Faculty Bibliography

BACKGROUND AND PURPOSE/OBJECTIVE:Stereotactic radiosurgery (SRS) is an effective management approach for many patients with head and neck paragangliomas (HNPGLs). However, treated paragangliomas may not significantly decrease in volume or subjective enhancement on conventional MRI. We investigated the utility of dynamic contrast-enhanced MRI (DCE-MRI) using golden-angle radial sparse parallel (GRASP) technique to detect vascular changes in HNPGLs after SRS, hypothesizing that controlled paragangliomas would demonstrate evidence of lower permeability post-SRS. MATERIALS AND METHODS/METHODS:We retrospectively analyzed 14 patients with HNPGLs managed with gamma-knife SRS from 2015 to 2024 at our institution who had GRASP DCE-MRI before and after treatment. Tumor enhancement kinetics were quantified using wash-in slope, wash-out slope, peak enhancement, and time to peak, normalized to the superior sagittal sinus. Tumors volumes were calculated from postcontrast images. Pre- and post-SRS parameters were compared using paired statistical tests. RESULTS:Median time between pre- and post-SRS imaging was 26 months. Tumor volume decreased modestly (median change -0.18 mL, p=.001) or remained stable in all but one case. Significant reductions were observed in normalized wash-in slope (p=.01), wash-out slope (p=.01), and peak enhancement (p=.02) following SRS. CONCLUSIONS:GRASP DCE-MRI detected significant changes in enhancement kinetics of HNPGLs following SRS, suggesting that dynamic imaging may serve as a biomarker of treatment response. These findings support the integration of functional imaging alongside conventional MRI sequences in post-treatment assessment of HNPGL.

OBJECTIVES/UNASSIGNED:To better understand the implications of tumor size on auditory brainstem implant (ABI) categories of auditory performance (CAP) score to facilitate more precise patient counselling. DESIGN/UNASSIGNED:Single-center retrospective chart review. SETTING/UNASSIGNED:Tertiary referral center. PARTICIPANTS/UNASSIGNED:Patients > 18 years old with neurofibromatosis type 2 who underwent ABI placement between the years 2009 and 2023 were included. Patients with prior surgical resection were excluded to reduce the potential of previous cochlear nucleus trauma confounding results. MAIN OUTCOME MEASURES/UNASSIGNED:Ipsilateral tumor volume was measured from the preoperative MRI, and the primary endpoint was the 1-year CAP score. RESULTS/UNASSIGNED: = 0.010). CONCLUSION/UNASSIGNED:Increased tumor size has a negative correlation with ultimate ABI performance. There were patients in this study with larger tumor sizes who still benefited from ABI placement. While larger tumor size should not be a contraindication for ABI placement, understanding the role tumor size can have on performance variation can serve to improve tumor management strategies and preoperative counselling.

PURPOSE/OBJECTIVE:U.S. ACGME-approved neuroradiology fellowship positions continue to increase in the setting of a national radiologist shortage, and the challenges faced by expanding fellowship programs could vary with program size. The aim of our project was to survey neuroradiology fellowship Program Directors (PDs) at US ACGME-approved diagnostic neuroradiology fellowship programs to better understand the challenges and practices in fellow recruitment, growth of fellowship class size, and other factors. MATERIALS AND METHODS/METHODS:An online 21-question survey was distributed to PDs of US ACGME-approved diagnostic neuroradiology fellowships (n=91). All variables were appropriately summarized and correlations assessed. Programs were dichotomized as large (greater than median number of approved spots) or small (less than or equal to median). Differences between large and small programs were evaluated with appropriate statistical tests. Effects associated with P<0.05 were considered statistically significant. RESULTS:PDs from 60/91(66%) institutions had evaluable responses. For the 2024-2025 academic year, 37/60(62%) programs filled all their fellowship positions. The proportion of large programs (20/25,80%) filling all their positions was higher (P=0.017) than small programs (17/35,49%). Large programs (14/25,56%) increased the number of fellowship positions more than small programs (5/35,14.3%) since 2019-2020 (P=0.002). Small programs had more difficulty filling all fellowship positions (19/34,54%) than large programs (5/25,20%) through national residency match program (P<0.001). Both large and small programs were challenged by other large programs and geographical location. Unique challenges for large and small programs were the high number of fellowship positions and competition from nearby programs, respectively. Length of PD tenure was not statistically correlated with the ability to fill the fellowship program (P=0.75). Small programs had a larger median of ABR-alternative pathway candidates [29%(0-66.7%)] than large programs [9.5%(0-16.7%)], the distribution did not differ significantly (P=0.19). CONCLUSIONS:Large neuroradiology fellowship programs filled all ACGME-approved positions with less difficulty and often increased their available fellowship positions in the last 5 years, compared to small programs. Competition from large programs and geographical location challenge recruitment for neuroradiology fellowship programs irrespective of size. Strategies for expanding and filling U.S. neuroradiology fellowships should vary based on fellowship size with a goal to help alleviate the on-going radiologist shortage.

