; 17 (3): 355-361


    Pulmonary perfusion is an important parameter in the evaluation of lung diseases such as pulmonary embolism. A noninvasive MR perfusion imaging technique of the lung is presented in which magnetically labeled blood water is used as an endogenous, freely diffusible tracer. The perfusion imaging technique is an arterial spin tagging method called Flow sensitive Alternating Inversion Recovery with an Extra Radiofrequency pulse (FAIRER). Seven healthy human volunteers were studied. High-resolution perfusion-weighted images with negligible artifacts were acquired within a single breathhold. Different patterns of signal enhancement were observed between the pulmonary vessels and parenchyma, which persists up to TI = 1400 ms. The T1s of blood and lung parenchyma were determined to be 1.46s and 1.35 s, respectively.

    View details for Web of Science ID 000079291000004

    View details for PubMedID 10195578

  • Spinal cord infarction complicating embolisation of vertebral metastasis - A result of masking of a spinal artery by a high-flow lesion INTERVENTIONAL NEURORADIOLOGY Cloft, H. J., Jensen, M. E., Do, H. M., Kallmes, D. F. 1999; 5 (1): 61-65


    Summary: A 70-year-old woman presented with severe back pain secondary to metastasis of renal cell carcinoma to the second lumbar vertebral body. She had no evidence of spinal cord compression clinically or on MR imaging. Tumour embolisation was performed for pain relief The embolisation was complicated by spinal cord infarction resulting from angiographic masking of a spinal artery by diversion of contrast material into the high-flow tumour.

    View details for Web of Science ID 000080629500011

    View details for PubMedID 20670493

  • Dural arteriovenous fistula of the cervical spine presenting with subarachnoid hemorrhage AMERICAN JOURNAL OF NEURORADIOLOGY Do, H. M., Jensen, M. E., Cloft, H. J., Kallmes, D. E., Dion, J. E. 1999; 20 (2): 348-350


    We describe a case of dural arteriovenous fistula (DAVF) presenting with subarachnoid hemorrhage (SAH). The diagnosis of DAVF was based on spinal angiography. A review of the literature revealed that five of 13 previously reported DAVFs of the cervical spine were accompanied by SAH. SAH has not been observed in DAVFs involving other segments of the spinal canal.

    View details for Web of Science ID 000078982400037

    View details for PubMedID 10094368

  • Posterior inferior cerebellar artery aneurysms associated with posterior fossa arteriovenous malformation - Report of five cases and literature review SURGICAL NEUROLOGY Kaptain, G. J., Lanzino, G., Do, H. M., Kassell, N. F. 1999; 51 (2): 146-152


    The association of posterior inferior cerebellar artery (PICA) aneurysms with posterior fossa arteriovenous malformation (AVM) is uncommon. Over the past 3 years, five patients with this condition were treated at this institution. A review of the clinical history of these and other reported cases has illuminated common threads in the presentation, treatment, and outcome of these lesions.The findings of 27 patients (5 from our institution and 22 from the medical literature) with PICA aneurysms associated with AVMs were reviewed.Eighty-four percent of individuals presented with sub-arachnoid hemorrhage (SAH); 89% of these episodes resulted from aneurysm rupture documented by either intraoperative inspection or autopsy. All aneurysms were located on a feeding artery to the AVM, and 81% originated from distal portions of PICA. The majority of patients presented with Hunt & Hess grade I SAH; all patients who presented with hemorrhage were treated surgically. Surgical strategy was directed both to secure the aneurysm and to resect the AVM during the course of a single procedure. Although four individuals either died on admission or in the perioperative period, overall outcome was excellent or good in 82% of patients.PICA aneurysms associated with AVMs most often involve the distal segments of the artery. Patients usually present with SAH secondary to aneurysmal rupture. Surgical clipping of the aneurysm and excision of the AVM is possible in a single procedure with minimal morbidity. Overall prognosis is favorable in 80% of the cases.

