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Radiology & Imaging
Adult Orthopaedics

Radiology & Imaging



Hollis G. Potter, MD

Visit the Department Page for the full faculty listing.

During the year 2021, the Department of Radiology and Imaging transitioned from its post COVID recovery, with an overreaching mission to address unmet clinical needs through innovative imaging solutions. Our translational research program continues to expand, and we have new clinical offerings from our Interventional Radiology Department to further treat patients with chronic disabling low back and extremity discomfort.

Recent Achievements

Due to the continuing extraordinary generosity of Chase and Stephanie Coleman, we have recently instituted a competitive scholarship award granted to individuals engaged in an HSS laboratory using imaging as outcome measures, to fund either MD or PhD programs. The first two recipients of this award were Sophie Queler, who will be attending Downstate Medical School for her submission entitled “Investigation of Ferumoxytol-Enhanced Magnetic Resonance Neurography for the Detection of Peripheral Nerve Inflammation,” and Erin Argentieri, who will be attending a bioengineering program for her submission entitled “ACL T2* relaxometry in females with unilateral ACL-injury: Associations with laxity, injury risk, hormonal contraceptive use, and mechanical properties.” This is the first scholarship award of its kind at HSS.

In 2021 we implemented a radiation dose monitoring system, which automatically captures a patient’s radiation dose from CT, fluoroscopy (C-arm) and diagnostic x-ray. This new system allows us to evaluate dose outliers and variations in performance as well as to review protocols and prepare us for future initiatives in dose documentation requirements.

Artificial intelligence has enabled more efficient and higher resolution MR imaging, and these algorithms are installed on several of our existing GE units as well as our new Siemens 3T MR unit. These techniques permit high-resolution scanning with markedly reduced acquisition times.


In the 2020-2021 fellowship year, we continued to add to an already robust curriculum, with highlights such as a new surgical techniques conference, an MRI protocol conference, as well as an oncology rotation with Memorial Sloan Kettering Cancer Center, in which our HSS fellows will rotate for two weeks at MSK to review oncology cases. In our Bone Club, the fellows will continue to present at a bimonthly New York City conference with the recent additions of outside institutions including Mass General Hospital and the University of Michigan. We matched four out of four candidates from the top 10 of our rank list, including our number-one candidate.


The HSS MRI Lab received a multi-year Industry Grant Award from Siemens Healthineers for the “Development of Technology to Extend the Scope of MRI in Orthopedics” and hired four new research assistants, sponsored by various grant mechanisms.

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Multiple severe intrinsic constriction of the suprascapular nerve in a patient with Parsonage-Turner syndrome

Darryl Sneag, MD, the current Director of MR Neurography, was also appointed Director of MRI Research and continued his NIH-sponsored R21 award to investigate imaging and serologic biomarkers for detection and monitoring of Parsonage-Turner syndrome (PTS) (neuralgic amyotrophy). Intrinsic constrictions of affected nerves in PTS appear to be a specific marker of the syndrome.

The intramural 2021 Kellen Scholar Grant was awarded to Dr. Sneag and Ek Tsoon Tan, PhD, a scientist in the MRI lab, for “Detection of Wallerian Degeneration by Ferumoxytol-Enhanced MRI.” This is a pilot project that aims to detect early nerve regeneration via contrast-enhanced MRI. Drs. Sneag and Tan, in collaboration with HSS spine surgeon Darren Lebl, MD, from the HSS Spine Service, were also awarded a research grant from Medtronic Navigation Inc. on “3D MRI for Intra-Operative Spine Surgery Guidance.” Drs. Tan and Sneag were awarded a grant from the HSS Innovation Institute to develop conformal cervical spine and brachial plexus radiofrequency MRI coil to improve image quality in these regions. They also continue to collaborate with Simone Winkler, PhD, an electrical engineer at Cornell, to develop ultra-flexible MR coils using novel liquid-metal coil technology.

Drs. Sneag and Tan mentored Simon Sun, MD, a 2020-2021 musculoskeletal imaging fellow, on the project, “Evaluation of Deep-Learning Reconstructed High-Resolution 3D Lumbar Spine MRI to Improve Image Quality,” which was awarded the Charles L. Christian Award for Excellence in Musculoskeletal Research at HSS.

Dr. Sneag also mentored HSS radiologist Philip Colucci, MD, who received an RSNA Research and Education Foundation Fellow Grant to develop an ultra-high-resolution interactive brachial plexus and upper extremity peripheral nerve atlas using the investigational contrast agent ferumoxytol to achieve vascular suppression.

