- Interventional Radiology
- Diagnostic Radiology
Board Certification: Diagnostic Radiology, American Board of Radiology (2012)
Fellow, Cincinnati Children's Medical Center, Pediatric Radiology and Interventional Radiology
Fellow, Duke University Medical Center, Interventional Radiology
Resident, Duke University Medical Center, Radiology
MD, University of Michigan Medical School
MPH, University of North Carolina Gillings School of Global Public Health
Study of SRP-4045 and SRP-4053 in DMD Patients
The main objective of this study is to evaluate the efficacy of SRP-4045 and SRP-4053 compared to placebo in Duchenne muscular dystrophy (DMD) patients with out-of-frame deletion mutations amenable to skipping exon 45 and exon 53, respectively.
Postdoctoral Research Mentor
Stereotactic body radiotherapy for pediatric hepatocellular carcinoma with central biliary obstruction
PEDIATRIC BLOOD & CANCER
2017; 64 (6)
Here, we present the case of a pediatric patient with newly diagnosed hepatocellular carcinoma causing central biliary obstruction and persistently elevated bilirubin of 3.0-4.3 mg/dl despite placement of bilateral internal-external biliary drains. The tumor was not resectable, and the patient was not a candidate for liver transplant due to nodal disease, for chemotherapy due to hyperbilirubinemia, or for local therapies aside from stereotactic body radiotherapy (SBRT). In this report, we discuss the successful use of SBRT in the management of this patient, and its role in allowing the patient to become a candidate for additional therapies.
View details for DOI 10.1002/pbc.26330
View details for Web of Science ID 000400616500005
View details for PubMedID 28436210
- The Image Gently Think A-Head Campaign: Keep Calm and Image Gently. Journal of the American College of Radiology 2017; 14 (2): 301-302
Performance of a Machine Learning Classifier of Knee MRI Reports in Two Large Academic Radiology Practices: A Tool to Estimate Diagnostic Yield.
AJR. American journal of roentgenology
The purpose of this study is to evaluate the performance of a natural language processing (NLP) system in classifying a database of free-text knee MRI reports at two separate academic radiology practices.An NLP system that uses terms and patterns in manually classified narrative knee MRI reports was constructed. The NLP system was trained and tested on expert-classified knee MRI reports from two major health care organizations. Radiology reports were modeled in the training set as vectors, and a support vector machine framework was used to train the classifier. A separate test set from each organization was used to evaluate the performance of the system. We evaluated the performance of the system both within and across organizations. Standard evaluation metrics, such as accuracy, precision, recall, and F1 score (i.e., the weighted average of the precision and recall), and their respective 95% CIs were used to measure the efficacy of our classification system.The accuracy for radiology reports that belonged to the model's clinically significant concept classes after training data from the same institution was good, yielding an F1 score greater than 90% (95% CI, 84.6-97.3%). Performance of the classifier on cross-institutional application without institution-specific training data yielded F1 scores of 77.6% (95% CI, 69.5-85.7%) and 90.2% (95% CI, 84.5-95.9%) at the two organizations studied.The results show excellent accuracy by the NLP machine learning classifier in classifying free-text knee MRI reports, supporting the institution-independent reproducibility of knee MRI report classification. Furthermore, the machine learning classifier performed well on free-text knee MRI reports from another institution. These data support the feasibility of multiinstitutional classification of radiologic imaging text reports with a single machine learning classifier without requiring institution-specific training data.
View details for DOI 10.2214/AJR.16.16128
View details for PubMedID 28140627
- Endovascular Management of May-Thurner Syndrome in Adolescents: A Single-Center Experience JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY 2017; 28 (1): 71-77
Endovascular Management of May-Thurner Syndrome in Adolescents: A Single-Center Experience.
Journal of vascular and interventional radiology
To report a single-center experience in regard to the technique, safety, and clinical outcomes of endovascular therapy for treatment of May-Thurner syndrome (MTS) in adolescent patients.A retrospective review identified 10 patients (6 female; mean age, 16 y; range, 12-18 y; mean weight, 73 kg; range, 50-116 kg) treated by endovascular therapy for MTS from 1998 to 2015. Clinical presentations consisted of acute thrombotic MTS (n = 6) and nonthrombotic MTS (n = 4). Catheter-directed thrombolysis was performed in all cases of thrombosis. Venoplasty and stent placement were performed in all cases. Self-expanding stents 12-16 mm in diameter and 4-9 cm in length were deployed.No major periprocedural complications were observed. Median follow-up was 32 months (range, 6-109 mo). Primary and secondary patency rates were 79% and 100% at 12 months and 79% and 89% at 36 months, respectively. In a single patient with permanent loss of flow in the treated segment, multiple risk factors for thrombosis were identified. Rates of posttreatment symptoms were 0% by Villalta score and 60% (n = 6; mild symptoms) by modified Villalta score at the last clinical follow-up.Endovascular therapy for the treatment of MTS in our adolescent cohort was safe and effective in relieving venous obstruction. Stent placement in patients with underlying thrombophilic disorders is associated with loss of secondary patency, suggesting the need for further consideration in this population.
View details for DOI 10.1016/j.jvir.2016.09.005
View details for PubMedID 27818112
Ultrasound Guided Liver Biopsy with Gelatin Sponge Pledget Tract Embolization in Infants Weighing Less Than 10 kg.
Journal of pediatric gastroenterology and nutrition
The aim of the study was to describe and assess the technical success and safety of ultrasound-guided liver biopsy with gelatin sponge pledget tract embolization technique in infants <10 kg across 3 tertiary pediatric hospitals.There were 67 pediatric patients weighing <10 kg (36 boys; 31 girls; average age 202 days; average weight 6 kg, range 1.5-9.9 kg) referred for liver biopsy performed with ultrasound guidance and gelatin sponge pledget tract embolization during a 2-year period. Patient history, procedural records, and clinical follow-up documents were retrospectively reviewed.A total of 67 procedures were included. There was 100% technical success rate and all samples obtained provided adequate tissue for histological assessment. Average number of 18 G biopsy passes was 3 (range 1-6). There were no procedure-related deaths. There was 1 complication (1%) in a 5-kg infant who was readmitted 36 hours after biopsy with a fever and fully recovered after antibiotics were administered. Biliary atresia was the most common underlying diagnosis (20%), whereas others included acute rejection (16%) and biliary obstruction (7%).Ultrasound-guided percutaneous liver biopsy with gelatin sponge pledget tract embolization technique in children weighing <10 kg is safe, effective, and use of this technique may lead to a reduction in rates of adverse events reported in other pediatric series.
