Honors & Awards


  • F31 Predoctoral Fellowship, NIH
  • Graduate Research Fellowship Program, National Science Foundation
  • TBI2 Fellow, Radiological Sciences Laboratory

Professional Education


  • Doctor of Philosophy, Stanford University, BIOE-PHD (2023)
  • Master of Science, Stanford University, BIOE-MS (2020)
  • Bachelor of Arts and Sciences, Dartmouth College, Engineering Sciences

Lab Affiliations


All Publications


  • PET Imaging of Innate Immune Activation Using 11C Radiotracers Targeting GPR84. JACS Au Kalita, M., Park, J. H., Kuo, R. C., Hayee, S., Marsango, S., Straniero, V., Alam, I. S., Rivera-Rodriguez, A., Pandrala, M., Carlson, M. L., Reyes, S. T., Jackson, I. M., Suigo, L., Luo, A., Nagy, S. C., Valoti, E., Milligan, G., Habte, F., Shen, B., James, M. L. 2023; 3 (12): 3297-3310

    Abstract

    Chronic innate immune activation is a key hallmark of many neurological diseases and is known to result in the upregulation of GPR84 in myeloid cells (macrophages, microglia, and monocytes). As such, GPR84 can potentially serve as a sensor of proinflammatory innate immune responses. To assess the utility of GPR84 as an imaging biomarker, we synthesized 11C-MGX-10S and 11C-MGX-11Svia carbon-11 alkylation for use as positron emission tomography (PET) tracers targeting this receptor. In vitro experiments demonstrated significantly higher binding of both radiotracers to hGPR84-HEK293 cells than that of parental control HEK293 cells. Co-incubation with the GPR84 antagonist GLPG1205 reduced the binding of both radiotracers by >90%, demonstrating their high specificity for GPR84 in vitro. In vivo assessment of each radiotracer via PET imaging of healthy mice illustrated the superior brain uptake and pharmacokinetics of 11C-MGX-10S compared to 11C-MGX-11S. Subsequent use of 11C-MGX-10S to image a well-established mouse model of systemic and neuro-inflammation revealed a high PET signal in affected tissues, including the brain, liver, lung, and spleen. In vivo specificity of 11C-MGX-10S for GPR84 was confirmed by the administration of GLPG1205 followed by radiotracer injection. When compared with 11C-DPA-713-an existing radiotracer used to image innate immune activation in clinical research studies-11C-MGX-10S has multiple advantages, including its higher binding signal in inflamed tissues in the CNS and periphery and low background signal in healthy saline-treated subjects. The pronounced uptake of 11C-MGX-10S during inflammation, its high specificity for GPR84, and suitable pharmacokinetics strongly support further investigation of 11C-MGX-10S for imaging GPR84-positive myeloid cells associated with innate immune activation in animal models of inflammatory diseases and human neuropathology.

    View details for DOI 10.1021/jacsau.3c00435

    View details for PubMedID 38155640

    View details for PubMedCentralID PMC10751761

  • Temporal tau asymmetry spectrum influences divergent behavior and language patterns in Alzheimer`s disease. medRxiv : the preprint server for health sciences Younes, K., Smith, V., Johns, E., Carlson, M. L., Winer, J., He, Z., Henderson, V. W., Greicius, M. D., Young, C. B., Mormino, E. C. 2023