Matthew Koff, PhD, and Dr. Potter published interim results of a longitudinal RO1 study funded by the National Institutes of Health. Annual MRI exams were used to evaluate patients who underwent total hip arthroplasty during the course of the study. The results found MRI was able to detect adverse local tissue reactions in patients with hip resurfacing arthroplasty, even as the patients were able to maintain high function. The study was highlighted in Clinical Orthopaedics and Related Research. We have also focused on the use of advanced quantitative imaging techniques to evaluate the meniscus in the knee of basketball players and swimmers during the competitive season. The results of the study received a best poster award at the 2021 Annual Meeting of the Orthopaedic Research Society.

Clinical Expansion

J. Levi Chazen, MD, was appointed Director of Spine Imaging in 2021. As a neuroradiologist, Dr. Chazen has been working in collaboration with the Spine, Physiatry, Neurology, and Pain-Anesthesia service lines to update brain and spine imaging protocols for state-of-the-art patient imaging and diagnostics.

Innovations in 3D spine imaging continue in collaboration with Drs. Sneag and Tan. AI-augmented deep learning reconstruction (DL recon) imaging of the spine denoises both 2D and volumetric scans and allows the visualization of critical anatomy, including individual nerve rootlets (Fig 2A).

Dr. Chazen has expertise in the identification and treatment of cerebrospinal fluid (CSF) leaks, both in the setting of spontaneous intracranial hypotension (SIH) and from iatrogenic causes post-dural puncture or durotomy. Innovative imaging techniques for identification of CSF leak and often elusive CSF-venous fistula are now available at HSS, including specialized CT myelography (Fig 2B) as well as MR myelography without contrast and following the administration of intrathecal gadolinium.

In addition to 3D and AI-augmented spinal imaging, ongoing research projects include the use of radiofrequency ablation to treat refractory cervicogenic headache from C1-C2 lateral mass osteoarthritis (Fig 2C).

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Fig 1: 3D neuroimaging. (A) 3D isotropic fat suppressed T2 FLAIR showing normal midline appearance of the cerebrum and posterior fossa. (B) Axial post-contrast T1-weighted BRAVO sequence showing exquisite gray-white detail and visualization of the internal cerebral veins (arrow). (C) Axial quantitative susceptibility mapping (QSM) illustrating normal intracranial phase-positive susceptibility signal from iron deposition within the globus pallidus interna (arrow). QSM processing performed on site by Ek Tsoon Tan, PhD.
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Fig 2: Spine imaging and interventions. (A) 3D axial T2 CUBE illustrating the C2 dorsal root ganglia (arrows) and both the C2 ventral and dorsal rootlets exiting the spinal cord. (B) Coronal CT myelogram showing an abnormal right T12-L1 spinal meningeal diverticulum with epidural contrast leakage in the setting of SIH/CSF leak. (C) Axial intraprocedural CT showing a radiofrequency ablation probe targeting the C2 dorsal root ganglion for relief of cervicogenic headache. Note the close proximity to the vertebral artery, highlighting the importance of quality imaging and interventionalist expertise.

After a hiatus in 2020 due to the COVID-19 crisis, the HSS musculoskeletal ultrasound course was successfully held in October, directed by ultrasound division chief O. Kenechi Nwawka, MD. Registrants from all over the country learned techniques to evaluate musculoskeletal conditions using ultrasound, participating in hands-on live model scanning sessions and injection workshop. As invited faculty, Dr. Nwawka also lectured at national and international professional society meetings on the topics of nerve injury and repair and ultrasound-guided musculoskeletal intervention.

The ultrasound division has continued and expanded interdisciplinary collaborations in musculoskeletal research with 15 active interdisciplinary research projects, six of which are funded by competitive grants. Collaborations have yielded recent publications on topics including nerve injury, shear wave elastography of muscle and perineural intervention. The goals for 2022 include publication of results from recently completed grant-funded studies on shear wave elastography in patellar tendinopathy and spastic cerebral palsy. Several pilot studies on nerve repair imaging and Achilles tendinopathy are also being completed in preparation for grant funding submission.

The HSS interventional radiology division, headed by Edward Yoon, MD, has expanded its offering to patients with chronic, debilitating pain. He performed the first-ever basivertebral nerve ablation case at HSS for vertebrogenic back pain and type 1-2 Modic change on MRI.

Dr. Yoon also taught at many cadaver courses for vertebral augmentation and presented at many national meetings regarding interventional spine procedures. He was awarded young investigators travel grant by the Society of Skeletal Radiology and presented at the annual meeting of RSNA regarding treatment of discogenic back pain with allograft injections. He was a coauthor in the largest vertebral augmentation registry ever presented, which showed decreased mortality in patients with osteoporotic compression fractures who were treated with augmentation compared to conservative management. Moreover, he was co-author on the largest randomized and blinded intradiscal allograft trial, which showed functional improvement and decrease in pain in patients with discogenic back pain.

Notable Studies

Queler SC, Tan ET, Geannette C, Prince M, Sneag DB. Ferumoxytol-enhanced vascular suppression in magnetic resonance neurography. Skeletal Radiol. 2021 Nov;50(11): 2255-2266.

