Radiologist preferences for faculty development initiatives to improve resident feedback in the era of competency-based medical education.

INTRODUCTION: Since 2022, all Canadian post-graduate medical programs have transitioned to a Competence by Design (CBD) model within a Competency-Based Medical Education (CBME) framework. The CBME model emphasized more frequent, formative assessment of residents to evaluate their progress towards predefined competencies in comparison to traditional medical education models. Faculty members therefore have increased responsibility for providing assessments to residents on a more regular basis, which has associated challenges. Our study explores faculty assessment behaviours within the CBD framework and assesses their openness to opportunities aimed at improving the quality of written feedback. Specifically, we explore faculty's receptiveness to routine metric performance reports that offer comprehensive feedback on their assessment patterns. METHODS: Online surveys were distributed to all 28 radiology faculty at Queen's University. Data were collected on demographics, feedback practices, motivations for improving the teacher-learner feedback exchange, and openness to metric performance reports and quality improvement measures. Following descriptive statistics, unpaired t-tests and one-way analysis of variance were conducted to compare groups based on experience and subspecialty. RESULTS: The response rate was 89% (25/28 faculty). 56% of faculty were likely to complete evaluations after working with a resident. Regarding the degree to which faculty felt written feedback is important, 62% found it at least moderately important. A majority (67%) believed that performance reports could influence their evaluation approach, with volume of written feedback being the most likely to change. Faculty expressed interest in feedback-focused development opportunities (67%), favouring Grand Rounds and workshops. CONCLUSION: Assessment of preceptor perceptions reveals that faculty recognize the importance of offering high-quality written feedback to learners. Faculty openness to quality improvement interventions for curricular reform relies on having sufficient time, knowledge, and skills for effective assessments. This suggests that integrating routine performance metrics into faculty assessments could serve as a catalyst for enhancing future feedback quality.

Neurological Impairment in Critically Ill Patients on Dialysis: Research Letter for the INCOGNITO-AKI Feasibility Study.

Background: Acute kidney injury (AKI) resulting in kidney replacement therapy is rising among critically ill adults. Long-term kidney replacement therapy and critical illness are independently linked to acute and prolonged cognitive impairment, and structural brain pathology. Poor regional cerebral oxygenation (rSO2) may be a contributing factor. Objective: To assess the feasibility of testing the association between intradialytic rSO2 and acute and long-term neurological outcomes. Design: Longitudinal observational study. Setting and Participants: We enrolled patients initiating continuous kidney replacement therapy or intermittent hemodialysis in the Kingston Health Sciences Centre (KHSC) Intensive Care Unit (ICU). Measurements and Methods: rSO2 was monitored during the first 72 hours of continuous kidney replacement therapy or throughout each intermittent hemodialysis session. We measured acute neurological impairment by daily delirium screening and long-term neurocognitive outcomes using the Kinarm robot, Repeatable Battery for the Assessment of Neuropsychological Status, and brain magnetic resonance imaging. Results: Of 484 ICU patients, 26 met the screening criteria. Two declined, and 13 met at least one exclusion criteria. Eleven patients were enrolled. Eight died in ICU, one died 2 months after discharge, and one declined follow-up. Data capture rates were high: rSO2/vitals (91.3%), and delirium screening and demographics (100%). Longitudinal testing was completed in 50% (1 of 2) of survivors. Limitations: Enrollment was low due to a variety of factors, limiting our ability to evaluate long-term outcomes. Conclusion: rSO2 and delirium data collection is feasible in critically ill patients undergoing kidney replacement therapy; high mortality limits follow-up.

