Evidence for an adverse impact of remote readouts on radiology resident productivity: Implications for training and clinical practice.

After their rapid adoption at the onset of the coronavirus pandemic, remote case reviews (remote readouts) between diagnostic radiology residents and their attendings have persisted in an increasingly remote workforce, despite relaxing social distancing guidelines. Our objective was to evaluate the impact of the transition to remote readouts on resident case volumes after the recovery of institutional volumes. We tabulated radiology reports co-authored by first-to-third-year radiology residents (R1-R3) between July 1 and December 31 of the first pandemic year, 2020, and compared to the prior two pre-pandemic years. Half-years were analyzed because institutional volumes recovered by July 2020. Resident volumes were normalized to rotations, which were in divisions categorized by the location of the supervising faculty during the pandemic period; in 'remote' divisions, all faculty worked off-site, whereas 'hybrid' divisions had a mix of attendings working on-site and remotely. All residents worked on-site. Data analysis was performed with Student's t test and multivariate linear regression. The largest drops in total case volume occurred in the two remote divisions (38% [6,086 to 3,788], and 26% [11,046 to 8,149]). None of the hybrid divisions with both in-person and remote supervision decreased by more than 5%. With multivariate regression, a resident assigned to a standardized remote rotation in 2020 would complete 32% (253 to 172) fewer studies than in identical pre-pandemic rotations (coefficent of -81.6, p = .005) but would be similar for hybrid rotations. R1 residents would be expected to interpret 40% fewer (180 to 108) cases on remote rotations during the pandemic (coefficient of -72.3, p = .007). No significant effect was seen for R2 or R3 residents (p = .099 and p = .29, respectively). Radiology residents interpreted fewer studies during remote rotations than on hybrid rotations that included in-person readouts. As resident case volume is correlated with clinical performance and board pass rate, monitoring the readout model for downstream educational effects is essential. Until evidence shows that educational outcomes remain unchanged, radiology residencies may wish to preserve in-person resident readouts, particularly for junior residents.

The Effectiveness of Spaced Learning, Interleaving, and Retrieval Practice in Radiology Education: A Systematic Review.

PURPOSE: Radiology is a highly complex field that requires mastery over an ever-expanding body of knowledge. Spaced learning, interleaving, and retrieval practice are evidence-based learning strategies that enhance long-term retention of information. The aim of this systematic review is to assess the effectiveness of these interventions in the setting of radiology education. METHODS: The authors searched MEDLINE, Embase, PsycInfo, ERIC, and forward and backward citations for studies published between database inception and February 19, 2023. Eligibility criteria for included studies were randomized and quasi-randomized controlled trials that investigated the impact of spaced, interleaved, or retrieval practice on knowledge retention of medical trainees after education related to medical imaging as assessed by postinterventional examination scores. RESULTS: Of 1,316 records reviewed, 8 studies met eligibility criteria. Two studies investigated spaced learning, two studies interleaving, and six studies retrieval practice, including two trials that evaluated interventions incorporating both spaced learning and retrieval practice. Five of eight studies reported statistically significant differences between interventional and control groups on either immediate or delayed postinterventional examinations. CONCLUSIONS: Despite extensive evidence in support of spaced, interleaved, and retrieval practice within the broader literature, few studies have examined the effectiveness of these strategies in radiology education. Additional trials are required to evaluate the usefulness of incorporating these techniques into educational programs related to medical imaging.

Definitive local therapy to head and neck squamous cell carcinoma with distant metastasis.

Objectives: Data on the efficacy of including definitive local therapy to the primary site for head and neck squamous cell carcinoma (HNSCC) patients with synchronous distant metastasis are lacking. In multiple different solid tumor types, there has been benefit when using systemic therapy followed by local consolidative therapy (stereotactic ablative radiotherapy or surgery) directed at metastases. We proposed to retrospectively evaluate patients at our institution that received definitive treatment to the primary. Methods: Single institution retrospective study evaluating 40 patients with metastatic HNSCC treated with definitive surgery (55%) or chemoradiation (45%) to the primary site from 2000 to 2020. The major endpoints were overall survival (OS) and progression-free survival (PFS) for the total population and multiple sub-groups. Some variables were evaluated with multiple covariates Cox model. Results: The median PFS was 8.6 months (95% CI, 6.4-11.6), and OS was 14.2 months (95% CI, 10.9-27.5). In 28% of patients that received induction therapy, there was a twofold increase in median overall survival to 27.5 months. In the 33% of patients that received anti-PD-1 mAb as part of their treatment course, the median OS was significantly increased to 41.7 months (95% CI, 8.7-NR) versus 12.1 months (95% CI, 8.4-14.4) with a 5-year OS of 39%. Multivariate analysis for OS showed significance for age at diagnosis, use of IO, and number of metastatic sites. Conclusion: We observed impressive survival outcomes in metastatic HNSCC patients treated with definitive local therapy to the primary site in addition to induction and/or immunotherapy. Further study is warranted.Level of Evidence: 3.