    Abstract

    Understanding psychiatric symptoms in Alzheimer`s disease (AD) is crucial for advancing precision medicine and therapeutic strategies. The relationship between AD behavioral symptoms and asymmetry in spatial tau PET patterns is unknown. Braak tau progression implicates the temporal lobes early. However, the clinical and pathological implications of temporal tau laterality remain unexplored. This cross-sectional study investigated the correlation between temporal tau PET asymmetry and behavior assessed using the neuropsychiatric inventory, and composite scores for memory, executive function, and language; using data from the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset. In the entire cohort, continuous right and left temporal tau contributions to behavior and cognition were evaluated controlling for age, sex, education, and tau burden on the contralateral side. Additionally, a temporal tau laterality index was calculated to define "asymmetry-extreme" groups (individuals with laterality indices greater than two standard deviations from the mean). 858 individuals (age=73.9±7.7 years, 434(50%) females) were included, comprising 438 cognitively unimpaired (CU) (53.4%) and 420 impaired (CI) participants (48.9%). In the full cohort analysis, right temporal tau was associated with worse behavior (B(SE)=7.19 (2.9), p-value=0.01) and left temporal tau was associated with worse language (B(SE)=1.4(0.2), p-value<0.0001). Categorization into asymmetry-extreme groups revealed 20 right- and 27 left-asymmetric participants. Within these extreme groups, four patterns of tau PET uptake were observed: anterior temporal, typical AD, typical AD with frontal involvement, and posterior. Asymmetrical tau burden is associated with distinct behavioral and cognitive profiles. Behavioral and socioemotional measures are needed to understand right-sided asymmetry in AD.

    View details for DOI 10.1101/2023.11.10.23296836

    View details for PubMedID 37986964

    View details for PubMedCentralID PMC10659470

  • Application of Machine Learning Driven Computational Approaches for Novel CNS PET Tracer Development Jackson, I., Luo, A., Webb, E., Zhang, B., Guo, A., Nagy, S., Shao, X., Kuo, R., Carlson, M., Alam, I., Rodriguez, A., Winton, W., Stauff, J., Kalita, M., Scott, P., James, M. ELSEVIER SCIENCE INC. 2023: S40-S41
  • Development and Initial Assessment of [18F]OP-801: a Novel Hydroxyl Dendrimer PET Tracer for Preclinical Imaging of Innate Immune Activation in the Whole Body and Brain. Molecular imaging and biology Carlson, M. L., Jackson, I. M., Azevedo, E. C., Reyes, S. T., Alam, I. S., Kellow, R., Castillo, J. B., Nagy, S. C., Sharma, R., Brewer, M., Cleland, J., Shen, B., James, M. L. 2023

    Abstract

    PURPOSE: Innate immune activation plays a critical role in the onset and progression of many diseases. While positron emission tomography (PET) imaging provides a non-invasive means to visualize and quantify such immune responses, most available tracers are not specific for innate immune cells. To address this need, we developed [18F]OP-801 by radiolabeling a novel hydroxyl dendrimer that is selectively taken up by reactive macrophages/microglia and evaluated its ability to detect innate immune activation in mice following lipopolysaccharide (LPS) challenge.PROCEDURES: OP-801 was radiolabeled in two steps: [18F]fluorination of a tosyl precursor to yield [18F]3-fluoropropylazide, followed by a copper-catalyzed click reaction. After purification and stability testing, [18F]OP-801 (150-250 muCi) was intravenously injected into female C57BL/6 mice 24 h after intraperitoneal administration of LPS (10 mg/kg, n=14) or saline (n=6). Upon completing dynamic PET/CT imaging, mice were perfused, and radioactivity was measured in tissues of interest via gamma counting or autoradiography.RESULTS: [18F]OP-801 was produced with >95% radiochemical purity, 12-52 muCi/mug specific activity, and 4.3±1.5% decay-corrected yield. Ex vivo metabolite analysis of plasma samples (n=4) demonstrated high stability in mice (97±3% intact tracer >120 min post-injection). PET/CT images of mice following LPS challenge revealed higher signal in organs known to be inflamed in this context, including the liver, lung, and spleen. Gamma counting confirmed PET findings, showing significantly elevated signal in the same tissues compared to saline-injected mice: the liver (p=0.009), lung (p=0.030), and spleen (p=0.004). Brain PET/CT images (summed 50-60 min) revealed linearly increasing [18F]OP-801 uptake in the whole brain that significantly correlated with murine sepsis score (r=0.85, p<0.0001). Specifically, tracer uptake was significantly higher in the brain stem, cortex, olfactory bulb, white matter, and ventricles of LPS-treated mice compared to saline-treated mice (p<0.05).CONCLUSION: [18F]OP-801 is a promising new PET tracer for sensitive and specific detection of activated macrophages and microglia that warrants further investigation.