Contexte: L'insuffisance rénale aiguë (IRA) menant à une thérapie de remplacement rénal est en augmentation chez les adultes aux soins intensifs. Un séjour aux soins intensifs et la thérapie de remplacement rénal à long terme sont indépendamment liés à des déficits cognitifs aigus et prolongés ainsi qu'à des pathologies structurelles du cerveau. La faible saturation régionale du cerveau en oxygène (rSO2) pourrait être un facteur contributif. Objectif: Évaluer la possibilité de tester l'association entre la rSO2 intradialytique et les résultats neurologiques aigus et chroniques. Type d'étude: Étude observationnelle longitudinale. Cadre et sujets de l'étude: Nous avons recruté des patients qui entamaient une thérapie de remplacement rénal en continu ou une hémodialyse intermittente à l'unité des soins intensifs (USI) du Kingston Health Sciences Centre (KHSC). Mesures et méthodologie: La rSO2 a été surveillée pendant les 72 premières heures de thérapie de remplacement rénal en continu, ou tout au long de chaque séance d'hémodialyse intermittente. Nous avons mesuré les déficits neurologiques aigus par un dépistage quotidien du délirium et les atteintes neurocognitives à long terme à l'aide du robot Kinarm, de la Repeatable Battery for the Assessment of Neuropsychological Status et de l'imagerie par résonance magnétique cérébrale. Résultats: Sur les 484 patients hospitalisés à l'USI, 26 répondaient aux critères de sélection. Deux ont refusé de participer à l'étude et treize satisfaisaient à au moins un critère d'exclusion. Onze patients ont été inclus à l'étude. Huit patients sont décédés à l'USI, un est décédé deux mois après sa sortie de l'hôpital et un a refusé le suivi. Les taux de saisie des données étaient élevés: rSO2 et paramètres vitaux (91,3 %), dépistage du délirium et démographie (100 %). Des tests longitudinaux ont été effectués chez 50 % (1 de 2) des survivants. Limites: Le taux d'inscription était faible en raison de divers facteurs, ce qui a limité notre capacité à évaluer les résultats à long terme. Conclusion: Il est possible de collecter des données sur la rSO2 et le délirium chez les patients de soins intensifs qui suivent une thérapie de remplacement rénal; un taux de mortalité élevé a limité le suivi. Trial Registration: clinicaltrials.gov, registration number NCT04722939.

The Brain Tumor Segmentation (BraTS-METS) Challenge 2023: Brain Metastasis Segmentation on Pre-treatment MRI.

Clinical monitoring of metastatic disease to the brain can be a laborious and timeconsuming process, especially in cases involving multiple metastases when the assessment is performed manually. The Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) guideline, which utilizes the unidimensional longest diameter, is commonly used in clinical and research settings to evaluate response to therapy in patients with brain metastases. However, accurate volumetric assessment of the lesion and surrounding peri-lesional edema holds significant importance in clinical decision-making and can greatly enhance outcome prediction. The unique challenge in performing segmentations of brain metastases lies in their common occurrence as small lesions. Detection and segmentation of lesions that are smaller than 10 mm in size has not demonstrated high accuracy in prior publications. The brain metastases challenge sets itself apart from previously conducted MICCAI challenges on glioma segmentation due to the significant variability in lesion size. Unlike gliomas, which tend to be larger on presentation scans, brain metastases exhibit a wide range of sizes and tend to include small lesions. We hope that the BraTS-METS dataset and challenge will advance the field of automated brain metastasis detection and segmentation.

Peering Into the Future: A First Look at the CBME Transition to Practice Stage in Diagnostic Radiology.

