Byung Chul Yoon, MD, PhD ("Jason") - Stanford Profiles

Byung Chul Yoon, MD, PhD ("Jason")

Assistant Professor of Radiology (Veterans Affairs)

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Academic Appointments

• Assistant Professor - University Medical Line, Radiology

Honors & Awards

• Outstanding Author, Journal of Spine Surgery (2025)
• Recognizing Individuals for Support and Empowerment (RISE) Award, Stanford-HBMC Summer Research Program (2025)
• Early Career Development Program, VA Palo Alto (2024)
• Recognizing Individuals for Support and Empowerment (RISE) Award, REACH-HBMC Summer Research Program (2024)
• PAVIR Bid & Proposal Award, Palo Alto Veterans Institute for Research (2022)
• Thrall Innovation Grant, Department of Radiology, Massachusetts General Hospital (2021)
• ASNR20 Head and Neck Outstanding Presentation Award, American Society of Neuroradiology (2020)
• Alpha Omega Alpha, Stanford (2018)
• Moskowitz Research Award, The Moskowitz Fund; Stanford Radiology (2015)
• Gates Cambridge Scholarship, Bill and Melinda Gates Foundation (2007)
• Overseas Research Scholars Award, Secretary of State for Education and Science, United Kingdom (2007)
• William Welch Award, Johns Hopkins School of Medicine (2007)
• Phi Beta Kappa (junior class induction), Johns Hopkins University (2003)
• Provost's Undergraduate Research Award, Johns Hopkins University (2002)
• Woodrow Wilson Undergraduate Research Fellowship, Johns Hopkins University (2002)

Professional Education

• Fellowship, Massachusetts General Hospital, Neuroradiology (Chief Fellow 2019-2020) (2020)
• Residency, Stanford Heath Care, Diagnostic Radiology (Chief Resident 2017-2018) (2018)
• MD, Johns Hopkins School of Medicine, Medicine (2012)
• PhD, Cambridge University (Trinity College), Physiology, development and neuroscience (2010)
• BA, Johns Hopkins University, Neuroscience (2005)

Contact

• Academic [email protected] University - Faculty Department: Rad/Veterans Affairs Position: Assistant Professor University - Staff Department: Rad/Veterans Affairs Position: Assistant Professor at PAVAHCS

Additional Info

• Mail Code: 5621

Current Research and Scholarly Interests

1. Alzheimer Disease and amyloid-related imaging abnormalities (ARIA)2. Low-intensity focused ultrasound (LIFU)3. Ultrasound imaging

All Publications

• Evaluation of temperature elevation associated with low-intensity focused ultrasound (LIFU) stimulation with or without a deep brain electrode. Brain stimulation Rao, V., Coetzee, J., Perez, L., Penalba, A., Adamson, M., Yoon, B. C. 2025

  View details for DOI 10.1016/j.brs.2025.10.003

  View details for PubMedID 41067685

• Giant calcified lumbar disc herniation in post-operative adjacent segment degeneration: a case report. Journal of spine surgery (Hong Kong) Keyserling, H., Zhang, Y., Skirboll, S., Sobel, R. A., Yoon, B. C. 2025; 11 (3): 757-763

  Abstract

  Giant, calcified disc herniation is a rare type of intervertebral disc calcification and herniation where a large calcified, herniated disc occupies more than 40% of the spinal canal. Cases of giant, calcified disc herniations have been reported primarily in the thoracic spine in adults. They are associated with more symptomatic disc disease and can pose surgical challenges. However, little is known about their occurrence in the lumbar spine, especially in association with prior spine surgeries. The aim of this case report is to describe clinical findings and management of rare, giant, calcified disc herniation presenting as adjacent level degeneration in the lumbar spine.A 75-year-old man with several previous lumbar spine surgeries, including posterior instrumented fusion at L3-S1, presented with a 5-week history of progressive bilateral lower extremity weakness. Lumbar spine magnetic resonance imaging (MRI) and computed tomography (CT) revealed a large, calcified intraspinal mass in the right paracentral region at L2-L3, adjacent to the prior surgical levels. It resulted in severe narrowing of the right lateral recess. This lesion was new when compared to the lumbar spine MRI performed 6 months prior. The lesion was surgically resected without complications, and the pathology revealed a degenerating disc with bone fragments and calcifications.This case demonstrates an unusual presentation of a giant, calcified disc herniation in the lumbar spine as a component of adjacent segment degeneration in a patient with prior lumbar spine surgeries. The case illustrates the dynamic nature of intervertebral disc herniations and calcifications as well as management considerations.