View details for PubMedID 27749391
Comparison of complications between pediatric peripherally inserted central catheter placement techniques.
2016; 46 (10): 1439-1443
Peripherally inserted central catheter (PICC) is among the most common procedures performed in children in the hospital setting. PICC insertion can be simplified with the use of a sheathed needle as an alternative to the modified Seldinger technique.To retrospectively evaluate PICC placement for the technique used and the incidence of complications at a large pediatric tertiary care center.We retrospectively reviewed all PICC placements at a single institution over a 4-year period. We reviewed patient records for demographic data, PICC placement technique, catheter size and number of lumens, and the incidence of complications (i.e. multiple attempted puncture sites, phlebitis and vessel thrombosis). We analyzed complication rates between two placement techniques using a chi-square test.We identified 8,816 successful PICC placements, 4,749 (53.9%) in males and 4,067 (46.1%) in females. The average age of the patients for which a line was placed was 5.6 years (range 1 day to 45 years). A direct sheathed needle puncture technique was used in 8,362 (94.9%) placements and a modified Seldinger technique was used in 454 (5.1%). Complications occurred in 312 (3.7%) of direct sheathed needle puncture placements versus 17 (3.7%) of modified Seldinger placements (P = 0.99). Multiple puncture sites were required in 175 (2.1%) attempted direct sheathed needle puncture placements compared with 8 (1.7%) attempted modified Seldinger placements (P = 0.63). Phlebitis occurred in 94 (1.1%) direct sheathed needle puncture lines versus 5 (1.1%) modified Seldinger placed lines (P = 0.96). Vessel thrombosis occurred in 43 (0.5%) direct sheathed needle puncture lines versus 4 (0.9%) modified Seldinger placed lines (P = 0.30).The direct peel-away sheathed needle vessel puncture technique and the modified Seldinger technique used to place PICC lines in children have similar complication rates.
View details for DOI 10.1007/s00247-016-3629-4
View details for PubMedID 27126700
White Paper on P4 Concepts for Pediatric Imaging
JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY
2016; 13 (5): 590-597
Over the past decade, innovations in the field of pediatric imaging have been based largely on single-center and retrospective studies, which provided limited advances for the benefit of pediatric patients. To identify opportunities for potential "quantum-leap" progress in the field of pediatric imaging, the ACR-Pediatric Imaging Research (PIR) Committee has identified high-impact research directions related to the P4 concept of predictive, preventive, personalized, and participatory diagnosis and intervention. Input from 237 members of the Society for Pediatric Radiology was clustered around 10 priority areas, which are discussed in this article. Needs within each priority area have been analyzed in detail by ACR-PIR experts on these topics. By facilitating work in these priority areas, we hope to revolutionize the care of children by shifting our efforts from unilateral reaction to clinical symptoms, to interactive maintenance of child health.
View details for DOI 10.1016/j.jacr.2015.10.028
View details for Web of Science ID 000375357700024
View details for PubMedID 26850380
Assessing the Risk of Hemorrhagic Complication following Transjugular Liver Biopsy in Bone Marrow Transplantation Recipients.
Journal of vascular and interventional radiology
2016; 27 (4): 551-557
To determine if recipients of bone marrow transplants (BMTs) are at increased risk of hemorrhagic complications following transjugular liver biopsy (TJLB).TJLBs in BMT and non-BMT patients between January 2007 and July 2014 were reviewed. Patient demographic and pre- and postprocedural laboratory data were reviewed. Mean platelet count and International Normalized Ratio were 174,300 × 10(3)/µL ± 107.3 (standard deviation) and 1.2 ± 0.4, respectively, for BMT recipients, compared with 88,100 × 10(3)/µL ± 70.9 and 1.2 ± 0.5, respectively, for non-BMT. Patients in whom hemoglobin level decreased by > 1 g/dL and/or required transfusion within 15 days of TJLB were reviewed to determine the presence of a biopsy-related hemorrhagic complication.A total of 1,600 TJLBs in 1,120 patients were analyzed. Of these, 183 TJLBs in 159 BMT recipients and 1,417 TJLBs in 961 patients non-BMT patients were performed. Thirteen TJLBs were complicated by hemorrhage: five in BMT (2.9%) and eight in the non-BMT cohorts (0.6%; P < .01). Preprocedural platelet counts were within normal range (57-268 × 10(3)/µL) in all but one patient (8 × 10(3)/µL). BMT recipients had an odds ratio of 4.9 (95% confidence interval, 1.25-17.3) for post-TJLB bleeding/hemorrhage compared with those without BMTs (P < .01).TJLB continues to be a safe procedure in the vast majority of patients. However, hemorrhagic complications occurred at a rate of 2.9% in BMT recipients, compared with 0.6% in patients without BMTs, and therefore caution should be exercised when performing TJLB in this group.
View details for DOI 10.1016/j.jvir.2016.01.007
View details for PubMedID 26948328
- Assessing the Risk of Hemorrhagic Complication following Transjugular Liver Biopsy in Bone Marrow Transplantation Recipients JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY 2016; 27 (4): 551-557
- Ultrasound-Guided Botulinum Toxin Type A Salivary Gland Injection in Children for Refractory Sialorrhea: 10-Year Experience at a Large Tertiary Children's Hospital PEDIATRIC NEUROLOGY 2016; 54: 70-75
Endovascular thrombolysis to salvage central venous access in children with catheter-associated upper extremity deep vein thrombosis: technique and initial results.
Journal of thrombosis and thrombolysis
2015; 40 (3): 274-279
Nine patients (average age 8.3 years, range 20 days to 17 years; average weight 31 kg, range 2.7-79 kg) with catheter-associated UE-DVT underwent upper extremity venous thrombolysis with the goal of access salvage. Catheter directed therapy with alteplase (tPA), balloon angioplasty, and mechanical thrombectomy was used in all cases. The mean total dose of TPA was 15 mg (range 1-40 mg). Venous access was ultimately preserved in all patients. No stents or superior vena cava filters were used. There was one episode of symptomatic clinically suspected pulmonary embolism managed by systemic tPA and heparin without long term sequaele. Mean imaging and clinical follow-up was 351 ± 208 and 613 ± 498 days respectively. Endovenous thrombolysis for catheter-associated upper-extremity DVT in children may be safe and effective and could be considered particularly in patients in whom long-term venous access is needed.
