Clinical Scholar, Radiology
Honors & Awards
Conference Travel Award, Department of Radiology, Duke University (04/2017)
Medical Student Research Grant, RSNA (08/1/16-08/1/17)
Boards, Advisory Committees, Professional Organizations
Member, American Society for Neuroradiology (ASNR) (2016 - Present)
Member, International Society for Magnetic Resonance in Medicine (ISMRM) (2016 - Present)
Member, Radiological Society of North America (RSNA) (2016 - Present)
Residency: Stanford University Radiology Residency (2023) CA
Internship: Harbor UCLA Transitional Year (2019) CA
Medical Education: Duke University School of Medicine (2018) NC
Internship, Harbor-UCLA Medical Center (2019)
M.D., Duke University School of Medicine (2018)
M.S., Tufts University School of Medicine, Biomedical Sciences (2013)
B.S., University of California, Los Angeles, Neuroscience (2011)
Longitudinal alteration of cortical thickness and volume in high-impact sports.
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
- Longitudinal Changes in Hippocampal Subfield Volume Associated with Collegiate Football JOURNAL OF NEUROTRAUMA 2019
- Lateral impacts correlate with falx cerebri displacement and corpus callosum trauma in sports-related concussions BIOMECHANICS AND MODELING IN MECHANOBIOLOGY 2019; 18 (3): 631–49
MR susceptibility contrast imaging using a 2D simultaneous multi-slice gradient-echo sequence at 7T.
2019; 14 (7): e0219705
PURPOSE: To develop a 7T simultaneous multi-slice (SMS) 2D gradient-echo sequence for susceptibility contrast imaging, and to compare its quality to 3D imaging.METHODS: A frequency modulated and phase cycled RF pulse was designed to simultaneously excite multiple slices in multi-echo 2D gradient-echo imaging. The imaging parameters were chosen to generate images with susceptibility contrast, including T2*-weighted magnitude/phase images, susceptibility-weighted images and quantitative susceptibility/R2* maps. To compare their image quality with 3D gradient-echo imaging, both 2D and 3D imaging were performed on 11 healthy volunteers and 4 patients with multiple sclerosis (MS). The signal to noise ratio (SNR) in gray and white matter and their contrast to noise ratio (CNR) was simulated for the 2D and 3D magnitude images using parameters from the imaging. The experimental SNRs and CNRs were measured in gray/white matter and deep gray matter structures on magnitude, phase, R2* and QSM images from volunteers and the visibility of MS lesions on these images from patients was visually rated. All SNRs and CNRs were compared between the 2D and 3D imaging using a paired t-test.RESULTS: Although the 3D magnitude images still had significantly higher SNRs (by 13.0~17.6%), the 2D magnitude and QSM images generated significantly higher gray/white matter or globus pallidus/putamen contrast (by 13.3~87.5%) and significantly higher MS lesion contrast (by 5.9~17.3%).CONCLUSION: 2D SMS gradient-echo imaging can serve as an alternative to often used 3D imaging to obtain susceptibility-contrast-weighted images, with an advantage of providing better image contrast and MS lesion sensitivity.
View details for DOI 10.1371/journal.pone.0219705
View details for PubMedID 31314813
CT Fluoroscopy-Guided Interlaminar Epidural Steroid Injections in the Cervical Spine: Rate of Nontarget Injection Into the Retrodural Space of Okada.
AJR. American journal of roentgenology
2018; 211 (2): 426-431
The purpose of this study was to assess the rate of inadvertent injection into the retrodural space of Okada during CT fluoroscopy-guided interlaminar epidural steroid injection in the cervical spine.Images from cases of cervical interlaminar epidural steroid injection under CT fluoroscopic guidance performed at a single institution between November 2009 and November 2015 were obtained and reviewed. For all cases, the following information was recorded: presence or absence of contrast material within the Okada space, cervical anatomic level at which the procedure was performed, laterality of approach, trainee presence, and years of proceduralist experience. Two-tailed chi-square tests were used to assess categoric variables, and t tests were performed to assess for continuous variables predictive of nontarget injection.A total of 974 CT fluoroscopy-guided cervical interlaminar epidural steroid injections were identified in 728 patients. The presence of contrast material in the retrodural space of Okada was identified in 2.9% of cases (28/974). All cases of inadvertent injection were identified and corrected intraprocedurally. The greatest rate of inadvertent injection (4.6% [18/389]) occurred at C5-6. No variables predictive of inadvertent injection into the Okada space were identified. There was a 0.4% (4/974) complication rate, and all complications were minor.We identified a 2.9% rate of unintended injection into the retrodural space of Okada during cervical interlaminar epidural steroid injection. If unrecognized, these nontarget injections can result in treatment failure in a subset of patients who undergo cervical interlaminar epidural steroid injection. Future study is warranted to assess the rate of inadvertent Okada injection under conventional fluoroscopy and to compare the rates of detection between the two imaging-guided modalities.
View details for DOI 10.2214/AJR.18.19606
View details for PubMedID 29812982
Incidence of Inadvertent Dural Puncture During CT Fluoroscopy-Guided Interlaminar Epidural Corticosteroid Injections in the Cervical Spine: An Analysis of 974 Cases.