  View details for DOI 10.21037/jss-25-29

  View details for PubMedID 41089927

  View details for PubMedCentralID PMC12516573

• Toward Foundational Model for Sleep Analysis Using a Multimodal Hybrid-Self-Supervised Learning Framework. IEEE transactions on cybernetics Lee, C. H., Kim, H., Yoon, B. C., Kim, D. J. 2025; PP

  Abstract

  Sleep is essential for maintaining human health and quality of life. Analyzing physiological signals during sleep is critical in assessing sleep quality and diagnosing sleep disorders. However, manual diagnoses by clinicians are time-intensive and subjective. Despite advances in deep learning that have enhanced automation, these approaches remain heavily dependent on large-scale labeled datasets. This study introduces SynthSleepNet, a multimodal hybrid-self-supervised learning (SSL) framework designed for analyzing polysomnography (PSG) data. SynthSleepNet effectively integrates masked prediction and contrastive learning to leverage complementary features across multiple modalities, including electroencephalogram (EEG), electrooculography (EOG), electromyography (EMG), and electrocardiogram (ECG). This approach enables the model to learn highly expressive representations of PSG data. Furthermore, a TCM based on Mamba was developed to efficiently capture contextual information across signals. SynthSleepNet achieved superior performance compared to state-of-the-art methods across three downstream tasks: sleep-stage classification, apnea detection, and hypopnea detection, with accuracies of 89.89%, 99.75%, and 89.60%, respectively. The model demonstrated robust performance in a semi-SSL environment with limited labels, achieving accuracies of 87.98%, 99.37%, and 77.52% in the same tasks. These results underscore the potential of the model as a foundational tool for the comprehensive analysis of PSG data. SynthSleepNet demonstrates comprehensively superior performance across multiple downstream tasks compared to other methodologies, making it expected to set a new standard for sleep disorder monitoring and diagnostic systems. The source code is available at https://github.com/dlcjfgmlnasa/SynthSleepNet.

  View details for DOI 10.1109/TCYB.2025.3603608

  View details for PubMedID 40924530

• Improving real-time ultrasound spine imaging with a large-aperture array. Science advances Lu, N., Foiret, J., Guo, Y., Yoon, B. C., Ferrara, K. W. 2025; 11 (30): eadw2601

  Abstract

  Ultrasound offers a safe, low-cost alternative to computed tomography (CT) and magnetic resonance imaging for spinal diagnostics and intervention by enabling real-time imaging. However, the complex structure of the spine and acoustic shadowing from bones present challenges for ultrasonography. This study addresses these limitations using an 8.8-centimeter 384-element large-aperture array and full aperture-based imaging protocols. Volumetric scanning across multiple vertebrae was accomplished in 5 seconds using ultrafast, diverging wave acquisition. In seven healthy volunteers, the large-aperture array and diverging wave transmission improved resolution, contrast, and visualization of the spinal canal, venous plexuses, and facet joints compared with conventional probes. A comparison between the coregistered CT and ultrasound scan confirmed the imaging accuracy. A simulated lumbar puncture demonstrated needle tip visualization throughout the trajectory into the spinal canal. The results suggest that large-aperture arrays, coupled with diverging wave imaging sequences, are a valuable tool for spine imaging and image-guided intervention.