View details for DOI 10.1007/s11239-015-1209-3
View details for PubMedID 25894473
Transjugular Intrahepatic Portosystemic Shunt Complications: Prevention and Management
SEMINARS IN INTERVENTIONAL RADIOLOGY
2015; 32 (2): 123-132
Transjugular intrahepatic portosystemic shunt (TIPS) insertion has been well established as an effective treatment in the management of sequelae of portal hypertension. There are a wide variety of complications that can be encountered, such as hemorrhage, encephalopathy, TIPS dysfunction, and liver failure. This review article summarizes various approaches to preventing and managing these complications.
View details for DOI 10.1055/s-0035-1549376
View details for Web of Science ID 000355959400007
View details for PubMedID 26038620
Management of Dysfunctional Catheters and Tubes Inserted by Interventional Radiology
SEMINARS IN INTERVENTIONAL RADIOLOGY
2015; 32 (2): 67-77
Minimally invasive percutaneous interventions are often used for enteral nutrition, biliary and urinary diversion, intra-abdominal fluid collection drainage, and central venous access. In most cases, radiologic and endoscopic placement of catheters and tubes has replaced the comparable surgical alternative. As experience with catheters and tubes grows, it becomes increasingly evident that the interventional radiologist needs to be an expert not only on device placement but also on device management. Tube dysfunction represents the most common complication requiring repeat intervention, which can be distressing for patients and other health care professionals. This manuscript addresses the etiologies and solutions to leaking and obstructed feeding tubes, percutaneous biliary drains, percutaneous catheter nephrostomies, and drainage catheters, including abscess drains. In addition, we will address the obstructed central venous catheter.
View details for DOI 10.1055/s-0035-1549371
View details for Web of Science ID 000355959400002
View details for PubMedID 26038615
Isolated Upper Extremity Posttransplant Lymphoproliferative Disorder in a Child.
Case reports in radiology
2015; 2015: 813989-?
Posttransplant lymphoproliferative disorder (PTLD) is a well-described complication of solid organ and bone marrow transplants. The most common presentation is intra-abdominal lymphadenopathy or single or multiple intraparenchymal masses involving the liver, spleen, or kidneys. Here we describe the imaging and pathology findings of an unusual case of PTLD appearing as an intramuscular forearm lesion in a pediatric male. The manifestation of PTLD as an isolated upper extremity mass in a pediatric patient has to our knowledge not been described.
View details for DOI 10.1155/2015/813989
View details for PubMedID 26167324
Physician self-referral and imaging use appropriateness: negative cervical spine MRI frequency as an assessment metric.
AJNR. American journal of neuroradiology
2014; 35 (12): 2248-2253
Imaging self-referral is increasingly cited as a contributor to diagnostic imaging overuse. The purpose of this study was to determine whether ownership of MR imaging equipment by ordering physicians influences the frequency of negative cervical spine MR imaging findings.A retrospective review was performed of 500 consecutive cervical spine MRIs ordered by 2 separate referring-physician groups serving the same geographic community. The first group owned the scanners used and received technical fees for their use, while the second group did not. Final reports were reviewed, and for each group, the percentage of negative study findings and the frequency of abnormalities were calculated. The number of concomitant shoulder MRIs was recorded.Five hundred MRIs meeting inclusion criteria were reviewed (250 with financial interest, 250 with no financial interest). Three hundred fifty-two had negative findings (190 with financial interest, 162 with no financial interest); there were 17.3% more scans with negative findings in the financial interest group (P = .006). Among scans with positive findings, there was no significant difference in the mean number of lesions per scan, controlled for age (1.90 with financial interest, 2.19 with no financial interest; P = .23). Patients in the financial interest group were more likely to undergo concomitant shoulder MR imaging (24 with financial interest, 11 with no financial interest; P = .02).Cervical spine MRIs referred by physicians with a financial interest in the imaging equipment used were significantly more likely to have negative findings. There was otherwise a highly similar distribution and severity of disease between the 2 patient samples. Patients in the financial interest group were more likely to undergo concomitant shoulder MR imaging.
View details for DOI 10.3174/ajnr.A4076
View details for PubMedID 25104287
- Bacteriophage K Antimicrobial-Lock Technique for Treatment of Staphylococcus aureus Central Venous Catheter-Related Infection: A Leporine Model Efficacy Analysis JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY 2014; 25 (10): 1627-1632
- Global Health Imaging Curriculum in Radiology Residency Programs: The Fundamentals JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY 2014; 11 (10): 968-973
Ultrasound-guided interventions in children
EUROPEAN JOURNAL OF RADIOLOGY
2014; 83 (9): 1582-1591
There are a variety of available imaging modalities used for minimally invasive procedures in children, however, among the most frequently used is ultrasound (US). The advantages of US are vast and include real-time visualization, lack of ionizing radiation, and all-around versatility. US is also inexpensive, portable and widely available. In general US guided procedures in children have applications in nearly every aspect of medical therapy. Properly trained practitioners with US imaging experience and detailed knowledge of the relevant anatomy provide an invaluable service to the care of pediatric patients in many centers. This paper will discuss many of the image guided procedures that are performed in children and offer practical techniques from the collective experience of our practice at a large pediatric tertiary care center.
View details for DOI 10.1016/j.ejrad.2014.04.021
View details for Web of Science ID 000340834800011
View details for PubMedID 24932844
Endovascular Venous Thrombolysis in Children Younger than 24 Months
JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY
2014; 25 (8): 1158-1164
To evaluate the technical feasibility and safety of percutaneous endovascular thrombolysis for extremity deep venous thrombosis (DVT) in children < 24 months old.A retrospective chart review of a clinical and imaging database was performed for pediatric patients who underwent endovascular therapy for DVT between January 2010 and July 2013. Indications, techniques, technical and clinical success, and complications were reviewed. Techniques for thrombolysis included catheter-directed therapy (CDT) using alteplase infusion via a multi-side hole catheter, mechanical thrombectomy, and angioplasty. Short-term outcomes were assessed using surgical and imaging follow-up examinations for patency of the targeted vessel. Patients included 11 children (mean age, 9 mo; range, 3 wk-23 mo) who consecutively underwent endovascular thrombolysis for upper extremity (n = 6) or lower extremity (n = 5) DVT. The most common indication was preservation of venous access for future cardiac surgery or medical therapy.The most common risk factor was the presence of a central venous catheter (10 of 11 patients). All patients with upper extremity DVT had congenital heart disease. CDT and angioplasty were performed in all patients. Venous patency was established in all patients. A grade III (95%-100%) thrombolysis response was achieved in seven patients, and a grade II (50%-95%) thrombolysis response was achieved in four patients. A major complication of pulmonary embolism occurred in one patient with upper extremity thrombolysis and was managed by intravenous systemic alteplase and heparin. No recurrence of thrombosis was found on average follow-up of 11.8 months (range, 1-41 mo).Percutaneous endovascular thrombolysis for extremity DVT is safe and technically feasible in children < 24 months old.