Sneag DB, Zochowski KC, Tan ET. MR Neurography of Peripheral Nerve Injury in the Presence of Orthopedic Hardware: Technical Considerations. Radiology. 2021 Aug;300(2):246-259. doi: 10.1148/radiol.2021204039. Epub 2021 Jun 29. PMID: 34184933.

Queler SC, Towbin AJ, Milani C, Whang J, Sneag DB. Parsonage-Turner Syndrome Following COVID-19 Vaccination: MR Neurography. Radiology. 2021 Aug 17:211374. doi: 10.1148/radiol.2021211374. Epub ahead of print.

Tan ET, Queler SC, Lin B, Endo Y, Burge AJ, Sternberg J, et al. (2021). Improved nerve conspicuity with water-weighting and denoising in two-point Dixon magnetic resonance neurography. Magn Reson Imaging. 79:103–111.

Zochowski KC, Tan ET, Argentieri EC, Lin B, Burge AJ, Queler SC, Lebel RM, Sneag DB. Improvement of peripheral nerve visualization using a deep learning-based MR reconstruction algorithm. Magn Reson Imaging. 2021 Oct 29;85:186-192. doi: 10.1016/j.mri.2021.10.038. Epub ahead of print. PMID: 34715288.

Motovilova E, Tan ET, Taracila V, Vincent JM, Grafendorfer T, Shin J, Potter HG, Robb FJL, Sneag DB, Winkler SA. Stretchable self-tuning MRI receive coils based on liquid metal technology (LiquiTune). Sci Rep. 2021 Aug 10;11(1):16228. doi: 10.1038/s41598-021-95335-6. PMID: 34376703; PMCID: PMC8355233.

Koff MF, Gao MA, Neri JP, Chiu Y, Lin BQ, Burge AJ, Su E, Padgett D, Potter HG. Adverse Local Tissue Reactions are Common in Asymptomatic Individuals After Hip Resurfacing Arthroplasty: Interim Report from a Prospective Longitudinal Study Clin Orthop Relat Res. 2021 Dec 1;479(12):2633-2650.

Sneag DB, Zochowski KC, Tan ET. (2021). Magnetic Resonance Neurography of Peripheral Nerve Injury in the Presence of Orthopaedic Hardware: Technical Considerations. Radiology. doi:10.1148/radiol.2021204039.

Majeed K, Hanz SZ, Roytman M, Chazen JL, Greenfield JP. Identification and surgical ligation of spinal CSF-venous fistula. Surg Neurol Int. 2021 Oct 11;12:514. doi: 10.25259/SNI_539_2021. PMID: 34754564; PMCID: PMC8571184.

Roytman M, Ulrich CT, Chazen JL. Post-dural puncture pseudomeningocele ("arachnoid bleb"): An underrecognized etiology of spontaneous intracranial hypotension symptomatology. Clin Imaging. 2021 Dec;80:377-381. doi: 10.1016/j.clinimag.2021.08.023. Epub 2021 Sep 7. PMID: 34517304.

Chazen JL, Amrhein TJ. Arachnoiditis following epidural blood patch-An avoidable rare complication due to blind technique. Headache. 2021 Jun;61(6):972-973. doi: 10.1111/head.14145. Epub 2021 Jun 29. PMID: 34184259.

Nwawka OK, Weinstock-Zlotnick G, Lin B, Ko LM. Association of Clinical Assessments of Hand Function and Quantitative Ultrasound Metrics in First Carpometacarpal Osteoarthritis. HSS J. 2020 Dec;16(Suppl 2):420-424.

Endo Y, Sivakumaran T, Lee SC, Lin B, Fufa D. Ultrasound features of traumatic digital nerve injuries of the hand with surgical confirmation. Skeletal Radiol. 2021 Sep;50(9):1791-1800.

Beall DP, Davis T, DePalma MJ, Amirdelfan K, Yoon ES, Wilson GL, Bishop R, Tally WC, Gershon SL, Lorio MP, Meisel HJ, Langhorst M, Ganey T, Hunter CW. Viable Disc Tissue Allograft Supplementation; One- and Two-level Treatment of Degenerated Intervertebral Discs in Patients with Chronic Discogenic Low Back Pain: One Year Results of the VAST Randomized Controlled Trial. Pain Physician. 2021 Sep;24(6):465-477. PMID: 34554689.

Shonnard NH, Berven S, Anderson PA, Verschuyl E, Norwitz J, Shonnard N, Khor S, Wagoner DD, Yoon ES, Beall DP. Appropriate Management of Vertebral Fragility Fractures: Development of a Pathway Based on a Vertebral Compression Fracture Registry. Pain Physician. 2020 Jul;23(4):E343-E352. PMID: 32709180.

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