Imaging predictors of successful surgical treatment of hemifacial spasm.

Identify preoperative imaging findings in hemifacial spasm patients that predict the post-surgical success following microvascular decompression. This is a retrospective study of patients who were diagnosed with hemifacial spasm, had a dedicated cranial nerve MRI, and underwent microvascular decompression for hemifacial spasm. Bilateral facial nerves were interrogated for neurovascular compression. If neurovascular compression was identified, we recorded whether the offending vessel was an artery, a vein or both. The location of the neurovascular compression (proximal nerve versus distal nerve) was noted. The severity of the neurovascular compression was categorized as contact versus deformity of the nerve. Patients were contacted to determine their post-operative spasm status. The relationships between imaging findings and post-surgical outcome were assessed by Chi-square tests, and odds ratios were calculated to quantify the degree of association. The study included 212 patients. Upon follow up, 192 patients were spasm free (90.57%). Imaging findings on the symptomatic side were as follows: arterial neurovascular compression was seen in 207 patients (97.64%), venous only neurovascular compression in two patients (0.94%), and no neurovascular compression in three patients (1.42%). Arterial neurovascular compression along the proximal, susceptible segment of the nerve was observed in 202 patients (95.28%); deformity was observed more commonly than contact alone. Arterial neurovascular compression along the distal segment only of the nerve was observed in five patients (2.36%). In patients with arterial neurovascular compression of the proximal and distal portions of the nerve, 93.07% and 60.0% of patients were spasm-free respectively. If venous neurovascular compression only was observed on imaging, 0% of patients were spasm-free. Patients with arterial neurovascular compression of the susceptible segment are much more likely to be spasm free than patients without this imaging finding, [odds ratio 20.14 (CI 5.08, 79.81), P-value <0.0001]. When comparing the two groups of arterial neurovascular compression (deformity versus contact), no statistically significant difference in outcomes was observed. In patients with hemifacial spasm undergoing microvascular decompression, imaging findings do predict surgical outcome. Patients with arterial neurovascular compression of the proximal, susceptible portion of the nerve are much more likely to be spasm free after surgery than those without this imaging finding. The imaging findings inform the risk benefit analysis and discussion with patients before they undergo microvascular decompression for hemifacial spasm.

Prevalence and severity of neurovascular compression in hemifacial spasm patients.

Hemifacial spasm is typically caused by vascular compression of the proximal intracranial facial nerve. Although the prevalence of neurovascular compression has been investigated in a cohort of patients with classical trigeminal neuralgia, the prevalence and severity of neurovascular compression has not been well characterized in patients with hemifacial spasm. We aimed to investigate whether presence and severity of neurovascular compression are correlated to the symptomatic side in patients with hemifacial spasm. All patients in our study were evaluated by a physician who specializes in the management of cranial nerve disorders. Once hemifacial spasm was diagnosed on physical exam, the patient underwent a dedicated cranial nerve protocol magnetic resonance imaging study on a 3 T scanner. Exams were retrospectively reviewed by a neuroradiologist blinded to the symptomatic side. The presence, severity, vessel type, and location of neurovascular compression along the facial nerve was recorded. Neurovascular compression was graded as contact alone (vessel touching the facial nerve) versus deformity (indentation or deviation of the nerve by the culprit vessel). A total of 330 patients with hemifacial spasm were included. The majority (232) were female while the minority (98) were male. The average age was 55.7 years. Neurovascular compression (arterial) was identified on both the symptomatic (97.88%) and asymptomatic sides (38.79%) frequently. Neurovascular compression from an artery along the susceptible/proximal portion of the nerve was much more common on the symptomatic side (96.36%) than on the asymptomatic side (12.73%), odds ratio = 93.00, P < 0.0001. When we assessed severity of arterial compression, the more severe form of neurovascular compression, deformity, was noted on the symptomatic side (70.3%) much more frequently than on the asymptomatic side (1.82%) (odds ratio = 114.00 P < 0.0001). We conclude that neurovascular compression that results in deformity of the susceptible portion of the facial nerve is highly associated with the symptomatic side in hemifacial spasm.