    View details for Web of Science ID 000078645900016

    View details for PubMedID 10029418

  • Complete duplication or extreme fenestration of the basilar artery AMERICAN JOURNAL OF NEURORADIOLOGY Goldstein, J. H., Woodcock, R., Do, H. M., Phillips, C. D., Dion, J. E. 1999; 20 (1): 149-150


    We describe a 42-year-old man with complete duplication or extreme fenestration of the basilar artery. We review the developmental anatomy and embryology and discuss the possible clinical implications and associated findings of this anomaly.

    View details for Web of Science ID 000078385300026

    View details for PubMedID 9974071

  • CT-guided percutaneous drainage of syringomyelia JOURNAL OF COMPUTER ASSISTED TOMOGRAPHY Goldstein, J. H., Kaptain, G. J., Do, H. M., Cloft, H. J., Jane, J. A., Phillips, C. D. 1998; 22 (6): 984-988


    Our purpose is to describe CT-guided percutaneous drainage of syringomyelia as a possible contribution in patient management.CT-guided percutaneous drainage was performed on three patients with symptomatic syringomyelia. We determined the success of percutaneous decompression by subsequent CT and MRI. The effect of syringomyelia decompression in relation to the patient's symptoms was determined. This information was then used to help guide clinical management.In Case 1, percutaneous drainage of a large syrinx in a C5 quadriplegic patient with increasing lower extremity spasticity demonstrated significant decompression by imaging but did not result in clinical improvement. A surgical procedure to decompress the syrinx was not performed on the basis of this information. In Case 2, percutaneous drainage of a large syrinx in a quadriplegic patient with increasing upper extremity numbness and weakness demonstrated significant decompression by imaging and resulted in sustained clinical improvement, temporarily obviating the need for surgery. In Case 3, percutaneous drainage of the rostral aspect of a septated syrinx cavity in a patient with a Chiari I malformation and a syringoperitoneal shunt in place resulted in decompression by imaging but failed to relieve the patient's newly developed symptoms. An additional shunt was therefore not placed. In no case did the patient experience periprocedural complications or worsening of symptoms.CT-guided percutaneous drainage of syringomyelia is a safe and successful technique. It can be used diagnostically to identify patients that may or may not benefit from surgical syrinx decompression and in some cases may provide a temporary therapeutic alternative to surgery.

    View details for Web of Science ID 000077124400026

    View details for PubMedID 9843244

  • Brown-Sequard syndrome of the cervical spinal cord after chiropractic manipulation AMERICAN JOURNAL OF NEURORADIOLOGY Lipper, M. H., Goldstein, J. H., Do, H. M. 1998; 19 (7): 1349-1352


    We report a case of increased signal in the left hemicord at the C4 level on T2-weighted MR images after chiropractic manipulation, consistent with contusion. The patient displayed clinical features of Brown-Séquard syndrome, which stabilized with immobilization and steroids. Follow-up imaging showed decreased cord swelling with persistent increased signal. After physical therapy, the patient regained strength on the left side, with residual decreased sensation to pain involving the right arm.

    View details for Web of Science ID 000075475900037

    View details for PubMedID 9726481

  • Patterns of hemorrhage with ruptured posterior inferior cerebellar artery aneurysms: CT findings in 44 cases AMERICAN JOURNAL OF ROENTGENOLOGY Kallmes, D. F., Lanzino, G., Dix, J. E., Dion, J. E., Do, H., Woodcock, R. J., Kassell, N. F. 1997; 169 (4): 1169-1171