RATIONALE AND OBJECTIVES: Queen's University (Kingston, ON, Canada) adopted a competency-based medical education (CBME) curriculum for Diagnostic Radiology residency training in an accelerated manner in 2017, with the curriculum comprised of four stages of training. This article focuses on the final stage (Transition to Practice), during which assessment methods of the new national curriculum (implemented in July 2022) were piloted. This study aims to highlight the challenges and opportunities associated with the implementation of CBME in Diagnostic Radiology training and specific considerations for programs undergoing this curricular transition. MATERIALS AND METHODS: Ethics approval was provided by the affiliated hospital Research Ethics Board. All relevant electronic assessments pertaining to all trainees who had completed the Transition to Practice stage (n = 3) were collated, deidentified, analyzed, and presented in tabulated format. RESULTS: A total of 39 evaluations completed by 13 assessors were assessed, with an average time of 3 minutes and 6 seconds to complete an assessment form. Also, 95% of evaluations were rated as entrustments. However, no residents met the minimum number of required entrustments for all five stage-specific Entrustable Professional Activities. These 39 evaluations included 219 milestone rating scores, with 86% rated as "achieved." Following review by the residency program Competence Committee, all three residents were promoted from the Transition to Practice stage. CONCLUSION: Challenges in CBME implementation include the number and quality of resident assessments. Strategies for success may include providing clear guidelines and training for both faculty and residents, early identification and intervention, and adopting a holistic evaluation strategy. CBME has the potential to enhance medical education quality by emphasizing learner progress toward competency and providing personalized feedback and support.

Feasibility and Cost Analysis of Portable MRI Implementation in a Remote Setting in Canada.

OBJECTIVE: To conduct feasibility and cost analysis of portable MRI implementation in a remote setting where MRI access is otherwise unavailable. METHODS: Portable MRI (ultra-low field, 0.064T) was installed in Weeneebayko General Hospital, Moose Factory, Ontario. Adult patients, presenting with any indication for neuroimaging, were eligible for study inclusion. Scanning period was from November 14, 2021, to September 6, 2022. Images were sent via a secure PACS network for Neuroradiologist interpretation, available 24/7. Clinical indications, image quality, and report turnaround time were recorded. A cost analysis was conducted from a healthcare system's perspective in 2022 Canadian dollars, comparing cost of portable MRI implementation to transporting patients to a center with fixed MRI. RESULTS: Portable MRI was successfully implemented in a remote Canadian location. Twenty-five patients received a portable MRI scan. All studies were of diagnostic quality. No clinically significant pathologies were identified on any of the studies. However, based on clinical presentation and limitations of portable MRI resolution, it is estimated that 11 (44%) of patients would require transfer to a center with fixed MRI for further imaging workup. Cost savings were $854,841 based on 50 patients receiving portable MRI over 1 year. Five-year budget impact analysis showed nearly $8 million dollars saved. CONCLUSIONS: Portable MRI implementation in a remote setting is feasible, with significant cost savings compared to fixed MRI. This study may serve as a model to democratize MRI access, offer timely care and improved triaging in remote areas where conventional MRI is unavailable.

An Artificial Intelligence Training Workshop for Diagnostic Radiology Residents.

Purpose: To develop, implement, and evaluate feedback for an artificial intelligence (AI) workshop for radiology residents that has been designed as a condensed introduction of AI fundamentals suitable for integration into an existing residency curriculum. Materials and Methods: A 3-week AI workshop was designed by radiology faculty, residents, and AI engineers. The workshop was integrated into curricular academic half-days of a competency-based medical education radiology training program. The workshop consisted of live didactic lectures, literature case studies, and programming examples for consolidation. Learning objectives and content were developed for foundational literacy rather than technical proficiency. Identical prospective surveys were conducted before and after the workshop to gauge the participants' confidence in understanding AI concepts on a five-point Likert scale. Results were analyzed with descriptive statistics and Wilcoxon rank sum tests to evaluate differences. Results: Twelve residents participated in the workshop, with 11 completing the survey. An average score of 4.0 ± 0.7 (SD), indicating agreement, was observed when asking residents if the workshop improved AI knowledge. Confidence in understanding AI concepts increased following the workshop for 16 of 18 (89%) comprehension questions (P value range: .001 to .04 for questions with increased confidence). Conclusion: An introductory AI workshop was developed and delivered to radiology residents. The workshop provided a condensed introduction to foundational AI concepts, developed positive perception, and improved confidence in AI topics.Keywords: Medical Education, Machine Learning, Postgraduate Training, Competency-based Medical Education, Medical Informatics Supplemental material is available for this article. © RSNA, 2023.