View details for DOI 10.1016/j.jvir.2014.04.003
View details for Web of Science ID 000339780300002
View details for PubMedID 24909354
Assessment of vascular contrast and wall motion of the aortic root and ascending aorta on MDCT angiography: dual-source high-pitch vs non-gated single-source acquisition schemes
2014; 24 (5): 990-997
This retrospective study assessed whether dual-source high-pitch computed tomographic angiography (CTA) offered advantages over single-source standard-pitch techniques in the evaluation of the ascending aorta.Twenty patients who received both thoracic dual-source high-pitch and single-source standard-pitch CTAs within 1 year were assessed. Dual-source CTAs were performed; standard-pitch imaging used dose-modulated 120 kVp/150 mAs and 0.8 pitch compared with high-pitch protocols employing dose-modulated 120 kVp/250 mAs and 2.4 target pitch. Radiation dose was documented. Contrast-to-noise ratios (CNRs) at sinuses of the Valsalva (CNRValsalva) and ascending aorta (CNRAorta) were calculated. Dose/CNR for each technique was compared with paired t-tests. Motion at aortic valve, aortic root and ascending aorta were assessed with four-point scales and Mann-Whitney U tests; longitudinal extension of motion was compared with paired t-tests.Significantly lower motion scores for high-pitch, compared with standard-pitch acquisitions for aortic annulus, 0 vs. 2, aortic root, 0 vs. 3, and ascending aorta, 0 vs. 2, were achieved. Significantly reduced longitudinal extension of motion at aortic root, 4.9 mm vs 15.7 mm, and ascending aorta, 4.9 mm vs 21.6 mm, was observed. Contrast was not impacted: CNRValsalva, 45.6 vs 46.3, and CNRAorta, 45.3 vs 47.1. CTDIvol was significantly decreased for high-pitch acquisitions, 13.9 mGy vs 15.8 mGy.Dual-source high-pitch CTAs significantly decreased motion artefact without negatively impacting vascular contrast and radiation dose.• Dual-source high-pitch CTA significantly decreased motion artefact of the ascending aorta. • Dual-source high-pitch CTA did not negatively impact on vascular contrast. • Dual-source high-pitch CTA significantly decreased radiation dose compared with single-source standard-pitch acquisitions.
View details for DOI 10.1007/s00330-014-3120-2
View details for Web of Science ID 000334182100003
View details for PubMedID 24573567
Bacteriophage K antimicrobial-lock technique for treatment of Staphylococcus aureus central venous catheter-related infection: a leporine model efficacy analysis.
Journal of vascular and interventional radiology : JVIR
2014; 25 (10): 1627–32
To determine whether a bacteriophage antimicrobial-lock technique can reduce bacterial colonization and biofilm formation on indwelling central venous catheters in a rabbit model.Cuffed central venous catheters were inserted into the jugular vein of female New Zealand White rabbits under image guidance. Catheters were inoculated for 24 hours with broth culture of methicillin-sensitive Staphylococcus aureus. The inoculum was aspirated, and rabbits were randomly assigned to two equal groups for 24 hours: (i) untreated controls (heparinized saline lock), (ii) bacteriophage antimicrobial-lock (staphylococcal bacteriophage K, propagated titer > 10(8)/mL). Blood cultures were obtained via peripheral veins, and the catheters were removed for quantitative culture and scanning electron microscopy.Mean colony-forming units (CFU) per cm(2) of the distal catheter segment, as a measure of biofilm, were significantly decreased in experimental animals compared with controls (control, 1.2 × 10(5) CFU/cm(2); experimental, 7.6 × 10(3); P = .016). Scanning electron microscopy demonstrated that biofilms were present on the surface of five of five control catheters but only one of five treated catheters (P = .048). Blood culture results were not significantly different between the groups.In a rabbit model, treatment of infected central venous catheters with a bacteriophage antimicrobial-lock technique significantly reduced bacterial colonization and biofilm presence. Our data represent a preliminary step toward use of bacteriophage therapy for prevention and treatment of central venous catheter-associated infection.
View details for DOI 10.1016/j.jvir.2014.06.009
View details for PubMedID 25088065
Global health imaging curriculum in radiology residency programs: the fundamentals.
Journal of the American College of Radiology : JACR
2014; 11 (10): 968–73
Recent advances in imaging technology have created new opportunities for medical imaging to improve health care in resource-restricted countries around the world. Radiology residents are increasingly interested in global health and imaging outreach, yet infrastructure and opportunities for international outreach are limited. With the recent change in the ABR exam schedule, residents now have more flexibility in the fourth year of training to pursue elective interests, including participation in global health projects. Creating a formalized global health imaging curriculum will improve the quality, quantity, and overall impact of initiatives undertaken by residents and their training programs. A curriculum is proposed that provides content, opportunities for global health project development, and established metrics for effective evaluation and assessment. Four components considered integral to a global health imaging curriculum are described: (1) global and public health education; (2) targeted travel medicine education; (3) basic imaging proficiency; and (4) practice attitudes and accountability. Methods are presented of differentiating curricula to increase applicability across the spectrum of training programs that vary in available resources. A blueprint is presented for formalizing a global health curriculum or elective rotation within a program, as well as a resource for residents, radiologists, and organizations to make a meaningful impact on global health.
View details for DOI 10.1016/j.jacr.2014.04.007
View details for PubMedID 24933449
Comparison of Primary Jejunostomy Tubes versus Gastrojejunostomy Tubes for Percutaneous Enteral Nutrition
JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY
2013; 24 (12): 1845-1852
To evaluate technical success and long-term outcomes of percutaneous primary jejunostomy tubes for postpyloric enteral feeding compared with percutaneous gastrojejunostomy (GJ) tubes.Over a 25-month interval, 41 consecutive patients (26 male; mean age, 55.9 y) underwent attempted fluoroscopy-guided direct percutaneous jejunostomy tube insertion. Insertions at previous jejunostomy tube sites were excluded. The comparison group consisted of all primary GJ tube insertions performed over a 12-month interval concomitant with the jejunostomy tube interval (N = 169; 105 male; mean age, 59.4 y). Procedural, radiologic, and clinical data were retrospectively reviewed. Intervention rates were expressed as events per 100 catheter-days.The technical success rate for percutaneous jejunostomy tube insertion was 96%, versus 93% for GJ tubes (P = .47). Mean fluoroscopy times were similar for jejunostomy and GJ tubes (9.8 vs 10.0 min, respectively; P value not significant). Jejunostomy tubes exhibited a lower rate of catheter dysfunction than GJ tubes, with catheter exchange rates of 0.24 versus 0.93, respectively, per 100 catheter-days (P = .045). GJ tube tip retraction into the stomach occurred in 9.5% of cases, at a rate of 0.21 per 100 catheter-days. Intervention rates related to leakage were 0.19 and 0.03 for jejunostomy and GJ tubes, respectively (P < .01). Jejunostomy and GJ tubes exhibited similar rates of catheter exchange for occlusion and replacement as a result of inadvertent removal. No major complications were encountered in either group.Percutaneous insertion of primary jejunostomy tubes demonstrated technical success and complication rates similar to those of GJ tubes. Jejunostomy tubes exhibited a lower dysfunction rate but a higher leakage rate compared with GJ tubes.