    We intended to characterize the CT patterns of hemorrhage associated with ruptured posterior inferior cerebellar artery (PICA) aneurysms.CT scans of 44 cases of angiographically confirmed ruptured saccular PICA aneurysms (4) aneurysms at the junction of the vertebral artery and the PICA and three distal PICA aneurysms) were retrospectively reviewed. All scans had been obtained within 2 days of the subarachnoid hemorrhage (SAH) (day 0 [less than 24 hr], 35 patients; day 1, eight patients; day 2, one patient). Presence or absence of hemorrhage in specific subarachnoid, intraventricular, and intraparenchymal locations was noted, as were the presence and degree of hydrocephalus.Posterior fossa SAH was present in 95% of cases. Isolated posterior fossa SAH was present in 30% of cases, but in no case was isolated supratentorial SAH present. Supratentorial SAH was present in 70% of cases. SAH involving the sylvian fissure or the interhemispheric region was present in 25% and 23% of cases, respectively. SAH along the convexity was present in 2% of cases. Intraventricular hemorrhage (IVH) with or without associated SAH was seen in 95% of cases, whereas isolated IVH was seen in 5% of cases. Hydrocephalus was present in 95% of cases and was moderate to marked in 70%. Both IVH and hydrocephalus were present in 93% of cases.Ruptured PICA aneurysms almost always coexist with hydrocephalus and IVH, as seen in 93% of cases, and almost never coexist with SAH along the convexity. The most common pattern of hemorrhage associated with such aneurysms includes IVH and posterior fossa hemorrhage. Extensive supratentorial SAH, in conjunction with posterior fossa SAH, is a common finding in patients with ruptured PICA aneurysms. SAH isolated to the posterior fossa is present in a sizeable minority of cases.

    View details for Web of Science ID A1997XW98100047

    View details for PubMedID 9308484

  • Complications of peritoneal dialysis: Evaluation with CT peritoneography 81st Scientific Assembly and Annual Meeting of the Radiological-Society-of-North-America (RSNA 95) Cochran, S. T., Do, H. M., Ronaghi, A., Nissenson, A. R., Kadell, B. M. RADIOLOGICAL SOC NORTH AMER. 1997: 869–78


    Computed tomographic (CT) peritoneography involves CT of the abdomen and pelvis after administration of a mixture of contrast material and dialysate. CT peritoneography can demonstrate a variety of complications of continuous ambulatory peritoneal dialysis. In patients with symptoms of peritonitis, CT peritoneography is better than conventional CT in demonstrating loculated fluid collections and indicates adhesions by means of uneven distribution of the contrast material-dialysate mixture. In patients with edema or abdominal bulging, CT peritoneography reliably shows the site of dialysate leakage and allows differentiation of a leak from a hernia. In patients with problems of fluid return, catheter malposition and its effect on dialysate distribution can be determined with CT peritoneography. In patients with poor ultrafiltration, demonstration of restricted space in the pelvis or poor distribution of fluid with CT peritoneography suggests adhesions. CT peritoneography also provides anatomic information for referring physicians that may determine whether treatment is medical or surgical.

    View details for Web of Science ID A1997XH28200007

    View details for PubMedID 9225388

  • Ion implantation and protein coating of detachable coils for endovascular treatment of cerebral aneurysms: Concepts and preliminary results in swine models NEUROSURGERY Murayama, Y., Vinuela, F., Suzuki, Y., Do, H. M., Massoud, T. F., Guglielmi, G., Ji, C., Iwaki, M., Kusakabe, M., Kamio, M., Abe, T. 1997; 40 (6): 1233-1243


    Complete anatomic obliteration remains difficult to achieve with endovascular treatment of wide-necked aneurysms using Guglielmi detachable platinum coils (GDCs). Ion implantation is a physicochemical surface modification process resulting from the impingement of a high-energy ion beam. Ion implantation and protein coating were used to alter the surface properties (thrombogenicity, endothelial cellular migration, and adhesion) of GDCs. These modified coils were compared with standard GDCs in the treatment of experimental swine aneurysms.In an initial study, straight platinum coils were used to compare the acute thrombogenicity of standard and modified coils. Modified coils were coated with albumin, fibronectin, or collagen and underwent Ne+ ion implantation at a dose of 1 x 10(15) ions/cm2 and an energy of 150 keV. Coils were placed in common iliac arteries of 17 swine for 1 hour, to evaluate their acute interactions with circulating blood. In a second study, GDCs were used to treat 34 aneurysms in an additional 17 swine. GDCs were coated with fibronectin, albumin, collagen, laminin, fibrinogen, or vitronectin and then implanted with ions as described above. Bilateral experimental swine aneurysms were embolized with standard GDCs on one side and with ion-implanted, protein-coated GDCs on the other side. The necks of aneurysms were evaluated macroscopically at autopsy, by using post-treatment Day 14 specimens. The dimensions of the orifice and the white fibrous membrane that covered the orifice were measured as the fibrous membrane to orifice proportion. Histopathological evaluation of the neck region was performed by light microscopy and scanning electron microscopy.Fibronectin-coated, ion-implanted coils showed the greatest acute thrombogenicity (average thrombus weight for standard coils, 1.9 +/- 1.5 mg; weight for fibronectin-coated coils, 8.6 +/- 6.2 mg; P < 0.0001). By using scanning electron microscopy, an intensive blood cellular response was observed on ion-implanted coil surfaces, whereas this was rare with standard coils. At Day 14, greater fibrous coverage of the necks of aneurysms was observed in the ion-implanted coil group (mean fibrous membrane to orifice proportion of 69.8 +/- 6.2% for the ion-implanted coil group, compared with 46.8 +/- 15.9% for the standard coil group; P = 0.0143).The results of this preliminary experimental study indicate that ion implantation combined with protein coating of GDCs improved cellular adhesion and proliferation. Future application of this technology may provide early wound healing at the necks of embolized, wide-necked, cerebral aneurysms.