Ultra-High Field 7-Tesla Magnetic Resonance Imaging and Electroencephalography Findings in Epilepsy.

PURPOSE: Assessment of patients for temporal lobe epilepsy (TLE) surgery requires multimodality input, including EEG recordings to ensure optimal surgical planning. Often EEG demonstrates abnormal foci not detected on 1.5T MRI. Ultra-high field MRI at 7T provides improved resolution of the brain. We investigated the utility of 7T MRI to detect potential anatomical abnormalities associated with EEG changes. METHODS: Ultra-high field data were acquired on a 7T MRI scanner for 13 patients with history of drug resistant TLE who had had EEG telemetry recordings. Qualitative evaluation of 7T imaging for presence of focal abnormalities detected on EEG was performed. Correlation of 7T MRI findings with EEG recordings of focal slowing or interictal epileptic spikes (IEDs), and seizures was performed. RESULTS: Assessment of 7T MRI demonstrated concordance with TLE as determined by the multidisciplinary team in 61.5% of cases (n = 8). Among these, 3 patients exhibited supportive abnormal 7T MRI abnormalities not detected by 1.5T MRI. In patients who underwent surgery, 72.7% had concordant histopathology findings with 7T MRI findings (n = 8). However, qualitative assessment of 7T images revealed focal anatomical abnormalities to account for EEG findings in only 15.4% of patients (n = 2). Other regions that were found to have localized IEDs in addition to the lesional temporal lobe, included the contralateral temporal lobe (n = 5), frontal lobe (n = 3), and parieto-occipital lobe (n = 2). CONCLUSION: Ultra-high field 7T MRI findings show concordance with clinical data. However, 7T MRI did not reveal anatomical findings to account for abnormalities detected by EEG.

Investigating the Association between Aortic Arch Variants and Intracranial Aneurysms.

BACKGROUND: There is an association between anterior cerebral artery vessel asymmetry and anterior communicating artery aneurysm, presumably based on flow dynamics. The purpose of this study is to investigate the potential relationship between aortic arch branching patterns and incidence of intracranial aneurysm. METHODS: This study included patients scanned over 1 year at our tertiary care center who underwent high-resolution imaging (computed tomography angiography or digital subtracted angiogram) of the head and neck arteries, aortic arch, and superior mediastinum. Exclusion criteria included patients with suboptimal images. Patient age, gender, aortic arch branching pattern, and the presence, location, and number of aneurysms were documented. RESULTS: Among the 1082 patients analyzed, 250 (23%) patients had a variant aortic arch branching pattern, 22 (8.8%) of whom had aneurysms. There were 104 patients with 126 aneurysms, with majority of patients with normal aortic arch branching pattern (n = 82, 79%). The most common variant was a common origin of the left common carotid artery and brachiocephalic trunk with or without direct origin of the left vertebral artery. Twenty-two patients with aneurysms had an aberrant aortic arch (21%), compared to 232 patients without an aneurysm (24%). Fischer exact test showed no statistically significant difference between the incidence of aneurysm with different aortic arch variant groups (two-tailed p-value = 0.715). CONCLUSION: To our knowledge, this is the first study to examine the association between aortic arch branching patterns and incidence of intracranial aneurysm. No significant association was found between aortic arch branching pattern and the incidence of intracranial aneurysm.

An adaptation-focused evaluation of Canada's first competency-based medical education implementation in radiology.