    View details for DOI 10.1007/s11307-023-01850-5

    View details for PubMedID 37735280

  • Erratum: "Optimizing the frame duration for data-driven rigid motion estimation in brain PET imaging". Medical physics Spangler-Bickella, M. G., Hurley, S. A., Deller, T. W., Jansen, F., Bettinardi, V., Carlson, M., Zeineh, M., Zaharchuk, G., McMillan, A. B. 2023; 50 (8): 5295

    View details for DOI 10.1002/mp.16595

    View details for PubMedID 37573580

  • Clinical Radiosynthesis and Translation of [18F]OP-801: A Novel Radiotracer for Imaging Reactive Microglia and Macrophages. ACS chemical neuroscience Jackson, I. M., Carlson, M. L., Beinat, C., Malik, N., Kalita, M., Reyes, S., Azevedo, E. C., Nagy, S. C., Alam, I. S., Sharma, R., La Rosa, S. A., Moradi, F., Cleland, J., Shen, B., James, M. L. 2023

    Abstract

    Positron emission tomography (PET) is a powerful tool for studying neuroinflammatory diseases; however, current PET biomarkers of neuroinflammation possess significant limitations. We recently reported a promising dendrimer PET tracer ([18F]OP-801), which is selectively taken up by reactive microglia and macrophages. Here, we describe further important characterization of [18F]OP-801 in addition to optimization and validation of a two-step clinical radiosynthesis. [18F]OP-801 was found to be stable in human plasma for 90 min post incubation, and human dose estimates were calculated for 24 organs of interest; kidneys and urinary bladder wall without bladder voiding were identified as receiving the highest absorbed dose. Following optimization detailed herein, automated radiosynthesis and quality control (QC) analyses of [18F]OP-801 were performed in triplicate in suitable radiochemical yield (6.89 ± 2.23% decay corrected), specific activity (37.49 ± 15.49 GBq/mg), and radiochemical purity for clinical imaging. Importantly, imaging mice with tracer (prepared using optimized methods) 24 h following the intraperitoneal injection of liposaccharide resulted in the robust brain PET signal. Cumulatively, these data enable clinical translation of [18F]OP-801 for imaging reactive microglia and macrophages in humans. Data from three validation runs of the clinical manufacturing and QC were submitted to the Food and Drug Administration (FDA) as part of a Drug Master File (DMF). Subsequent FDA approval to proceed was obtained, and a phase 1/2 clinical trial (NCT05395624) for first-in-human imaging in healthy controls and patients with amyotrophic lateral sclerosis is underway.

    View details for DOI 10.1021/acschemneuro.3c00028

    View details for PubMedID 37310119

  • Development and initial evaluation of a novel 11C-labeled PET tracer to image GPR84 expressing-myeloid cells during neuroinflammation Kalita, M., Park, J., Hayee, S., Marsango, S., Carlson, M., Reyes, S., Nagy, S., Straniero, V., Pandrala, M., Jackson, I., Alam, I., Valoti, E., Milligan, G., Shen, B., James, M. SOC NUCLEAR MEDICINE INC. 2023
  • High-resolution hippocampal diffusion tensor imaging of mesial temporal sclerosis in refractory epilepsy. Epilepsia Chau Loo Kung, G., Chiu, A., Davey, Z., Mouchawar, N., Carlson, M., Moein Taghavi, H., Martin, D., Graber, K., Razavi, B., McNab, J., Zeineh, M. 2022

    Abstract

    OBJECTIVE: We explore the possibility of using diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) to discern microstructural abnormalities in the hippocampus indicative of mesial temporal sclerosis (MTS) at the subfield level.METHODS: We analyzed data from 57 patients with refractory epilepsy who previously underwent 3.0-T magnetic resonance imaging (MRI) including DTI as a standard part of presurgical workup. We collected information about each subject's seizure semiology, conventional electroencephalography (EEG), high-density EEG, positron emission tomography reports, surgical outcome, and available histopathological findings to assign a final diagnostic category. We also reviewed the radiology MRI report to determine the radiographic category. DTI- and NODDI-based metrics were obtained in the hippocampal subfields.RESULTS: By examining diffusion characteristics among subfields in the final diagnostic categories, we found lower orientation dispersion indices and elevated axial diffusivity in the dentate gyrus in MTS compared to no MTS. By similarly examining among subfields in the different radiographic categories, we found all diffusion metrics were abnormal in the dentate gyrus and CA1. We finally examined whether diffusion imaging would better inform a radiographic diagnosis with respect to the final diagnosis, and found that dentate diffusivity suggested subtle changes that may help confirm a positive radiologic diagnosis.SIGNIFICANCE: The results suggest that diffusion metric analysis at the subfield level, especially in dentate gyrus and CA1, maybe useful for clinical confirmation of MTS.