AJR. American journal of roentgenology
2017; 209 (3): 656-661
The objective of this study is to determine the rate of inadvertent dural puncture during CT fluoroscopy-guided cervical interlaminar epidural corticosteroid injection. In addition, in a subanalysis, we aim to assess the rate of inadvertent dural puncture superior to C5-C6 occurring during interlaminar epidural corticosteroid injection using CT fluoroscopy guidance because such injections are not performed using conventional fluoroscopy.Images obtained from consecutive CT fluoroscopy-guided cervical interlaminar epidural corticosteroid injections conducted from November 2009 to November 2015 were reviewed. The following information was recorded: the presence of inadvertent dural puncture, the level of the cervical interlaminar space, approach laterality (left or right), anteroposterior spinal canal diameter, and the presence of a trainee. Two-tailed Fisher exact tests were used for assessment of categoric variables, and t tests were used for continuous variables.A total of 974 cervical interlaminar epidural corticosteroid injections were identified in 728 patients. Inadvertent dural punctures were identified in association with 1.4% (14/974) of these injections; all punctures were recognized during the procedure. Needle placements were performed at every cervical level (C1-C2 through C7-T1). The highest rate of dural puncture (2.8%) occurred at C5-C6. No dural punctures occurred superior to C5-C6 (16.6% of cases). The complication rate was 0.4%. Only greater anteroposterior spinal canal diameter was associated with increased dural puncture rates (p = 0.049).CT fluoroscopy-guided cervical interlaminar epidural corticosteroid injections were performed at all levels throughout the cervical spine. A very low complication rate and a minimal rate of inadvertent dural puncture were noted, similar to previously reported rates for conventional fluoroscopy-guided injections limited to the lower cervical spine only.
View details for DOI 10.2214/AJR.16.17738
View details for PubMedID 28657847
Plasticity of binocularity and visual acuity are differentially limited by nogo receptor.
The Journal of neuroscience : the official journal of the Society for Neuroscience
2014; 34 (35): 11631-40
The closure of developmental critical periods consolidates neural circuitry but also limits recovery from early abnormal sensory experience. Degrading vision by one eye throughout a critical period both perturbs ocular dominance (OD) in primary visual cortex and impairs visual acuity permanently. Yet understanding how binocularity and visual acuity interrelate has proven elusive. Here we demonstrate the plasticity of binocularity and acuity are separable and differentially regulated by the neuronal nogo receptor 1 (NgR1). Mice lacking NgR1 display developmental OD plasticity as adults and their visual acuity spontaneously improves after prolonged monocular deprivation. Restricting deletion of NgR1 to either cortical interneurons or a subclass of parvalbumin (PV)-positive interneurons alters intralaminar synaptic connectivity in visual cortex and prevents closure of the critical period for OD plasticity. However, loss of NgR1 in PV neurons does not rescue deficits in acuity induced by chronic visual deprivation. Thus, NgR1 functions with PV interneurons to limit plasticity of binocularity, but its expression is required more extensively within brain circuitry to limit improvement of visual acuity following chronic deprivation.
View details for DOI 10.1523/JNEUROSCI.0545-14.2014
View details for PubMedID 25164659
View details for PubMedCentralID PMC4145169
mTOR Inhibition ameliorates cognitive and affective deficits caused by Disc1 knockdown in adult-born dentate granule neurons.
2013; 77 (4): 647-54
Abnormalities during brain development are thought to cause psychiatric illness and other neurodevelopmental disorders. However, developmental processes such as neurogenesis continue in restricted brain regions of adults, and disruptions of these processes could contribute to the phenotypes of neurodevelopmental disorders. As previously reported, we show that Disc1 knockdown specifically in adult-born dentate gyrus (DG) neurons results in increased mTOR signaling, hyperexcitability, and neuronal structure deficits. Disc1 knockdown also resulted in pronounced cognitive and affective deficits, which could be reversed when the affected DG neurons were inactivated. Importantly, reversing increases in mTOR signaling with an FDA-approved inhibitor both prevented and treated these behavioral deficits, even when associated structural deficits were not reversed. Our findings suggest that a component of the affective and cognitive phenotypes in neurodevelopmental disorders may be caused by disruptions in adult-born neurons. Consequently, treatments directed at this cell population may have a significant impact on these phenotypes.
View details for DOI 10.1016/j.neuron.2012.12.033
View details for PubMedID 23439118
View details for PubMedCentralID PMC3586374
THE EFFICACY OF MESENCHYMAL STEM CELLS IN THORACO-LUMBAR SPINE FUSION SURGERY FOR TRAUMA: A RETROSPECTIVE REVIEW OF OPERATED CASES
MARY ANN LIEBERT INC. 2011: A25
View details for Web of Science ID 000292457600091
The hippocampus plays a selective role in the retrieval of detailed contextual memories.
Current biology : CB
2010; 20 (15): 1336-44
It is widely believed that the hippocampus plays a temporary role in the retrieval of episodic and contextual memories. Initial research indicated that damage to this structure produced amnesia for newly acquired memories but did not affect those formed in the distant past. A number of recent studies, however, have found that the hippocampus is required for the retrieval of episodic and contextual memories regardless of their age. These findings are currently the subject of intense debate, and a satisfying resolution has yet to be identified.The current experiments address this issue by demonstrating that detailed memories require the hippocampus, whereas memories that lose precision become independent of this structure. First, we show that the dorsal hippocampus is preferentially activated by the retrieval of detailed contextual fear memories. We then establish that the hippocampus is necessary for the retrieval of detailed memories by using a context-generalization procedure. Mice that exhibit high levels of generalization to a novel environment show no memory loss when the hippocampus is subsequently inactivated. In contrast, mice that discriminate between contexts are significantly impaired by hippocampus inactivation.Our data suggest that detailed contextual memories require the hippocampus, whereas memories that lose precision can be retrieved without this structure. These findings can account for discrepancies in the literature-memories of our distant past can be either lost or retained after hippocampus damage depending on their quality-and provide a new framework for understanding memory consolidation.
View details for DOI 10.1016/j.cub.2010.06.068
View details for PubMedID 20637623
View details for PubMedCentralID PMC2928141