Transition to a virtual multidisciplinary tumor board during the COVID-19 pandemic: University of Pittsburgh experience.

Multidisciplinary conferences (MDC) are an important component of head and neck oncologic care including diagnosis, treatment, and survivorship. Virtual MDC allows for improved collaboration between providers at distant sites and proper allocation of health care resources in a time of crisis. When approached systematically, a virtual MDC is feasible to design and implement in a large academic medical center with multiple satellite hospitals.

Development and Evaluation of a Preoperative Trigeminal Neuralgia Scoring System to Predict Long-Term Outcome Following Microvascular Decompression.

BACKGROUND: Microvascular decompression (MVD) can be an effective intervention for trigeminal neuralgia (TN); however, an optimal system for patient selection and surgical outcome prediction has not been defined. OBJECTIVE: To develop and validate a preoperative TN grading system for the prediction of long-term pain relief after MVD. METHODS: This retrospective cohort study included consecutive patients suffering unilateral TN who underwent MVD with >18-mo follow-up. A grading system was formulated using 3 previously validated preoperative characteristics. The primary end-point was long-term, pain-free status without use of medication. Ability to predict pain-free status was analyzed by multiple regression and assessed by area under the receiver operating characteristic curve (AUC). Clinical utility to predict MVD success and reduce unnecessary surgeries was assessed by decision-curve analysis. RESULTS: Of 208 patients analyzed, 73% were pain-free without medication at >18-mo follow-up. Pain-free status was predicted by classical TN type, positive response to carbamazepine and/or oxcarbazepine, and presence and nature of neurovascular compression demonstrated on MRI (all P < .01). The TN grading system demonstrated good discriminatory ability for prediction of pain-free status (AUC 0.85, 95% CI 0.80-0.91). Decision-curve analysis demonstrated a net reduction of 20 cases likely to be unsuccessful per 100 patients evaluated with this grading system above a decision threshold of 80%. CONCLUSION: This TN grading system reliably predicts long-term pain-free status without medications following MVD. The use of the TN grading system as part of a comprehensive work-up may reduce the number of unsuccessful operations.

Significance of degree of neurovascular compression in surgery for trigeminal neuralgia.

OBJECTIVE: The aim of this study was to identify preoperative imaging predictors of surgical success in patients with classic trigeminal neuralgia (cTN) undergoing microvascular decompression (MVD) via retrospective multivariate regression analysis. METHODS: All included patients met criteria for cTN and underwent preoperative MRI prior to MVD. MR images were blindly graded regarding the presence and severity (i.e., mild or severe) of neurovascular compression (NVC). All patients were contacted by telephone to determine their postoperative pain status. RESULTS: A total of 79 patients were included in this study. Sixty-two patients (78.5%) were pain-free without medication following MVD. The following findings were more commonly observed with the symptomatic nerve when compared to the contralateral asymptomatic nerve: NVC (any form), arterial compression alone, NVC along the proximal trigeminal nerve, and severe NVC (p values < 0.0001). The only imaging variable that was a statistically significant predictor of being pain-free without medication following MVD was severe NVC. Patients with severe NVC were 6.36 times more likely to be pain-free following MVD compared to those without severe NVC (p = 0.007). CONCLUSIONS: In patients with cTN undergoing MVD, severe NVC on preoperative MRI is a strong predictor of an excellent surgical outcome.

Trigeminal Nerve Compression Without Trigeminal Neuralgia: Intraoperative vs Imaging Evidence.

BACKGROUND: While high-resolution imaging is increasingly used in guiding decisions about surgical interventions for the treatment of trigeminal neuralgia, direct assessment of the extent of vascular contact of the trigeminal nerve is still considered the gold standard for the determination of whether nerve decompression is warranted. OBJECTIVE: To compare intraoperative and magnetic resonance imaging (MRI) findings of the prevalence and severity of vascular compression of the trigeminal nerve in patients without classical trigeminal neuralgia. METHODS: We prospectively recruited 27 patients without facial pain who were undergoing microvascular decompression for hemifacial spasm and had undergone high-resolution preoperative MRI. Neurovascular contact/compression (NVC/C) by artery or vein was assessed both intraoperatively and by MRI, and was stratified into 3 types: simple contact, compression (indentation of the surface of the nerve), and deformity (deviation or distortion of the nerve). RESULTS: Intraoperative evidence of NVC/C was detected in 23 patients. MRI evidence of NVC/C was detected in 18 patients, all of whom had intraoperative evidence of NVC/C. Thus, there were 5, or 28% more patients in whom NVC/C was detected intraoperatively than with MRI (Kappa = 0.52); contact was observed in 4 of these patients and compression in 1 patient. In patients where NVC/C was observed by both methods, there was agreement regarding the severity of contact/compression in 83% (15/18) of patients (Kappa = 0.47). No patients exhibited deformity of the nerve by imaging or intraoperatively. CONCLUSION: There was moderate agreement between imaging and operative findings with respect to both the presence and severity of NVC/C.