OBJECTIVES: Systematic program evaluation of the Queen's University diagnostic radiology residency program following transition to a competency-based medical education (CBME) curriculum. METHODS: Rapid Evaluation methodology and the Core Components Framework were utilized to measure CBME implementation. A combination of interviews and focus groups were held with program leaders (n = 6), faculty (n = 10), both CBME stream and traditional stream residents (n = 6), and program staff (n = 2). Interviews and focus groups were transcribed and analyzed abductively. Study team met with program leaders to review common themes and plan potential adaptations. RESULTS: Strengths of CBME implementation included more frequent and timely feedback as well as the role of the Academic Advisor. However, frontline faculty felt insufficiently supported with regards to the theory and practical implementation of the new curriculum and found assessment tools unintuitive. The circumstances surrounding the curricular implementation also resulted in some negative sentiment. Additional faculty and resident education workshops were identified as areas for improvement as well as changes to assessment tools for increased clarity. Residents overall viewed the changes favorably, with traditional stream residents indicating that they also had a desire for increased feedback. CONCLUSIONS: Rapid Evaluation is an effective method for program assessment following curricular change in diagnostic radiology. A departmental champion driving enthusiasm for change from within may be valuable. Adequate resident and faculty education is key to maximize change and smooth the transition. Advances in knowledge: This study provides insights for other radiology training programs transitioning to a CBME framework and provides a structure for programmatic assessment.

Identifying neurocognitive outcomes and cerebral oxygenation in critically ill adults on acute kidney replacement therapy in the intensive care unit: the INCOGNITO-AKI study protocol.

INTRODUCTION: Initiation of acute kidney replacement therapy (KRT) is common in critically ill adults admitted to the intensive care unit (ICU), and associated with increased morbidity and mortality. KRT has been linked to poor neurocognitive outcomes, leading to reduced quality of life and increased utilisation of healthcare resources. Adults on dialysis in the ICU may be particularly at risk of neurocognitive impairment, as survivors of critical illness are already predisposed to developing cerebrovascular disease and cognitive dysfunction long-term relative to healthy controls. Regional cerebral oxygen saturation may provide a critical early marker of long-term neurocognitive impairment in this population. This study aims to understand cerebral oxygenation in patients undergoing KRT (continuous or intermittent) in the ICU. These findings will be correlated with long-term cognitive and functional outcomes, and structural brain pathology. METHODS AND ANALYSIS: 108 patients scheduled to undergo treatment for acute kidney injury with KRT in the Kingston Health Sciences Centre ICU will be recruited into this prospective observational study. Enrolled patients will be assessed with intradialytic cerebral oximetry using near infrared spectroscopy. Delirium will be assessed daily with the Confusion Assessment Method-ICU (CAM-ICU) and severity quantified as cumulative CAM-ICU-7 scores. Neurocognitive impairment will be assessed at 3 and 12 months after hospital discharge using the Kinarm and Repeatable Battery for the Assessment of Neuropsychological Status. Structural brain pathology on MRI will also be measured at the same timepoints. Driving safety, adverse events and medication adherence will be assessed at 12 months to evaluate the impact of neurocognitive impairment on functional outcomes. ETHICS AND DISSEMINATION: This study is approved by the Queen's University Health Sciences/Affiliated Teaching Hospitals Research Ethics Board (DMED-2424-20). Results will be presented at critical care conferences, and a lay summary will be provided to patients in their preferred format. TRIAL REGISTRATION NUMBER: NCT04722939.

Creating a Competency-Based Medical Education Curriculum for Canadian Diagnostic Radiology Residency (Queen's Fundamental Innovations in Residency Education)-Part 2: Core of Discipline Stage.

PURPOSE: All postgraduate residency programs in Canada are transitioning to a competency-based medical education (CBME) model divided into 4 stages of training. Queen's University has been the first Canadian institution to mandate transitioning to CBME across all residency programs, including Diagnostic Radiology. This study describes the implementation of CBME with a focus on the third developmental stage, Core of Discipline, in the Diagnostic Radiology residency program at Queen's University. We describe strategies applied and challenges encountered during the adoption and implementation process in order to inform the development of other CBME residency programs in Diagnostic Radiology. METHODS: At Queen's University, the Core of Discipline stage was developed using the Royal College of Physicians and Surgeons of Canada's (RCPSC) competence continuum guidelines and the CanMEDS framework to create radiology-specific entrustable professional activities (EPAs) and milestones for assessment. New committees, administrative positions, and assessment strategies were created to develop these assessment guidelines. Currently, 2 cohorts of residents (n = 6) are enrolled in the Core of Discipline stage. RESULTS: EPAs, milestones, and methods of evaluation for the Core of Discipline stage are described. Opportunities during implementation included tracking progress toward educational objectives and increased mentorship. Challenges included difficulty meeting procedural volume requirements, inconsistent procedural tracking, improving feedback mechanisms, and administrative burden. CONCLUSION: The transition to a competency-based curriculum in an academic Diagnostic Radiology residency program is significantly resource and time intensive. This report describes challenges faced in developing the Core of Discipline stage and potential solutions to facilitate this process.