    View details for DOI 10.1111/epi.17330

    View details for PubMedID 35751514

  • Radiosynthesis and initial preclinical evaluation of [11C]AZD1283 as a potential P2Y12R PET radiotracer. Nuclear medicine and biology Jackson, I. M., Buccino, P. J., Azevedo, E. C., Carlson, M. L., Luo, A. S., Deal, E. M., Kalita, M., Reyes, S. T., Shao, X., Beinat, C., Nagy, S. C., Chaney, A. M., Anders, D. A., Scott, P. J., Smith, M., Shen, B., James, M. L. 2022

    Abstract

    INTRO: Chronic neuroinflammation and microglial dysfunction are key features of many neurological diseases, including Alzheimer's Disease and multiple sclerosis. While there is unfortunately a dearth of highly selective molecular imaging biomarkers/probes for studying microglia in vivo, P2Y12R has emerged as an attractive candidate PET biomarker being explored for this purpose. Importantly, P2Y12R is selectively expressed on microglia in the CNS and undergoes dynamic changes in expression according to inflammatory context (e.g., toxic versus beneficial/healing states), thus having the potential to reveal functional information about microglia in living subjects. Herein, we identified a high affinity, small molecule P2Y12R antagonist (AZD1283) to radiolabel and assess as a candidate radiotracer through in vitro assays and in vivo positron emission tomography (PET) imaging of both wild-type and total knockout mice and a non-human primate.METHODS: First, we evaluated the metabolic stability and passive permeability of non-radioactive AZD1283 in vitro. Next, we radiolabeled [11C]AZD1283 with radioactive precursor [11C]NH4CN and determined stability in formulation and human plasma. Finally, we investigated the in vivo stability and kinetics of [11C]AZD1283 via dynamic PET imaging of naive wild-type mice, P2Y12R knockout mouse, and a rhesus macaque.RESULTS: We determined the half-life of AZD1283 in mouse and human liver microsomes to be 37 and>160min, respectively, and predicted passive CNS uptake with a small amount of active efflux, using a Caco-2 assay. Our radiolabeling efforts afforded [11C]AZD1283 in an activity of 12.69±10.64mCi with high chemical and radiochemical purity (>99%) and molar activity of 1142.84±504.73mCi/mumol (average of n=3). Of note, we found [11C]AZD1283 to be highly stable in vitro, with >99% intact tracer present after 90min of incubation in formulation and 60min of incubation in human serum. PET imaging revealed negligible brain signal in healthy wild-type mice (n=3) and a P2Y12 knockout mouse (0.55±0.37%ID/g at 5min post injection). Strikingly, high signal was detected in the liver of all mice within the first 20min of administration (peak uptake=58.28±18.75%ID/g at 5min post injection) and persisted for the remaining duration of the scan. Ex vivo gamma counting of mouse tissues at 60min post-injection mirrored in vivo data with a mean %ID/g of 0.9%±0.40, 0.02%±0.01, and 106±29.70% in the blood, brain, and liver, respectively (n=4). High performance liquid chromatography (HPLC) analysis of murine blood and liver metabolite samples revealed a single radioactive peak (relative area under peak: 100%), representing intact tracer. Finally, PET imaging of a rhesus macaque also revealed negligible CNS uptake/binding in monkey brain (peak uptake=0.37 Standard Uptake Values (SUV)).CONCLUSION: Despite our initial encouraging liver microsome and Caco-2 monolayer data, in addition to the observed high stability of [11C]AZD1283 in formulation and human serum, in vivo brain uptake was negligible and rapid accumulation was observed in the liver of both naive wildtype and P2Y12R knockout mice. Liver signal appeared to be independent of both metabolism and P2Y12R expression due to the confirmation of intact tracer in this tissue for both wildtype and P2Y12R knockout mice. In Rhesus Macaque, negligible uptake of [11C]AZD1283 brain indicates a lack of potential for translation or its further investigation in vivo. P2Y12R is an extremely promising potential PET biomarker, and the data presented here suggests encouraging metabolic stability for this scaffold; however, the mechanism of liver uptake in mice should be elucidated prior to further analogue development.