  View details for DOI 10.1126/sciadv.adw2601

  View details for PubMedID 40712026

• Sex differences in structural and functional connectivity in healthy young adults from the Amsterdam Open MRI Collection. Brain structure & function Kang, X., Adamson, M. M., Yoon, B. C. 2025; 230 (6): 98

  Abstract

  Understanding the structural and functional differences in the brain between sexes may provide insight into the sex differences in behaviors, cognition, and disorders. Structural (SC) and functional (FC) connectivity were examined in this study on 111 (Females = 56) right-handed, healthy, young adults controlled for brain size, using the cluster and region-of-interest (ROI) based algorithms. A nearly moderate correlation between SC and FC was observed for both male and female cohorts, but the degree of correlation was not significantly different between the sexes. Sex differences in SC were found in both intra- and inter-hemispheric clusters and connections, with more differences in the left hemisphere. Compared to males, females were found to have anatomical parcels with higher SC in the left hemisphere involving the language network. Females were also found to have anatomical parcels with higher FC than males in the left hemisphere, including connections to the somatomotor and default mode networks, and lower FC distributed symmetrically between the two hemispheres. These findings highlight the sex differences in the brain structure and function in healthy, young adult populations that may underly behavioral and cognitive differences, including language processing and somatomotor perception.

  View details for DOI 10.1007/s00429-025-02965-x

  View details for PubMedID 40522500

  View details for PubMedCentralID 10043182

• Corrigendum to "Low-intensity focused ultrasound (LIFU) for the treatment of post-traumatic headache (PTH) in veterans: A feasibility study" [Brain Stimulation: Basic, Translational, and Clinical Research in Neuromodulation, vol. 17 (2024), pg. 1290-1292/No. 6]. Brain stimulation Yoon, B. C., Coetzee, J. P., Kang, X., Brar, R., Timmerman, M., Harris, O., Madrigal, E., Adamson, M. M. 2025; 18 (2): 211

  View details for DOI 10.1016/j.brs.2025.01.019

  View details for PubMedID 39965459

• Relationship Between Structural and Functional Network Connectivity Changes for Patients With Traumatic Brain Injury and Chronic Health Symptoms. The European journal of neuroscience Kang, X., Grossner, E., Yoon, B. C., Adamson, M. M. 2025; 61 (2): e16678

  Abstract

  Combination of structural and functional brain connectivity methods provides a more complete and effective avenue into the investigation of cortical network responses to traumatic brain injury (TBI) and subtle alterations in brain connectivity associated with TBI. Structural connectivity (SC) can be measured using diffusion tensor imaging to evaluate white matter integrity, whereas functional connectivity (FC) can be studied by examining functional correlations within or between functional networks. In this study, the alterations of SC and FC were assessed for TBI patients, with and without chronic symptoms (TBIcs/TBIncs), compared with a healthy control group (CG). The correlation between global SC and FC was significantly increased for both TBI groups compared with CG. SC was significantly lower in the TBIcs group compared with CG, and FC changes were seen in the TBIncs group compared with CG. When comparing TBI groups, FC differences were observed in the TBIcs group compared with the TBIncs group. These observations show that the presence of chronic symptoms is associated with a distinct pattern of SC and FC changes including the atrophy of the SC and a mixture of functional hypoconnectivity and hyperconnectivity, as well as loss of segregation of functional networks.

  View details for DOI 10.1111/ejn.16678

  View details for PubMedID 39831462

• Toward Foundational Model for Sleep Analysis Using a Multimodal Hybrid Self-Supervised Learning Framework arXiv Lee, C., Kim, H., Yoon, B. C., Kim, D. 2025
• Low-intensity focused ultrasound (LIFU) for the treatment of post-traumatic headache (PTH) in veterans: a feasibility study. Brain stimulation Yoon, B. C., Coetzee, J. P., Kang, X., Brar, R., Timmerman, M., Harris, O., Madrigal, E., Adamson, M. M. 2024

  View details for DOI 10.1016/j.brs.2024.11.007

  View details for PubMedID 39566597

• Characteristics of the Structural Connectivity in Patients with Brain Injury and Chronic Health Symptoms: A Pilot Study. Neuroinformatics Kang, X., Yoon, B. C., Grossner, E., Adamson, M. M. 2024