An evaluation of the diagnostic equivalence of 18F-FDG-PET between hybrid PET/MRI and PET/CT in drug-resistant epilepsy: A pilot study.

OBJECTIVE: Hybrid PET/MRI may improve detection of seizure-onset zone (SOZ) in drug-resistant epilepsy (DRE), however, concerns over PET bias from MRI-based attenuation correction (MRAC) have limited clinical adoption of PET/MRI. This study evaluated the diagnostic equivalency and potential clinical value of PET/MRI against PET/CT in DRE. MATERIALS AND METHODS: MRI, FDG-PET and CT images (n = 18) were acquired using a hybrid PET/MRI and a CT scanner. To assess diagnostic equivalency, PET was reconstructed using MRAC (RESOLUTE) and CT-based attenuation correction (CTAC) to generate PET/MRI and PET/CT images, respectively. PET/MRI and PET/CT images were compared qualitatively through visual assessment and quantitatively through regional standardized uptake value (SUV) and z-score assessment. Diagnostic accuracy and sensitivity of PET/MRI and PET/CT for SOZ detection were calculated through comparison to reference standards (clinical hypothesis and histopathology, respectively). RESULTS: Inter-reader agreement in visual assessment of PET/MRI and PET/CT images was 78 % and 81 %, respectively. PET/MRI and PET/CT were strongly correlated in mean SUV (r = 0.99, p < 0.001) and z-scores (r = 0.92, p < 0.001) across all brain regions. MRAC SUV bias was <5% in most brain regions except the inferior temporal gyrus, temporal pole, and cerebellum. Diagnostic accuracy and sensitivity were similar between PET/MRI and PET/CT (87 % vs. 85 % and 83 % vs. 83 %, respectively). CONCLUSION: We demonstrate here that PET/MRI with optimal MRAC can yield similar diagnostic performance as PET/CT. Nevertheless, further exploration of the potential added value of PET/MRI is necessary before clinical adoption of PET/MRI for epilepsy imaging.

Lumbar Intradural Neurenteric Cyst: A Rare Pathology in an Unusual Location.

A previously healthy 48-year-old female presented to the emergency department with a 2-week history of low back pain, progressive lower extremities weakness, and right leg numbness. There were no bowel or bladder dysfunction symptoms. Spine magnetic resonance imaging (MRI) showed an intradural cystic lesion dorsal to the spinal cord at the level of L1 measuring 1.6 × 2.1 × 4.1 cm, which was T1 hypointense and T2 hyperintense, with a small soft tissue component and no gadolinium enhancement (Figure 1). A small lipomatous component was also noted. There were no associated vertebral anomalies. The patient underwent a T12-L2 laminectomy and cyst resection, which was subtotal due to the cyst adherence to the conus medullaris. Histopathology showed characteristic features of a neurenteric cyst, with respiratory-type epithelium in the cyst wall (Figure 2). Eight months later, follow-up MRI showed no evidence of recurrence. The patient reported improved sensation in the lower extremities; however, there was some residual weakness predominantly in the proximal hip flexors bilaterally.

A Pilot Study on Diagnostic Radiology Residency Case Volumes From a Canadian Perspective: A Marker of Resident Knowledge.