OBJECTIVES/UNASSIGNED:To develop and study a novel means of imaging auditory brainstem implant (ABI) paddle placement utilizing postoperative MRI images to determine correlation between ABI performance and ideal paddle placement properties. DESIGN/UNASSIGNED:Single-center retrospective review and image analysis. SETTING/UNASSIGNED:Tertiary referral center. PARTICIPANTS/UNASSIGNED:Patients >18 years old who received an ABI from 2009 to 2023 and had subsequent MRI and auditory performance testing completed. MAIN OUTCOME MEASURES/UNASSIGNED:ABI paddle angulation and insertion depth measure, in addition to categories of auditory performance (CAP) score. RESULTS/UNASSIGNED: = 0.049) once patients with large tumor burden were excluded. Insertion depth and axial angulation showed a negative correlation, in which higher insertion depth was associated with a decrease in axial angulation value, although not statistically significant. CONCLUSION/UNASSIGNED:We present a novel means of measuring ABI paddle placement utilizing MRI to improve the objectivity of paddle placements assessments. Multicenter collaboration to increase the number of patients studied with this new measurement scheme will be required before stronger measurement associations can be determined.

Facial nerve palsy is a debilitating condition with substantial physical and psychosocial impacts. Facial reanimation encompasses surgical reconstructive procedures aimed at restoring the functions of the facial nerve to improve function and quality of life in patients with facial palsy. This educational review outlines the essential principles for interpreting imaging studies for facial reanimation including fundamental anatomy, technical descriptions and imaging appearances of common reconstructive procedures, and key findings that should be included when reporting studies for patients being considered for facial reanimation. The information provided in this review equips radiologists to contribute effectively to a multidisciplinary team necessary for the treatment of patients with facial nerve palsy.

BACKGROUND AND PURPOSE/OBJECTIVE:Photon-counting CT (PCCT) offers several advantages over conventional CT for cochlear implant (CI) imaging, including improved spatial resolution, and both signal-to-noise and contrast-to-noise ratios. However, the optimal PCCT reconstruction parameters for CI imaging has not been established. This study compared six PCCT reconstruction approaches for temporal bone CI imaging in a multi-reader design. MATERIALS AND METHODS/METHODS:20 patients with CIs (24 implants) underwent temporal bone PCCT on a NAEOTOM Alpha scanner. Raw data was reconstructed using six different algorithms, as follows: Hr84 0.2mm T3D (head-regular, sharpness level 84, polyenergetic), Hr84 0.4mm T3D, Qr56 0.4mm iMAR T3D (quantitative-regular, sharpness level 56, iterative metal artifact reduction), Qr76 0.4mm M_140 (virtual monoenergetic 140 keV), Qr76 0.4mm M_70 (virtual monoenergetic 70 keV), and Qr76 0.4mm T3D.Two fellowship-trained neuroradiologists independently rated electrode visibility and overall image quality for all implants, and wire visibility for implants with visible wires, on 0-2 Likert scales. Inter-reader agreement was assessed with quadratic weighted Cohen's kappa. A mixed effects model was used to evaluate reconstruction differences for each metric. RESULTS:Mean patient age was 50.9 ± 26 years; 8 were women. Inter-reader agreement was substantial for electrode visibility (κ = 0.66) and overall image quality (κ = 0.79), and moderate for wire visibility (κ = 0.52). Reconstruction type significantly affected all three metrics. The sharp kernel reconstructions (Hr84 0.2mm T3D and Hr84 0.4mm T3D) consistently ranked highest, with significantly greater scores than most other reconstructions. Qr56 0.4mm iMAR T3D was the lowest rated in every category, significantly worse than all other reconstructions. CONCLUSIONS:PCCT reconstruction parameters substantially influence postoperative CI image quality. Ultra-high-resolution reconstructions provided the best combination of artifact suppression and fine structural detail, while iterative MAR and high-keV monoenergetic reconstructions performed the worst. These findings can guide reconstruction selection to optimize PCCT protocols for CI evaluation.