View details for DOI 10.1016/j.jvir.2013.08.012
View details for Web of Science ID 000327808700013
View details for PubMedID 24094674
Physician Self-Referral: Frequency of Negative Findings at MR Imaging of the Knee as a Marker of Appropriate Utilization
2013; 269 (3): 810-815
To determine whether ownership of magnetic resonance (MR) imaging equipment by ordering physicians affects the likelihood of positive findings at MR imaging of the knee and to evaluate rates of knee abnormalities seen at MR imaging as a metric for comparison of utilization.The institutional review board approved this retrospective HIPAA-compliant study and waived the need for informed consent. A retrospective review was performed of consecutive diagnostic MR images of the knee interpreted by one radiology practice between January and April 2009 for patients who had been referred by two separate physician groups serving the same geographic community: one with financial interest (FI) in the MR imaging equipment used and one with no FI (NFI) in the MR imaging equipment used. The percentage of examinations with negative results was tabulated for both groups, and the relative frequency of each abnormality subtype was calculated among the studies with positive findings in each group. To examine frequency differences among groups, χ(2) tests were used, and to examine mean differences among groups, t tests were used.Of 700 examinations, 205 had negative results (117 of 350 in the FI group and 88 of 350 in the NFI group, P = .016). Among the examinations with positive results, the mean total number of positive abnormality subtypes per image did not significantly differ between groups: 1.52 for the FI group and 1.53 for the NFI group (P = .96).MR images of the knee among patients referred by the FI group were significantly more likely to be negative than those among patients referred by the NFI group. Frequency of abnormality subtype and distribution among examinations with positive results suggests a highly similar distribution and severity of abnormalities between the two patient groups.
View details for DOI 10.1148/radiol.13130281
View details for Web of Science ID 000327761100021
View details for PubMedID 24046441
- Imaging Self-Referral: Here We Go Again AMERICAN JOURNAL OF ROENTGENOLOGY 2013; 201 (4): W658-W658
Impact of phase of respiration on central venous catheter tip position
JOURNAL OF VASCULAR ACCESS
2013; 14 (4): 383-387
To determine the impact of the phase of respiration on CVC tip position using cross-sectional imaging.We retrospectively analyzed the CT scans of 24 consecutive patients (eight men and 16 women, mean age 56.3 years, range 18-79) who underwent a CT scan protocol that includes both imaging of the thorax in inspiration and expiration. Only patients with a central venous catheter and absence of any substantial pulmonary pathology that might affect lung volumes were included. Measurements of the catheter tip location and central venous structures were obtained from inspiratory and expiratory phase images in each patient and compared using the paired t test.The length of the SVC and superior mediastinum were significantly longer during inspiration compared to expiration (9 mm and 7 mm respectively, P<0.001 for both). The distance between the superior and inferior cavo-atrial junction did not change significantly with respiration. The catheter tip location moved on average 9 mm (range 0-25 mm) cephalad during inspiration compared to expiration (P=0.001) in relation to the superior cavoatrial junction. The amount of catheter tip movement correlated significantly with the degree of diaphragmatic excursion with respiration (R=0.58). During inspiration, the cavo-atrial junction was on average 11 mm inferior to the right cardiomediastinal angle observed on radiography, but was nearly identical during expiration (R=0.78, P<0.001).The central catheter tip position varied significantly with respiratory motion, with a mean excursion of 9 mm. The right cardiomediastinal border demonstrated a strong correlation with the actual location of the superior cavo-atrial junction in expiration, but not in inspiration.
View details for DOI 10.5301/jva.5000135
View details for Web of Science ID 000329565700013
View details for PubMedID 23599138
Tunneled Peritoneal Drainage Catheter Placement for Refractory Ascites: Single-center Experience in 188 Patients
JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY
2013; 24 (9): 1303-1308
To assess the success and safety of tunneled peritoneal drainage catheters for the management of ascites refractory to medical management.A total of 188 consecutive patients (83 male, 105 female; average age 59 y) with refractory ascites were treated with tunneled peritoneal drainage catheters from January 1, 2006, to August 10, 2012. A combination of fluoroscopic and ultrasound guidance was used to insert all catheters. Patient history, procedural records, and clinical follow-up documents were retrospectively reviewed. Clinical data (malignancy, renal disease, chemotherapy, neutropenia, albumin levels) were compared with respect to patency and complication rates with the use of odds ratios. Catheter survival curves were generated with the Kaplan-Meier method and life-table analysis for the cumulative and infection-free survival of primary and secondary catheters.A total of 193 catheter placements or interventions were performed in 188 patients with refractory ascites: 170 catheters (93%) were placed for malignant etiologies and 13 (7%) for nonmalignant etiologies. The most common malignancies were ovarian (22%), pancreatic (12%), and breast (11%). The most common nonmalignant etiologies were end-stage liver disease (n = 7) and heart failure (n = 6). There was a 100% technical success rate for catheter insertion; no procedure-related deaths or major placement complications were identified. Catheter survival ranged from 0 to 796 days (mean, 60 d), with a total of 11,936 cumulative catheter-days. Fourteen postplacement complications were identified: five patients experienced catheter malfunction, four had leakage of ascites at the incisional site requiring suture placement, three had cellulitis of the tunnel tract, and two developed peritonitis. The annual complication event rate was 0.43 events per year (ie, 0.12 events per 100 catheter-days). Pancreatic malignancy was associated with a significantly increased rate of catheter malfunction (ie, occlusion).Radiologic insertion of tunneled peritoneal drainage catheters demonstrated a 100% technical success rate for insertion and an acceptable complication rate for the management of refractory ascites.