PURPOSE: New guidelines from the Accreditation Council for Graduate Medical Education (ACGME) have proposed minimum case volumes to be obtained during residency. While radiology residency programs in Canada are accredited by the Royal College of Physicians and Surgeons of Canada, there are currently no minimum case volumes standards for radiology residency training in Canada. New changes in residency training throughout Canada are coming in the form of competency-based medical education. Using data from a pilot study, this article examines radiology resident case volumes among recently graduated cohorts of residents and determines whether there is a correlation between case volumes and measures of resident success. MATERIALS AND METHODS: Resident case volumes for 3 cohorts of graduated residents (2016-2018) were extracted from the institutional database. Achievement of minimum case volumes based on the ACGME guidelines was performed for each resident. Pearson correlation analysis (n = 9) was performed to examine the relationships between resident case volumes and markers of resident success including residents' relative knowledge ranking and their American College of Radiology (ACR) in-training exam scores. RESULTS: A statistically significant, positive correlation was observed between residents' case volume and their relative knowledge ranking (r = 0.682, P < .05). Residents' relative knowledge ranking was also statistically significant and positively correlated with their ACR in-training percentile score (r = 0.715, P < .05). CONCLUSIONS: This study suggests that residents who interpret more cases are more likely to demonstrate higher knowledge, thereby highlighting the utility of case volumes as a prognostic marker of resident success. As well, the results underscore the potential use of ACGME minimum case volumes as a prognostic marker. These findings can inform future curriculum planning and development in radiology residency training programs.

18F-FDG PET-guided diffusion tractography reveals white matter abnormalities around the epileptic focus in medically refractory epilepsy: implications for epilepsy surgical evaluation.

BACKGROUND: Hybrid PET/MRI can non-invasively improve localization and delineation of the epileptic focus (EF) prior to surgical resection in medically refractory epilepsy (MRE), especially when MRI is negative or equivocal. In this study, we developed a PET-guided diffusion tractography (PET/DTI) approach combining 18F-fluorodeoxyglucose PET (FDG-PET) and diffusion MRI to investigate white matter (WM) integrity in MRI-negative MRE patients and its potential impact on epilepsy surgical planning. METHODS: FDG-PET and diffusion MRI of 14 MRI-negative or equivocal MRE patients were used to retrospectively pilot the PET/DTI approach. We used asymmetry index (AI) mapping of FDG-PET to detect the EF as brain areas showing the largest decrease in FDG uptake between hemispheres. Seed-based WM fiber tracking was performed on DTI images with a seed location in WM 3 mm from the EF. Fiber tractography was repeated in the contralateral brain region (opposite to EF), which served as a control for this study. WM fibers were quantified by calculating the fiber count, mean fractional anisotropy (FA), mean fiber length, and mean cross-section of each fiber bundle. WM integrity was assessed through fiber visualization and by normalizing ipsilateral fiber measurements to contralateral fiber measurements. The added value of PET/DTI in clinical decision-making was evaluated by a senior neurologist. RESULTS: In over 60% of the patient cohort, AI mapping findings were concordant with clinical reports on seizure-onset localization and lateralization. Mean FA, fiber count, and mean fiber length were decreased in 14/14 (100%), 13/14 (93%), and 12/14 (86%) patients, respectively. PET/DTI improved diagnostic confidence in 10/14 (71%) patients and indicated that surgical candidacy be reassessed in 3/6 (50%) patients who had not undergone surgery. CONCLUSIONS: We demonstrate here the utility of AI mapping in detecting the EF based on brain regions showing decreased FDG-PET activity and, when coupled with DTI, could be a powerful tool for detecting EF and assessing WM integrity in MRI-negative epilepsy. PET/DTI could be used to further enhance clinical decision-making in epilepsy surgery.

Transoral robotic surgery for head and neck malignancies: Imaging features in presurgical workup.