    View details for DOI 10.1016/j.nucmedbio.2022.05.001

    View details for PubMedID 35680502

  • TRACKING INNATE IMMUNE ACTIVATION IN A MOUSE MODEL OF PARKINSON'S DISEASE USING TREM1 AND TSPO PET TRACERS. Journal of nuclear medicine : official publication, Society of Nuclear Medicine Lucot, K. L., Stevens, M. Y., Bonham, T. A., Azevedo, E. C., Chaney, A. M., Webber, E. D., Jain, P., Klockow, J. L., Jackson, I. M., Carlson, M. L., Graves, E. E., Montine, T. J., James, M. L. 2022

    Abstract

    Parkinson's disease (PD) is associated with aberrant innate immune responses, including microglial activation and infiltration of peripheral myeloid cells into the central nervous system (CNS). Methods to investigate innate immune activation in PD are limited and have not yet elucidated key interactions between neuroinflammation and peripheral inflammation. Translocator protein 18 kDa (TSPO)-positron emission tomography (PET) is a widely evaluated imaging approach for studying activated microglia and peripheral myeloid lineage cells in vivo, however it is yet to be fully explored in PD. Herein we investigate the utility of TSPO-PET, in addition to PET imaging of triggering receptor expressed on myeloid cells 1 (TREM1) - a novel biomarker of proinflammatory myeloid cells - for detecting innate immune responses in the 6-hydroxydopamine (6-OHDA) mouse model of dopaminergic neuron degeneration. Methods: C57/BL6J and TREM1-knockout mice were stereotaxically injected with 6-OHDA in the left striatum; control mice were saline-injected. At day 7 or 14 post-surgery, mice were administered 18F-GE-180, 64Cu-TREM1-mAb or 64Cu-Isotype control-mAb and imaged by PET/CT. Ex vivo autoradiography (ARG) was performed to obtain high resolution images of tracer binding within the brain. Immunohistochemistry was conducted to verify myeloid cell activation and dopaminergic cell death and quantitative PCR and flow cytometry were completed to assess levels of target in the brain. Results: PET/CT images of both tracers showed elevated signal within the striatum of 6-OHDA-injected mice compared to those injected with saline. ARG afforded higher resolution brain images and revealed significant TSPO and TREM1 tracer binding within the ipsilateral striatum of 6-OHDA- compared to saline-injected mice at both 7- and 14-days post-toxin. Interestingly, 18F-GE-180 enabled detection of inflammation in the brain and peripheral tissues (blood and spleen) of 6-OHDA mice, whereas 64Cu-TREM1-mAb appeared to be more sensitive and specific for detecting neuroinflammation, in particular infiltrating myeloid cells, in these mice, as demonstrated by flow cytometry findings and higher tracer binding signal-to-background ratios in brain. Conclusion: TSPO- and TREM1-PET tracers are promising tools for investigating different cell types involved in innate immune activation in the context of dopaminergic neurodegeneration, thus warranting further investigation in other PD rodent models and human postmortem tissue to assess their clinical potential.