View details for DOI 10.1016/j.jvir.2013.05.042
View details for Web of Science ID 000324363600008
View details for PubMedID 23876552
Journal Club: Shoulder MRI utilization: relationship of physician MRI equipment ownership to negative study frequency.
AJR. American journal of roentgenology
2013; 201 (3): 605-610
The purpose of this article is to determine whether ownership of MRI equipment by ordering physicians influences the frequency of negative shoulder MRI scans.A retrospective review was performed of 1140 consecutive shoulder MRI scans ordered by two separate referring physician groups serving the same geographic community. The first group (financially incentivized) owned the scanners used and received technical fees for their use. The second group (non-financially incentivized) did not own the scanners used and had no direct financial interest. All examinations were performed with identical protocols and were interpreted by a single radiologist group without financial interest in the imaging equipment used. The frequency of negative examinations and the number of abnormalities in each positive study was tabulated for each group.A total of 1140 shoulder MRI scans met inclusion criteria; 255 were negative (142 for the financially incentivized group and 113 for the non-financially incentivized group). There were 25.6% more negative scans in the financially incentivized group (p=0.047). There was no statistically significant difference in the average number of lesions per positive scan (1.67 for the financially incentivized group and 1.71 for the non-financially incentivized group; p=0.34). No statistically significant difference was found in the frequency of 19 of 20 examined lesions.Shoulder MRI examinations referred by physicians with a financial interest in the imaging equipment used were significantly more likely to be negative. Positive examinations exhibited no statistically significant difference in the number of lesions per scan or in the frequency of 19 of 20 lesion subtypes. This finding suggests a highly similar distribution and severity of disease among the two patient groups.
View details for DOI 10.2214/AJR.12.9977
View details for PubMedID 23971453
White Paper Report of the 2012 RAD-AID Conference on International Radiology for Developing Countries: Planning the Implementation of Global Radiology
JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY
2013; 10 (8): 618-624
The RAD-AID Conference on International Radiology for Developing Countries is a yearly forum addressing global shortages of radiology that contribute to health care disparity. In this paper, the authors present key issues and consensus positions related to the planning, analyzing, implementing, and monitoring of radiology in limited-resource areas on the basis of presentations at the 2012 RAD-AID conference, to advocate for (1) economic development to build health care capacity, (2) multidisciplinary educational strategies, (3) innovative epidemiologic and infrastructural solutions tailored to community needs, (4) advanced technical solutions leveraging the widespread use of wireless telecommunications and phone-based portable devices, and (5) improved dialog across radiology and public health institutions for coordinating global health strategies.
View details for DOI 10.1016/j.jacr.2013.01.019
View details for Web of Science ID 000323397000015
View details for PubMedID 23583085
- Single-Incision Technique for Placing Femoral Tunneled Central Venous Catheters in Infants JOURNAL OF VASCULAR AND INTERVENTIONAL RADIOLOGY 2013; 24 (5): 755-756
- Radiology Education in China JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY 2013; 10 (3): 213-219
Bacteriophage K for reduction of Staphylococcus aureusbiofilm on central venous catheter material.
2013; 3 (4): e26825
The purpose of this project was to determine whether bacteriophage can reduce bacterial colonization and biofilm formation on central venous catheter material. Twenty silicone discs were inoculated for 24 h with broth culture of Methicillin sensitive staphylococcus aureus (0.5 McFarland standard). The inoculate was aspirated and discs placed into two equal groups for 24 h: (1) untreated controls; (2) bacteriophage treatment (staphylococcal bacteriophage K, propagated titer > 10(8)). At the completion of the experiment discs were processed for quantitative culture. Statistical testing was performed using the rank sum test. Mean colony forming units (CFU) were significantly decreased in experimental compared with controls (control 6.3 × 10(5) CFU, experimental 6.7 × 10(1), P ≤ 0.0001). Application of bacteriophage to biofilm infected central venous catheter material significantly reduced bacterial colonization and biofilm presence. Our data suggests that bacteriophage treatment may be a feasible strategy for addressing central venous catheter staph aureus biofilm infections.
View details for DOI 10.4161/bact.26825
View details for PubMedID 24265979
Gray-scale inversion radiographic display for the detection of pulmonary nodules on chest radiographs
2012; 36 (5): 515-521
The purpose of this study was to investigate gray-scale inversion in nodule detection on chest radiography. Simulated nodules were superimposed randomly onto normal chest radiographs. Six radiologists interpreted 144 chest radiographs during three reading sessions: traditional presentation, inverted gray-scale, and a choice session allowing use of traditional and gray-scale inverted views. Sensitivity and specificity were used to assess accuracy based on presence or absence of a nodule. Gray-scale inversion and choice display sessions resulted in significantly higher nodule detection specificity and decreased sensitivity compared to traditional display. Gray-scale inversion may decrease false-positive nodule findings during chest X-ray interpretation.
View details for DOI 10.1016/j.clinimag.2012.01.009
View details for Web of Science ID 000308455200014
View details for PubMedID 22920355
Extrarenal Retroperitoneal Angiomyolipoma Mimicking Metastatic Melanoma CT and FDG PET Correlation
CLINICAL NUCLEAR MEDICINE
2012; 37 (7): 705-706
A 38-year-old man with melanoma of the right flank underwent a staging 18F-fluoro-2-deoxyglucose (FDG) PET/CT scan, which demonstrated a hypermetabolic extrarenal mass in the left retroperitoneal space, concerning for metastatic melanoma. However, surgical pathology demonstrated an angiomyolipoma (AML). Although AMLs can rarely occur in an extrarenal location, extrarenal retroperitoneal AMLs are exceptional. AMLs have variable imaging appearances on multiple imaging modalities, including FDG PET, and can confound accurate diagnosis when in an extrarenal location. This case demonstrates the only known FDG PET description of an extrarenal retroperitoneal AML and highlights the challenge in accurate diagnosis based on FDG PET findings.
View details for DOI 10.1097/RLU.0b013e3182443c7d
View details for Web of Science ID 000305290900025
View details for PubMedID 22691521
White Paper Report of the 2011 RAD-AID Conference on International Radiology for Developing Countries: Integrating Multidisciplinary Strategies for Imaging Services in the Developing World
JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY
2012; 9 (7): 488-494
The 2011 RAD-AID Conference on International Radiology for Developing Countries discussed data, experiences, and models pertaining to radiology in the developing world, where widespread shortages of imaging services significantly reduce health care quality and increase health care disparities. This white paper from the 2011 RAD-AID conference represents consensus advocacy of multidisciplinary strategies to improve the planning, accessibility, and quality of imaging services in the developing world. Conference presenters and participants discussed numerous solutions to imaging and health care disparities, including (1) economic development for radiologic service planning, (2) public health mechanisms to address disease and prevention at the population and community levels, (3) comparative clinical models to implement various clinical and workflow strategies adapted to unique developing world community contexts, (4) education to improve training and optimize service quality, and (5) technology innovation to bring new technical capabilities to limited-resource regions.