The objective of this article was to review the indications for transoral robotic surgery (TORS) in head and neck malignancies. The role of imaging in patient selection will be specifically reviewed. TORS is a recently developed technique that allows minimally invasive surgeries to be performed in the head and neck. TORS has a role in the de-escalation of oropharyngeal cancers, which allows for lower doses of chemoradiation therapy (this is a technique currently in clinical trials). Additionally, this technique allows for less invasive surgery and decreases associated complications. TORS can also be performed at other subsites. Cross-sectional imaging has a prominent role to help identify suitable candidates for this type of surgery. This article will review important anatomy and staging related to TORS. Additionally, the key imaging features for patient selection (indications and contraindications) will be presented along with case illustrations.

Minimally Invasive Unilateral Percutaneous Transfracture Fixation of a Hangman's Fracture Using Neuronavigation and Intraoperative Fluoroscopy.

BACKGROUND: Traumatic spondylolisthesis or hangman's fracture is a common cervical spine fracture. Most cases of traumatic spondylolisthesis are treated nonoperatively with external immobilization. The indications for surgery have generally included fracture instability or failed nonoperative management. Operative stabilization can be performed through either anterior or posterior approaches and has generally required instrumentation using open methods. We propose a technique for surgical repair of hangman's fracture that is minimally invasive and motion preserving using recent advances in 3-dimensional image-guidance technology. We believe this method represents another option in the treatment of hangman's fractures, because it allows for immediate stabilization, prompt recovery, and quick mobilization. CASE DESCRIPTION: We present the case of 2 patients with hangman's fractures who had undergone surgical unilateral transfixation with minimally invasive percutaneous screw placement. In both cases, we used 3-dimensional neuronavigation and bidirectional intraoperative fluoroscopy. The operative time from incision to closure was <30 minutes. Preparation and positioning after intubation varied from 40 to 150 minutes. No intraoperative complications occurred. Both patients were discharged within 48 hours postoperatively. The follow-up examinations at 3 months, 12 months, and 5 years revealed healthy bony fusion on computed tomography imaging and an excellent clinical recovery. CONCLUSION: We have provided 2 examples in which minimally invasive unilateral fixation of hangman's fractures proved to be safe and effective. In both cases, the patients were immediately relieved of their pain, quickly mobilized, and promptly discharged. The achievement of successful fusion confirmed at the follow-up examinations.

Evaluation of ex-vivo 9.4T MRI in post-surgical specimens from temporal lobe epilepsy patients.

PURPOSE: This study evaluates hippocampal pathology through usage of ultra-high field 9.4T ex-vivo imaging of resected surgical specimens in patients who have undergone temporal lobe epilepsy surgery. METHOD AND MATERIALS: This is a retrospective interpretation of prospectively acquired data. MRI scanning of resected surgical specimens from patients who have undergone temporal lobe epilepsy surgery was performed on a 9.4T small bore Varian MR magnet. Structural images employed a balanced steady-state free precession sequence (TrueFISP). Six patients (3 females; 3 males) were included in this study with an average age at surgery of 40.7 years (range 20Y_"60) (one was used as a control reference). Two neuroradiologists qualitatively reviewed the ex-vivo MRIs of resected specimens while blinded to the histopathology reports for the ability to identify abnormal features in hippocampal subfield structures. RESULTS: The hippocampal subfields were reliably identified on the 9.4T ex-vivo scans in the hippocampal head region and hippocampal body region by both neuroradiologists in all 6 patients. There was high concordance to pathology for abnormalities detected in the CA1, CA2, CA3 and CA4 subfields. Detection of abnormalities in the dentate gyrus was also high with detection in 4 of 5 cases. The Cohen's kappa between the two neuroradiologists was calculated at 0.734 SE=0.102. CONCLUSIONS: Ex-vivo 9.4T specimen imaging can detect abnormalities in CA1, CA2, CA3, CA4 and DG in both the hippocampal head and body. There was good concordance between qualitative findings and histopathological abnormalities for CA1, CA2, CA3, CA4 and DG.