    View details for DOI 10.2967/jnumed.121.263039

    View details for PubMedID 35177426

  • Optimizing the Frame Duration for Data-Driven Rigid Motion Estimation in Brain PET Imaging. Medical physics Spangler-Bickell, M. G., Hurley, S. A., Deller, T. W., Jansen, F. n., Bettinardi, V. n., Carlson, M. n., Zeineh, M. n., Zaharchuk, G. n., McMillan, A. B. 2021

    Abstract

    Data-driven rigid motion estimation for PET brain imaging is usually performed using data frames sampled at low temporal resolution to reduce the overall computation time and to provide adequate signal-to-noise ratio in the frames. In recent work it has been demonstrated that list-mode reconstructions of ultra-short frames are sufficient for motion estimation and can be performed very quickly. In this work we take the approach of using image-based registration of reconstructions of very short frames for data-driven motion estimation, and optimize a number of reconstruction and registration parameters (frame duration, MLEM iterations, image pixel size, post-smoothing filter, reference image creation, and registration metric) to ensure accurate registrations while maximizing temporal resolution and minimizing total computation time.Data from 18 F-uorodeoxyglucose (FDG) and 18 F-orbetaben (FBB) tracer studies with varying count rates are analysed, for PET/MR and PET/CT scanners. For framed reconstructions using various parameter combinations inter-frame motion is simulated and image-based registrations are performed to estimate that motion.For FDG and FBB tracers using 4 × 105 true and scattered coincidence events per frame ensures that 95% of the registrations will be accurate to within 1 mm of the ground truth. This corresponds to a frame duration of 0:5 - 1 sec for typical clinical PET activity levels. Using 4 MLEM iterations with no subsets, a transaxial pixel size of 4 mm, a post-smoothing filter with 4-6 mm full-width at half-maximum, and averaging two or more frames to create the reference image provides an optimal set of parameters to produce accurate registrations while keeping the reconstruction and processing time low.It is shown that very short frames (≤ 1 sec) can be used to provide accurate and quick data-driven rigid motion estimates for use in an event-by-event motion corrected reconstruction.

    View details for DOI 10.1002/mp.14889

    View details for PubMedID 33880778

  • Hippocampal subfield imaging and fractional anisotropy show parallel changes in Alzheimer's disease tau progression using simultaneous tau-PET/MRI at 3T. Alzheimer's & dementia (Amsterdam, Netherlands) Carlson, M. L., Toueg, T. N., Khalighi, M. M., Castillo, J., Shen, B., Azevedo, E. C., DiGiacomo, P., Mouchawar, N., Chau, G., Zaharchuk, G., James, M. L., Mormino, E. C., Zeineh, M. M. 2021; 13 (1): e12218

    Abstract

    Introduction: Alzheimer's disease (AD) is the most common form of dementia, characterized primarily by abnormal aggregation of two proteins, tau and amyloid beta. We assessed tau pathology and white matter connectivity changes in subfields of the hippocampus simultaneously in vivo in AD.Methods: Twenty-four subjects were scanned using simultaneous time-of-flight 18F-PI-2620 tau positron emission tomography/3-Tesla magnetic resonance imaging and automated segmentation.Results: We observed extensive tau elevation in the entorhinal/perirhinal regions, intermediate tau elevation in cornu ammonis 1/subiculum, and an absence of tau elevation in the dentate gyrus, relative to controls. Diffusion tensor imaging showed parahippocampal gyral fractional anisotropy was lower in AD and mild cognitive impairment compared to controls and strongly correlated with early tau accumulation in the entorhinal and perirhinal cortices.Discussion: This study demonstrates the potential for quantifiable patterns of 18F-PI2620 binding in hippocampus subfields, accompanied by diffusion and volume metrics, to be valuable markers of AD.

    View details for DOI 10.1002/dad2.12218

    View details for PubMedID 34337132

  • Simultaneous FDG-PET/MRI detects hippocampal subfield metabolic differences in AD/MCI. Scientific reports Carlson, M. L., DiGiacomo, P. S., Fan, A. P., Goubran, M., Khalighi, M. M., Chao, S. Z., Vasanawala, M., Wintermark, M., Mormino, E., Zaharchuk, G., James, M. L., Zeineh, M. M. 2020; 10 (1): 12064