Resident Case Volume Correlates with Clinical Performance: Finding the Sweet Spot.

RATIONALE AND OBJECTIVES: To determine whether the total number of studies interpreted during radiology residency correlates with clinical performance as measured by objective criteria. MATERIALS AND METHODS: We performed a retrospective cohort study of three graduating classes of radiology residents from a single residency program between the years 2015-2017. The total number of studies interpreted by each resident during residency was tracked. Clinical performance was determined by tracking an individual resident's major discordance rate. A major discordance was recorded when there was a difference between the preliminary resident interpretation and final attending interpretation that could immediately impact patient care. Accreditation council for graduate medical education milestones at the completion of residency, Diagnostic radiology in-training scores in the third year, and score from the American board of radiology core exam were also tabulated. Pearson correlation coefficients and polynomial regression analysis were used to identify correlations between the total number of interpreted films and clinical, test, and milestone performance. RESULTS: Thirty-seven residents interpreted a mean of 12,709 studies (range 8898-19,818; standard deviation [SD] 2351.9) in residency with a mean major discordance rate of 1.1% (range 0.34%-2.54%; stand dev 0.49%). There was a nonlinear correlation between total number of interpreted films and performance. As the number of interpreted films increased to approximately 16,000, clinical performance (p = 0.004) and test performance (p = 0.01) improved, but volumes over 16,000 correlated with worse performance. CONCLUSION: The total number of studies interpreted during radiology training correlates with performance. Residencies should endeavor to find the "sweet spot": the amount of work that maximizes clinical exposure and knowledge without overburdening trainees.

MRI Findings and Outcomes in Patients Undergoing Microvascular Decompression for Glossopharyngeal Neuralgia.

BACKGROUND AND PURPOSE: Glossopharyngeal neuralgia causes extreme paroxysmal pain in the posterior pharynx, tonsillar region, base of tongue, or deep ear, that is, the distribution of the glossopharyngeal nerve. Some cases of glossopharyngeal neuralgia are associated with neurovascular conflict, usually by the posterior inferior cerebellar artery. Such symptomatic compression occurs only in proximal, centrally myelinated portions of the glossopharyngeal nerve near the brainstem. Microvascular decompression provides effective and durable pain relief for properly selected patients with medically refractory glossopharyngeal neuralgia. The purpose of this study is to describe a tailored MRI evaluation of neurovascular conflict in glossopharyngeal neuralgia to improve candidate selection for microvascular decompression. METHODS: Our team developed a glossopharyngeal neuralgia imaging and evaluation protocol including a grading system for neurovascular conflict of the glossopharyngeal nerve and applied it to evaluate candidates for microvascular decompression. RESULTS: Our team grades neurovascular conflict as "contact" (vessel touching nerve without intervening cerebrospinal fluid) versus "deformation" (deviation or distortion of nerve from its normal course by the offending vessel). MRIs of patients with glossopharyngeal neuralgia demonstrate proximal neurovascular conflict. Postoperative MRI demonstrates separation of the glossopharyngeal nerve from the offending vessel. CONCLUSION: A tailored glossopharyngeal neuralgia imaging evaluation protocol is presented. We believe this approach has helped improve microvascular decompression outcomes and reduce unnecessary procedures at our institution. Further research may elucidate whether clinical and imaging features, including neurovascular conflict severity, predict surgical outcome for glossopharyngeal neuralgia.

Diagnosis and endoscopic endonasal management of nontraumatic pseudoaneurysms of the cranial base.