View details for DOI 10.1016/j.jacr.2012.01.005
View details for Web of Science ID 000306535000012
View details for PubMedID 22748790
Radiation Dose Estimations to the Thorax Using Organ-Based Dose Modulation
AMERICAN JOURNAL OF ROENTGENOLOGY
2012; 199 (1): W65-W73
The purpose of this study was to assess the radiation dose distribution and image quality for organ-based dose modulation during adult thoracic MDCT.Organ doses were measured using an anthropomorphic adult female phantom containing 30 metal oxide semiconductor field-effect transistor detectors on a dual-source MDCT scanner with two protocols: standard tube current modulation thoracic CT and organ-based dose modulation using a 120° radial arc. Radiochromic film measured the relative axial dose. Noise was measured to evaluate image quality. Breast tissue location across the anterior aspect of the thorax was retrospectively assessed in 100 consecutive thoracic MDCT examinations.There was a 17-47% decrease (p = < 0.05) in anterior thoracic organ dose and a maximum 52% increase (p = < 0.05) in posterior thoracic organ dose using organ-based dose modulation compared with tube current modulation. Effective dose (SD) for tube current modulation and organ-based dose modulation were 5.25 ± 0.36 mSv and 4.42 ± 0.30 mSv, respectively. Radiochromic film analysis showed a 30% relative midline anterior-posterior gradient. There was no statistically significant difference in image noise. Adult female breast tissue was located within an average anterior angle of 155° (123-187°).Organ-based dose modulation CT using an anterior 120° arc can reduce the organ dose in the anterior aspect of the thorax with a compensatory organ dose increase posteriorly without impairment of image quality. Laterally located breast tissue will have higher organ doses than medially located breast tissue when using organ-based dose modulation. The benefit of this dose reduction must be clinically determined on the basis of the relationship of the irradiated organs to the location of the prescribed radial arc used in organ-based dose modulation.
View details for DOI 10.2214/AJR.11.7798
View details for Web of Science ID 000305804000008
View details for PubMedID 22733933
Physician Self-Referral of Lumbar Spine MRI With Comparative Analysis of Negative Study Rates as a Marker of Utilization Appropriateness
AMERICAN JOURNAL OF ROENTGENOLOGY
2012; 198 (6): 1375-1379
Financial interest in imaging equipment may affect the imaging referral patterns of ordering physicians. The purpose of this article is to determine whether ownership of MRI equipment by ordering physicians predicts the likelihood and prevalence of positive findings on lumbar spine MRI as a metric for comparison of utilization.A retrospective review was performed of 500 consecutive diagnostic lumbar spine MRI examinations in one radiology practice ordered by two separate referring physician groups serving the same geographic community: one with financial interest in the MRI equipment used (financial-interest group) and one without financial interest in the MRI equipment used (no-financial-interest group). Negative examinations and total number of lesions per positive study were recorded for each group.Five hundred scans met inclusion criteria during the study period (250 in the financial-interest group and 250 in the no-financial-interest group). The negative scan frequency was 86% higher in the financial-interest group (p < 0.0001). Among positive scans, there was no significant difference in the average total number of positive lesions per scan (3.93 for the financial-interest group and 4.31 for the no-financial-interest group; p = 0.132). The average age of patients imaged by the financial-interest group was 49.8 years, versus 56.9 years for the no-financial-interest group (p < 0.0001).Lumbar spine MRI examinations referred by the financial-interest group were significantly more likely to be negative than those referred by the no-financial-interest group. Lesion frequency among positive scans suggests similar severity of disease between the two patient populations. Patients imaged by the financial-interest group were significantly younger than those imaged by the no-financial-interest group.
View details for DOI 10.2214/AJR.11.7730
View details for Web of Science ID 000304397500042
View details for PubMedID 22623551
- PET Appearance of Tuberculous Empyema Necessitans CLINICAL NUCLEAR MEDICINE 2011; 36 (10): 939-941
White Paper Report of the 2010 RAD-AID Conference on International Radiology for Developing Countries: Identifying Sustainable Strategies for Imaging Services in the Developing World
JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY
2011; 8 (8): 556-562
The 2010 RAD-AID Conference on International Radiology for Developing Countries was a multidisciplinary meeting to discuss data, experiences, and models pertaining to radiology in the developing world, where widespread shortages of imaging services reduce health care quality. The theme of this year's conference was sustainability, with a focus on establishing and maintaining imaging services in resource-limited regions. Conference presenters and participants identified 4 important components of sustainability: (1) sustainable financing models for radiology development, (2) integration of radiology and public health, (3) sustainable clinical models and technology solutions for resource-limited regions, and (4) education and training of both developing and developed world health care personnel.
View details for DOI 10.1016/j.jacr.2011.01.011
View details for Web of Science ID 000306201600009
View details for PubMedID 21807349
Self-Referral in Medical Imaging: A Meta-Analysis of the Literature
JOURNAL OF THE AMERICAN COLLEGE OF RADIOLOGY
2011; 8 (7): 469-476
In the current political and economic climate, there is a desire to reduce health care costs; diagnostic imaging expenditure is one area of particular interest. The authors present a meta-analysis of the relative frequency of imaging utilization in the setting of self-referral compared with that of non-self-referral and a simulation of increased cost to Medicare Part B on the basis of this relative frequency.The MEDLINE database was searched systematically. Specific inclusion criteria for relative frequency calculations were a numerator (number of patients imaged) and denominator (number of total patients seen) in each group (self-referrers and radiologist referrers). The relative risk of self-referral was determined for each group and is defined by the "relative frequency" of imaging utilization for the self-referrers divided by the frequency for the radiologist referrers. Relative frequency represents the increased (if >1) or decreased (if <1) chance of imaging by self-referrers over radiologist referrers. The meta-analysis was used to combine imaging frequencies for each referral condition of the individual studies that met inclusion criteria for an overall estimate of relative frequency, using a random-effects model to account for the variations among the studies. Relative frequency data were then used to perform a cost simulation to Medicare Part B using 2006 data.The initial search yielded 334 articles, 5 of which met the threshold for inclusion. In these 5 studies, 76,905,162 total episodes of care were analyzed. The individual relative frequency of imaging in the setting of self-referral ranged from 1.60 to 4.50. The combined relative frequency was 2.16 (95% confidence interval, 2.15-2.16) using the fixed-effects model and 2.48 (95% confidence interval, 1.90-3.24) using the random-effects model. For 2006 Government Accountability Office (GAO) data, the estimated cost of increased imaging in the setting of self-referral was $3.6 billion, but a range of costs was also provided to account for potential inaccuracies in the GAO data.The existing literature yields a combined relative frequency of imaging of 2.48 (95% confidence interval, 1.90-3.24) for self-referrers compared with non-self-referrers. Precise extrapolation of Medicare Part B costs attributable to self-referral would require changes in reporting requirements for imaging equipment ownership. Cost simulation results total billions of dollars annually and may be irrespective of potential inaccuracies in the GAO data as a result of Current Procedural Terminology(®) coding ambiguity and nontransparent reporting of equipment ownership.