    Abstract

    The medial temporal lobe is one of the most well-studied brain regions affected by Alzheimer's disease (AD). Although the spread of neurofibrillary pathology in the hippocampus throughout the progression of AD has been thoroughly characterized and staged using histology and other imaging techniques, it has not been precisely quantified in vivo at the subfield level using simultaneous positron emission tomography (PET) and magnetic resonance imaging (MRI). Here, we investigate alterations in metabolism and volume using [18F]fluoro-deoxyglucose (FDG) and simultaneous time-of-flight (TOF) PET/MRI with hippocampal subfield analysis of AD, mild cognitive impairment (MCI), and healthy subjects. We found significant structural and metabolic changes within the hippocampus that can be sensitively assessed at the subfield level in a small cohort. While no significant differences were found between groups for whole hippocampal SUVr values (p=0.166), we found a clear delineation in SUVr between groups in the dentate gyrus (p=0.009). Subfield analysis may be more sensitive for detecting pathological changes using PET-MRI in AD compared to global hippocampal assessment.

    View details for DOI 10.1038/s41598-020-69065-0

    View details for PubMedID 32694602

  • Neuroinflammation PET imaging: Current opinion and future directions. Journal of nuclear medicine : official publication, Society of Nuclear Medicine Jain, P., Chaney, A., Carlson, M. L., Jackson, I. M., Rao, A., James, M. L. 2020

    Abstract

    Neuroinflammation is a pathological hallmark of numerous neurologic diseases. Positron emission tomography (PET) imaging enables a non-invasive means to investigate, quantify, and track the spatiotemporal dynamics of various immune cells in living subjects. Translocator protein 18 kDa (TSPO)-PET is a technique for detecting glial activation that has yielded valuable clinical data linking neuroinflammation to cognitive decline in neurodegenerative diseases and has also been used preliminarily as a therapy monitoring tool. However, considerable limitations of TSPO-PET have prompted identification of other more cell-specific and functionally relevant biomarkers. This review analyzes the clinical potential of available and emerging PET biomarkers of innate and adaptive immune responses, with mention of exciting future directions for the field.

    View details for DOI 10.2967/jnumed.119.229443

    View details for PubMedID 32620705

  • A within-coil optical prospective motion-correction system for brain imaging at 7T. Magnetic resonance in medicine DiGiacomo, P. n., Maclaren, J. n., Aksoy, M. n., Tong, E. n., Carlson, M. n., Lanzman, B. n., Hashmi, S. n., Watkins, R. n., Rosenberg, J. n., Burns, B. n., Skloss, T. W., Rettmann, D. n., Rutt, B. n., Bammer, R. n., Zeineh, M. n. 2020

    Abstract

    Motion artifact limits the clinical translation of high-field MR. We present an optical prospective motion correction system for 7 Tesla MRI using a custom-built, within-coil camera to track an optical marker mounted on a subject.The camera was constructed to fit between the transmit-receive coils with direct line of sight to a forehead-mounted marker, improving upon prior mouthpiece work at 7 Tesla MRI. We validated the system by acquiring a 3D-IR-FSPGR on a phantom with deliberate motion applied. The same 3D-IR-FSPGR and a 2D gradient echo were then acquired on 7 volunteers, with/without deliberate motion and with/without motion correction. Three neuroradiologists blindly assessed image quality. In 1 subject, an ultrahigh-resolution 2D gradient echo with 4 averages was acquired with motion correction. Four single-average acquisitions were then acquired serially, with the subject allowed to move between acquisitions. A fifth single-average 2D gradient echo was acquired following subject removal and reentry.In both the phantom and human subjects, deliberate and involuntary motion were well corrected. Despite marked levels of motion, high-quality images were produced without spurious artifacts. The quantitative ratings confirmed significant improvements in image quality in the absence and presence of deliberate motion across both acquisitions (P < .001). The system enabled ultrahigh-resolution visualization of the hippocampus during a long scan and robust alignment of serially acquired scans with interspersed movement.We demonstrate the use of a within-coil camera to perform optical prospective motion correction and ultrahigh-resolution imaging at 7 Tesla MRI. The setup does not require a mouthpiece, which could improve accessibility of motion correction during 7 Tesla MRI exams.

    View details for DOI 10.1002/mrm.28211

    View details for PubMedID 32077521