BACKGROUND: Nontraumatic pseudoaneurysms of the cranial base are rare and present unique diagnostic and treatment dilemmas compared with both true aneurysms and pseudoaneurysms outside of the cranial base. There is a dearth of knowledge regarding the management of these complicated lesions. METHODS: Nontraumatic pseudoaneurysms of the cranial base internal carotid artery (ICA) were retrospectively identified at the University of Pittsburgh Medical Center through a key word search of cranial base cases from 2010 to 2017. RESULTS: Three cases were identified, demonstrating pseudoaneurysms of the cavernous and petrous ICA. Each patient underwent diagnostic work-up with computed tomography, magnetic resonance imaging, and angiography, followed by endovascular occlusion and endoscopic endonasal surgery, which resulted in relief of presenting complaints and ablation of the pseudoaneurysm. CONCLUSION: Symptomatic cranial base pseudoaneurysms should undergo treatment to obliterate the aneurysm and relieve the mass effect. First, formal angiography is necessary for accurate diagnosis and treatment planning. Next, endovascular occlusion is performed, with a preference for coiling or endoluminal reconstruction with a flow diverter. Last, endoscopic intervention follows in cases where: (1) decompression of vital structures is indicated; (2) diagnosis of the pseudoaneurysm cannot be definitively confirmed with angiography; or (3) the etiology of the confirmed pseudoaneurysm requires further investigation.

Do Residency Selection Factors Predict Radiology Resident Performance?

RATIONALE AND OBJECTIVES: The purpose of our study is to determine what information in medical student residency applications predicts radiology residency success as defined by objective clinical performance data. MATERIALS AND METHODS: We performed a retrospective cohort study of residents who entered our institution's residency program through the National Resident Matching Program as postgraduate year 2 residents and completed the program over the past 2 years. Medical school grades, selection to Alpha Omega Alpha (AOA) Honor Society, United States Medical Licensing Examination (USMLE) scores, publication in peer-reviewed journals, and whether the applicant was from a peer institution were the variables examined. Clinical performance was determined by calculating each resident's cumulative major discordance rate for on-call cases the resident read and gave a preliminary interpretation. A major discordance was defined as a difference between the preliminary resident and the final attending interpretations that could immediately impact the care of the patient. A multivariate logistic regression was performed to determine significant variables. RESULTS: Twenty-seven residents provided preliminary reports on call for 67,145 studies. The mean major discordance rate was 1.08% (range 0.34%-2.54%). Higher USMLE Step 1 scores, publication before residency, and election to AOA Honor Society were all statistically significant predictors of lower major discordance rates (P values 0.01, 0.01, and <0.001, respectively). CONCLUSIONS: Overall resident performance was excellent. There are predictors that help select the better performing residents, namely higher USMLE Step 1 scores, one to two publications during medical school, and election to AOA in the junior year of medical school.

Nasoseptal flap necrosis: a rare complication of endoscopic endonasal surgery.

OBJECTIVE The vascularized nasoseptal flap (NSF) has become the workhorse for skull base reconstruction during endoscopic endonasal surgery (EES) of the ventral skull base. Although infrequently reported, as with any vascularized flap the NSF may undergo ischemic necrosis and become a nidus for infection. The University of Pittsburgh Medical Center's experience with NSF was reviewed to determine the incidence of necrotic NSF in patients following EES and describe the clinical presentation, imaging characteristics, and risk factors associated with this complication. METHODS The electronic medical records of 1285 consecutive patients who underwent EES at the University of Pittsburgh Medical Center between January 2010 and December 2014 were retrospectively reviewed. From this first group, a list of all patients in whom NSF was used for reconstruction was generated and further refined to determine if the patient returned to the operating room and the cause of this reexploration. Patients were included in the final analysis if they underwent endoscopic reexploration for suspected CSF leak or meningitis. Those patients who returned to the operating room for staged surgery or hematoma were excluded. Two neurosurgeons and a neuroradiologist, who were blinded to each other's results, assessed the MRI characteristics of the included patients. RESULTS In total, 601 patients underwent NSF reconstruction during the study period, and 49 patients met the criteria for inclusion in the final analysis. On endoscopic exploration, 8 patients had a necrotic, nonviable NSF, while 41 patients had a viable NSF with a CSF leak. The group of patients with a necrotic, nonviable NSF was then compared with the group with viable NSF. All 8 patients with a necrotic NSF had clinical and laboratory evidence indicative of meningitis compared with 9 of 41 patients with a viable NSF (p < 0.001). Four patients with necrotic flaps developed epidural empyema compared with 2 of 41 patients in the viable NSF group (p = 0.02). The lack of NSF enhancement on MR (p < 0.001), prior surgery (p = 0.043), and the use of a fat graft (p = 0.004) were associated with necrotic NSF. CONCLUSIONS The signs of meningitis after EES in the absence of a clear CSF leak with the lack of NSF enhancement on MRI should raise the suspicion of necrotic NSF. These patients should undergo prompt exploration and debridement of nonviable tissue with revision of skull base reconstruction.