View details for DOI 10.1016/j.jacr.2011.01.016
View details for Web of Science ID 000306201500007
View details for PubMedID 21723483
Global Health Training in Radiology Residency Programs
2011; 18 (6): 782-791
To measure perceptions of radiology residents regarding the imaging needs of the developing world and the potential role of an organized global health imaging curriculum during residency training.An electronic survey was created and then distributed to residents in accredited US radiology residency.Two hundred ninety-four residents responded to the survey. A majority (61%) planned to pursue future international medical aid work, even though a similar proportion (59%) believed that they would be ill-prepared with their current training to pursue this career goal. The vast majority (91%) of respondents stated that their residency program offers no opportunities to participate in global health imaging experiences. Most surveyed residents felt that an organized global health imaging curriculum would improve understanding of basic disease processes (87%) and cost-conscious care (82%), prepare residents for lifelong involvement in global health (80%), and increase interpretative skills in basic radiology modalities (73%). If such a curriculum were available, most (62%) of surveyed residents stated that they would be likely or very likely to participate. Many (58%) believed the availability of such a program would have influenced their choice of residency program; a similar proportion of residents (75%) believed that the availability of a global health imaging curriculum would increase recruitment to the field of radiology.Many radiology residents are motivated to acquire global health imaging experience, with most survey respondents planning to participate in global health initiatives. These data demonstrate an imbalance between the level of resident interest and the availability of global health imaging opportunities, and support the need for discussion on how to implement global health imaging training within radiology residency programs.
View details for DOI 10.1016/j.acra.2011.02.009
View details for Web of Science ID 000290976900018
View details for PubMedID 21458308
White Paper Report of the RAD-AID Conference on International Radiology for Developing Countries: identifying challenges, opportunities, and strategies for imaging services in the developing world.
Journal of the American College of Radiology
2010; 7 (7): 495-500
The RAD-AID Conference on International Radiology for Developing Countries was an assembly of individuals and organizations interested in improving access to medical imaging services in developing countries where the availability of radiology has been inadequate for both patient care and public health programs. The purpose of the meeting was to discuss data, experiences, and models pertaining to radiology in the developing world and to evaluate potential opportunities for future collaboration. Conference participants included radiologists, technologists, faculty members of academic medical institutions, and leadership of nongovernmental organizations involved in international health care and social entrepreneurship. Four main themes from the conference are presented in this white paper as important factors for the implementation and optimization of radiology in the developing world: (1) ensuring the economic sustainability of radiologic services through financial and administrative training support of health care personnel; (2) designing, testing, and deploying clinical strategies adapted for regions with limited resources; (3) structuring and improving the role of American radiology residents interested in global health service projects; and (4) implementing information technology models to support digital imaging in the developing world.
View details for DOI 10.1016/j.jacr.2010.01.018
View details for PubMedID 20630383
- Isolated intracranial Rosai-Dorfman disease in a child. AJNR. American journal of neuroradiology 2009; 30 (10): E148-9
Fiber type composition and maximum shortening velocity of muscles crossing the human shoulder
2007; 20 (2): 144-149
A study of the fiber type composition of fourteen muscles spanning the human glenohumeral joint was carried out with the purpose of determining the contribution of fiber types to overall muscle cross-sectional area (CSA) and to estimate the maximum shortening velocity (V(max)) of those muscles. Muscle biopsies were procured from 4 male cadavers (mean age 50) within 24 hr of death, snap frozen, mounted, and transversely sectioned (10 microm). Slides were stained for myofibrillar ATPase after alkaline preincubation. Photoimages were taken of defined areas (100 fibers) using the Bioquant system, and fiber type and CSA were measured from these images. Staining for mATPase produced three different fiber types: slow-oxidative (SO), fast-oxidative-glycolytic (FOG), and fast-glycolytic (FG). On average, the muscle fiber type composition ranged from 22 to 40% of FG, from 17 to 51% of FOG, and from 23 to 56% of SO. Twelve out of the 14 muscles had average SO proportions ranging from 35 to 50%. V(max) was calculated from the fiber type contribution relative to CSA and shortening velocity values taken from the literature. The maximum velocities of shortening presented here provide a physiological basis for the development of human shoulder musculoskeletal models suitable for predicting muscle forces for functionally relevant tasks encompassing conditions of muscle shortening and lengthening.
View details for DOI 10.1002/ca.20349
View details for Web of Science ID 000244139100008
View details for PubMedID 16795030
Using support vector machines to optimally classify rotator cuff strength data and quantify post-operative strength in rotator cuff tear patients
JOURNAL OF BIOMECHANICS
2006; 39 (5): 973-979
Shoulder strength data are important for post-operative assessment of shoulder function and have been used in diagnosis of rotator cuff pathology. Support vector machines (SVM) employ complex analysis techniques to solve classification and regression problems. A SVM, a machine learning technique, can be used for analysis and classification of shoulder strength data. The goals of this study were to determine the diagnostic competency of SVM based on shoulder strength data and to apply SVM analysis in efforts to derive a single representative shoulder strength score. Data were taken from fourteen isometric shoulder strength measurements of each shoulder (involved and uninvolved) in 45 rotator cuff tear patients. SVM diagnostic proficiency was found to be comparable to reported ultrasound values. Improvement of shoulder function was accurately represented by a single score in pairwise comparison of the pre-operative and the 12 month post-operative group (P < 0.004). Thus, the SVM-based score may be a promising metric for summarizing rotator cuff strength data.
View details for DOI 10.1016/j.jbiomech.2005.01.011
View details for Web of Science ID 000236088200021
View details for PubMedID 16488235