  Abstract

  Diffusion properties from diffusion tensor imaging (DTI) are exquisitely sensitive to white matter abnormalities incurred during traumatic brain injury (TBI), especially for those patients with chronic post-TBI symptoms such as headaches, dizziness, fatigue, etc. The evaluation of structural and functional connectivity using DTI has become a promising method for identifying subtle alterations in brain connectivity associated with TBI that are otherwise not visible with conventional imaging. This study assessed whether TBI patients with (n = 17) or without (n = 16) chronic symptoms (TBIcs/TBIncs) exhibit any changes in structural connectivity (SC) and mean fractional anisotropy (mFA) of intra- and inter-hemispheric connections when compared to a control group (CG) (n = 13). Reductions in SC and mFA were observed for TBIcs compared to CG, but not for TBIncs. More connections were found to have mFA reductions than SC reductions. On the whole, SC is dominated by ipsilateral connections for all the groups after the comparison of contralateral and ipsilateral connections. More contra-ipsi reductions of mFA were found for TBIcs than TBIncs compared to CG. These findings suggest that TBI patients with chronic symptoms not only demonstrate decreased global and regional mFA but also reduced structural network connectivity.

  View details for DOI 10.1007/s12021-024-09681-7

  View details for PubMedID 38990502

  View details for PubMedCentralID 9592834

• Implicit screening of abdominal aortic aneurysms among veterans using lumbar spine MRI. Current problems in diagnostic radiology Mashhood, A., Malik, S., Yoon, B. C. 2024

  Abstract

  BACKGROUND: Early detection of abdominal aortic aneurysms (AAAs) is critical given the high morbidity and mortality of a ruptured aneurysm. Screening ultrasound is recommended for men 65 and 75 years of age with a smoking history. However, studies have shown that the rate of ultrasound screening is low and that implicit AAA screening by abdominal imaging studies that were not originally intended for AAA screening can play a major role in AAA detection.OBJECTIVE: The main objective was to evaluate the role of lumbar spine MRIs as an implicit AAA screening study by assessing the detection rate of AAAs in a broader cohort of veterans that included screening and non-screening populations.METHODS: 4085 consecutive lumbar spine MRIs from our institution between 2/2020 and 9/2023 were retrospectively reviewed. Each study was labeled AAA present, AAA not present, or indeterminate by radiologists. The correlation between the presence of AAAs and cardiovascular risk factors was assessed using multinomial logistic regression.RESULTS: AAAs were present in 89 studies (2.2%) from 80 patients (mean age 75.8 (56-93), M:F 10:0) and absent in 3935 cases (96.3%) from 3310 patients (mean age 61.7 (19-100), M:F 9:1). Indeterminate cases (n=61, 1.5%) were mainly due to incomplete visualization (70.5%). Mean AAA size was 3.6cm with most AAAs (n=43) smaller than 3.5cm. Sixteen AAAs were 3.5-3.9cm, 16 between 4 and 4.9cm, and 6 between 5 and 5.9cm. Artifact precluded measurements in 8 cases. Among the AAA-positive cases, 20 had no prior documentation of AAA. Twenty-one patients with AAAs would not have met the criteria for the routine AAA screening ultrasound. Higher rates of hypertension, hyperlipidemia, and smoking were observed for the AAA cohort at 78.8% (OR 2.037, CI 1.160-3.576, P=.013), 82.5% (2.808, 1.543-5.110, Pa to be aware of the relatively high frequency of paraspinal myositis in this small cohort of patients with COVID-19 infection.

  View details for DOI 10.3174/ajnr.A6711

  View details for PubMedID 32763902

  View details for PubMedCentralID PMC7661075

• Clinical and Neuroimaging Correlation in Patients with COVID-19. AJNR. American journal of neuroradiology Yoon, B. C., Buch, K., Lang, M., Applewhite, B. P., Li, M. D., Mehan, W. A., Leslie-Mazwi, T. M., Rincon, S. P. 2020; 41 (10): 1791-1796