Several masses and pseudomasses may present in the orbit, and cross-sectional imaging plays a crucial role in interrogation of these lesions. A strong understanding of orbital anatomy and the pathologies that may affect the structures within allows the radiologist to narrow the differential diagnosis. This article aims to discuss these pathologies with attention to the site of origin, to provide a practical approach to imaging of orbital tumors. While many lesions have characteristic appearances, many features overlap and require correlation with tissue sampling. Nevertheless, imaging is an essential first step to diagnosis, surgical planning, surveillance, and follow-up of orbital masses.

Vision loss is a common medical problem that can arise secondary to a variety of pathologies including trauma, ischemia, infection or inflammation, demyelination, and mass lesions anywhere along the visual pathway. Most nontraumatic pathology to the globe is diagnosed by ophthalmologic examination and does not require imaging. When needed, the choice of imaging study is directed at the known or suspected cause and the expected anatomic location of the insult along the visual pathway. This document focuses on the appropriateness of imaging in adults where vision loss is the primary presenting symptom. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Horner syndrome is a combination of signs and symptoms caused by abnormalities in the oculosympathetic pathway. Typically, patients present with ipsilateral miosis, ptosis, and anhidrosis. Imaging the oculosympathetic pathway is complex because of its extensive course, need for targeted protocols, and the wide range of pathology that can cause it. For this document, we focus our attention on workup guidelines based on clinical features: 1) acuity (acute, nonacute including chronic, insidious, and unknown onset), 2) painless or painful (neck pain, occipital region pain, or headaches), 3) whether there is a history of trauma (any form of injury to the chest, neck, or head area, including iatrogenic injury from recent procedure and surgery), and 4) absence or presence of localizing brain, cranial nerve, or spinal cord neurological signs or symptoms. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

BACKGROUND AND PURPOSE/OBJECTIVE:Nationally clinical volumes are rising, putting greater pressure on radiologists to read more and in turn jeopardizing the academic missions of many training programs. The purpose of this study was to survey neuroradiology fellowship program directors (PDs) to identify reasonable expected trainee and faculty interpretive volumes, common barriers to study interpretation, and threats to fellowship program viability. MATERIALS AND METHODS/METHODS:This was an institutional review board-approved survey study disseminated to neuroradiology fellowship PDs through the American Society of Neuroradiology. This Web-based survey included basic program information regarding practice setting, faculty size, fellowship size, and multiple questions related to interpretative volumes, barriers to study interpretation, threats to program viability, etc. Summary statistics were computed for count and rank variables. For survey questions by using ranking, cumulative ranks across all institutions were computed with a statistical ranking procedure based on Savage scores. RESULTS:Forty-three of 85 PDs responded to the survey. Median daily interpretive expectations for fellows were 20 daily cases during the first 6 months of the year and 30 during the second 6 months. Median daily interpretive expectations for faculty working with fellows was 32 daily cases during the first 6 months of the year and 38.5 during the second 6 months. Telephone calls from technologists and referring clinicians and protocoling were identified as major barriers to interpreting studies. Perceived major threats to program viability included increasing case volumes, understaffing, and burnout. CONCLUSIONS:Reasonable interpretive volumes determined by fellowship directors ranged between 20-30 daily cases for fellows and 32-38.5 daily cases for faculty working with fellows. Common barriers to interpretation were related to phone call interruptions and protocoling. Perceived major program viability threats remain centered on increasing clinical volumes and burnout.