    View details for Web of Science ID A1997XC45000058

    View details for PubMedID 9179897

  • ANTERIOR CRUCIATE LIGAMENT TEAR - INDIRECT SIGNS AT MR-IMAGING RADIOLOGY Gentili, A., Seeger, L. L., Yao, L., Do, H. M. 1994; 193 (3): 835-840


    To establish the sensitivity and specificity of indirect signs at magnetic resonance (MR) imaging of anterior cruciate ligament (ACL) tear.MR images of the knees of 89 consecutive patients (54 with torn and 35 with normal ACLs) were reviewed.The indirect signs were as follows (first percentage is sensitivity; the second, specificity): angle between lateral tibial plateau and ACL less than 45 degrees (90%, 97%); angle between Blumenstaat line and ACL more than 15 degrees (89%, 100%); bone contusions in lateral compartment (54%, 100%); position of posterior cruciate ligament (PCL) line (52%, 91%); PCL angle less than 107 degrees (52%, 94%); PCL bowing ratio more than 0.39 (34%, 100%); posterior displacement of lateral meniscus more than 3.5 mm (44%, 94%); anterior displacement of tibia more than 7 mm (41%, 91%); and lateral femoral sulcus deeper than 1.5 mm (19%, 100%).Because the specificity is high, the presence of indirect signs corroborates the diagnosis of ACL tear. Because the sensitivity is low, the absence of these signs does not exclude the diagnosis of ACL tear.

    View details for Web of Science ID A1994PT55300049

    View details for PubMedID 7972834



    The plantar plate of the foot is formed by the plantar aponeurosis and plantar capsule. The plantar plate arises from the distal plantar aspect of the metatarsal neck and inserts on the plantar aspect of the proximal phalangeal base. This thick plate supports the undersurface of the metatarsal head and resists hyperextension of the metatarsophalangeal joint (MTPJ) [1]. Plantar plate rupture may present as lesser metatarsalgia (the lesser metatarsals are the second through fifth), occasionally with exuberant synovitis. Plantar plate derangement also plays a central role in the genesis of the common hammertoe [2, 3]. Rupture or degeneration of the plantar plate destabilizes the MTPJ, allowing dorsal subluxation of the proximal phalanx. The resulting "cock-up" deformity at the MTPJ shortens and compromises the action of the extensor digitorum longus tendon, contributing over time to a flexion deformity at the interphalangeal joints.

    View details for Web of Science ID A1994PF50400030

    View details for PubMedID 8079860


    View details for Web of Science ID A1992KY02500008

    View details for PubMedID 1491435



    This essay illustrates the appearance of the traumatized spleen on CT scans obtained during the course of conservative treatment. Although the CT appearance of acute rupture of the spleen has been adequately described, little has been reported about the appearance of the spleen as it heals after trauma. Examples of CT studies of splenic injuries illustrate the various changes in appearance over time in the traumatized spleen that is treated nonoperatively.

    View details for Web of Science ID A1991GF74300016

    View details for PubMedID 1892031