  Abstract

  Coronavirus disease 2019 (COVID-19) is increasingly being recognized for its multiorgan involvement, including various neurological manifestations. We examined the frequency of acute intracranial abnormalities seen on CT and/or MR imaging in patients with COVID-19 and investigated possible associations between these findings and clinical parameters, including length of hospital stay, requirement for intubation, and development of acute kidney injury.This was a retrospective study performed at a large academic hospital in the United States. A total of 641 patients presented to our institution between March 3, 2020, and May 6, 2020, for treatment of coronavirus disease 2019, of whom, 150 underwent CT and/or MR imaging of the brain. CT and/or MR imaging examinations were evaluated for the presence of hemorrhage, infarction, and leukoencephalopathy. The frequency of these findings was correlated with clinical variables, including body mass index, length of hospital stay, requirement for intubation, and development of acute kidney injury as documented in the electronic medical record.Of the 150 patients, 26 (17%) had abnormal CT and/or MR imaging findings, with hemorrhage in 11 of the patients (42%), infarction in 13 of the patients (50%), and leukoencephalopathy in 7 of the patients (27%). Significant associations were seen between abnormal CT/MR imaging findings and intensive care unit admission (P = .039), intubation (P = .004), and acute kidney injury (P = .030).A spectrum of acute neuroimaging abnormalities was seen in our cohort of patients with coronavirus disease 2019, including hemorrhage, infarction, and leukoencephalopathy. Significant associations between abnormal neuroimaging studies and markers of disease severity (intensive care unit admission, intubation, and acute kidney injury) suggest that patients with severe forms of coronavirus disease 2019 may have higher rates of neuroimaging abnormalities.

  View details for DOI 10.3174/ajnr.A6717

  View details for PubMedID 32912875

  View details for PubMedCentralID PMC7661080

• Comparison of Intraoperative Sonography and Histopathologic Evaluation of Tumor Thickness and Depth of Invasion in Oral Tongue Cancer: A Pilot Study. AJNR. American journal of neuroradiology Yoon, B. C., Bulbul, M. D., Sadow, P. M., Faquin, W. C., Curtin, H. D., Varvares, M. A., Juliano, A. F. 2020; 41 (7): 1245-1250

  Abstract

  For primary squamous cell carcinoma of the oral tongue, accurate assessment of tumor thickness and depth of invasion is critical for staging and operative management. Currently, typical imaging modalities used for preoperative staging are CT and MR imaging. Intraoperatively, CT or MR imaging cannot provide real-time guidance, and assessment by manual palpation is limited in precision. We investigated whether intraoperative sonography is a feasible technique for assessment of tumor thickness and depth of invasion and validated its accuracy by comparing it with histopathologic evaluation of the resected specimen.Twenty-six patients with squamous cell carcinoma of the oral tongue who underwent tumor resection by a single surgeon between March 31, 2016, and April 26, 2019, were prospectively identified. Intraoperative sonography was obtained in planes longitudinal and transverse to the long axis of the tumor. Twenty-two patients had archived images that allowed measurements of tumor thickness and depth of invasion sonographically. Two patients had dysplasia and were excluded. The remaining 20 patients had histologic tumor thickness and histologic depth of invasion measured by a single pathologist.The mean sonographic tumor thickness was 7.5  ± 3.5 mm, and the mean histologic tumor thickness was 7.0  ± 4.2 mm. Mean sonographic depth of invasion and histologic depth of invasion were 6.6  ± 3.4  and 6.4 ± 4.4 mm, respectively. There was excellent correlation between sonographic and histologic measurements for both tumor thickness and depth of invasion with Pearson correlation coefficients of 0.95 (95% CI, 0.87-0.98) and 0.95 (95% CI, 0.87-0.98), respectively.Intraoperative sonography can provide reliable, real-time assessment of the extent of tongue tumors.

  View details for DOI 10.3174/ajnr.A6625

  View details for PubMedID 32554422

  View details for PubMedCentralID PMC7357662

• Preoperative assessment of tumor thickness for oral tongue squamous cell carcinoma using computed tomography. 2020 American Society of Head and Neck Radiology Yoon, B. C., Buch, K., Cunnane, M. E., Sadow, P. M., Varvares, M. A. 2020
• Polymeric perfluorocarbon nanoemulsions are ultrasound-activated wireless drug infusion catheters. Biomaterials Zhong, Q., Yoon, B. C., Aryal, M., Wang, J. B., Ilovitsh, T., Baikoghli, M. A., Hosseini-Nassab, N., Karthik, A., Cheng, R. H., Ferrara, K. W., Airan, R. D. 2019; 206: 73–86

  Abstract

  Catheter-based intra-arterial drug therapies have proven effective for a range of oncologic, neurologic, and cardiovascular applications. However, these procedures are limited by their invasiveness and relatively broad drug spatial distribution. The ideal technique for local pharmacotherapy would be noninvasive and would flexibly deliver a given drug to any region of the body with high spatial and temporal precision. Combining polymeric perfluorocarbon nanoemulsions with existent clinical focused ultrasound systems could in principle meet these needs, but it has not been clear whether these nanoparticles could provide the necessary drug loading, stability, and generalizability across a range of drugs, beyond a few niche applications. Here, we develop polymeric perfluorocarbon nanoemulsions into a generalized platform for ultrasound-targeted delivery of hydrophobic drugs with high potential for clinical translation. We demonstrate that a wide variety of drugs may be effectively uncaged with ultrasound using these nanoparticles, with drug loading increasing with hydrophobicity. We also set the stage for clinical translation by delineating production protocols that are scalable and yield sterile, stable, and optimized ultrasound-activated drug-loaded nanoemulsions. Finally, we exhibit a new potential application of these nanoemulsions for local control of vascular tone. This work establishes the power of polymeric perfluorocarbon nanoemulsions as a clinically-translatable platform for efficacious, noninvasive, and localized ultrasonic drug uncaging for myriad targets in the brain and body.

  View details for PubMedID 30953907

• Suppression of in vivo flow artifacts in power Doppler through spatial and angular coherence beamforming Dahl, J. J., Yoon, B. C., Durot, I., Ducey-Wysling, J., D'Hondt, A., Patek, B., Rubesova, E., Jakovljevic, M., Li, Y. 2019

  View details for DOI 10.1121/1.5137063

• Tracking blood flow changes in the brains of neonates using angular-coherence-based power Doppler Jakovljevic, M., Yoon, B., Abou-Elkacem, L., Rubesova, E., Dahl, J., Byram, B. C., Ruiter, N. V. 2019
• Evaluation of Thick-Slab Overlapping MIP Images of Contrast-Enhanced 3D T1-Weighted CUBE for Detection of Intracranial Metastases: A Pilot Study for Comparison of Lesion Detection, Interpretation Time, and Sensitivity with Nonoverlapping CUBE MIP, CUBE, and Inversion-Recovery-Prepared Fast-Spoiled Gradient Recalled Brain Volume. AJNR. American journal of neuroradiology Yoon, B. C., Saad, A. F., Rezaii, P., Wintermark, M., Zaharchuk, G., Iv, M. 2018

  Abstract

  Early and accurate identification of cerebral metastases is important for prognostication and treatment planning although this process is often time consuming and labor intensive, especially with the hundreds of images associated with 3D volumetric imaging. This study aimed to evaluate the benefits of thick-slab overlapping MIPs constructed from contrast-enhanced T1-weighted CUBE (overlapping CUBE MIP) for the detection of brain metastases in comparison with traditional CUBE and inversion-recovery prepared fast-spoiled gradient recalled brain volume (IR-FSPGR-BRAVO) and nonoverlapping CUBE MIP.A retrospective review of 48 patients with cerebral metastases was performed at our institution from June 2016 to October 2017. Brain MRIs, which were acquired on multiple 3T scanners, included gadolinium-enhanced T1-weighted IR-FSPGR-BRAVO and CUBE, with subsequent generation of nonoverlapping CUBE MIP and overlapping CUBE MIP. Two blinded radiologists identified the total number and location of metastases on each image type. The Cohen κ was used to determine interrater agreement. Sensitivity, interpretation time, and lesion contrast-to-noise ratio were assessed.Interrater agreement for identification of metastases was fair-to-moderate for all image types (κ = 0.222-0.598). The total number of metastases identified was not significantly different across the image types. Interpretation time for CUBE MIPs was significantly shorter than for CUBE and IR-FSPGR-BRAVO, saving at least 50 seconds per case on average (P < .001). The mean lesion contrast-to-noise ratio for both CUBE MIPs was higher than for IR-FSPGR-BRAVO. The mean contrast-to-noise ratio for small lesions (