PET/CT for Head and Neck Squamous Cell Carcinoma: Should We Routinely Include the Head and Abdomen?

OBJECTIVE: The purpose of our study was to determine the diagnostic and therapeutic yield of the head and abdomen portions of PET/CT scans of patients with head and neck squamous cell cancer (HNSCC) to determine whether these areas should be routinely included with PET/CT of the neck and chest. MATERIALS AND METHODS: Patients with pathologically proven HNSCC who underwent full-body PET/CT were evaluated for metastases to the head, chest, and abdomen. Medical records were reviewed to determine whether the head and abdominal findings changed the clinical management, beyond the findings in the neck and chest. RESULTS: Five hundred ninety-eight patients who underwent 1625 PET/CT scans were included. All studies included the head, neck, and chest. For 542 of 598 patients (91%), the PET/CT scans included the abdomen. Two of 598 patients (0.3%) had distant calvarial metastases. Neither of the calvarial metastases changed patient management. Twelve of 542 patients (2.2%) had abdominal metastases. For 10 of 542 patients (1.8%), the abdominal findings changed patient management. Thoracic metastases were found in 82 of 598 patients (13.7%). The total rate of distant metastases to the head and abdomen in patients with thoracic metastatic disease was 12.2% (10/82), whereas in patients without thoracic metastases, it was 0.8% (4/460). CONCLUSION: Routine extension of PET/CT scans to include the head and abdomen in patients with HNSCC is not indicated. For patients without evidence of thoracic metastases, routine PET/CT examinations should include the neck and chest only.

Facial spasms, but not hemifacial spasm: a case report and review of literature.

INTRODUCTION: Facial spasms represent a complicated array of neurological motor disorders with unique diagnostic and treatment algorithms. Due to the rarity of many of these disorders in the pediatric population, special care must be taken in identifying subtle differences in presentation of these disorders. METHODS: We present a case of a 3-year-old boy diagnosed with a brainstem ganglioglioma, Chiari 1 malformation, and a 2-year history of left-sided facial spasms. Stereotyped facial contractions and subtle eye deviation occurred every 10 s, with downward movement rather than upward elevation of the eyebrow. RESULTS: MRI revealed absence of a clear compressive vessel of the centrally-myelinized portion of the facial nerve, and EMG of the left facial nerve demonstrated no abnormal motor response or evidence of "lateral spread." Given these findings, a diagnosis of hemifacial seizures was made. Microvascular decompression was not recommended, and botulinum toxin injection was not pursued; however, the patient has remained refractory to antiepileptic drugs, possibly due to biochemical alteration by his ganglioglioma. He may eventually require surgical debulking should his symptoms progress. CONCLUSION: Hemifacial spasm is a well-recognized disorder, but similar conditions can, at times, imitate its appearance. While our patient presented with facial spasms, his clinical history, examination, and radiographic and electrophysiological findings were more consistent with hemifacial seizures secondary to a brainstem lesion, rather than hemifacial spasms. It is important to distinguish the two entities, as misdiagnosis and inappropriate diagnostic or therapeutic measures may be taken inadvertently.

MRI of the Trigeminal Nerve in Patients With Trigeminal Neuralgia Secondary to Vascular Compression.

OBJECTIVE: Trigeminal neuralgia is a debilitating facial pain disorder, frequently caused by vascular compression of the trigeminal nerve. Vascular compression that results in trigeminal neuralgia occurs along the cisternal segment of the nerve. CONCLUSION: Imaging combined with clinical information is critical to correctly identify patients who are candidates for microvascular decompression. The purpose of this article is to review trigeminal nerve anatomy and to provide strategies for radiologists to recognize important MRI findings in patients with trigeminal neuralgia.

White Matter Injuries in Mild Traumatic Brain Injury and Posttraumatic Migraines: Diffusion Entropy Analysis.

Purpose To determine the performance of Shannon entropy (SE) as a diagnostic tool in patients with mild traumatic brain injury (mTBI) with posttraumatic migraines (PTMs) and those without PTMs on the basis of analysis of fractional anisotropy (FA) maps. Materials and Methods The institutional review board approved this retrospective study, with waiver of informed consent. FA maps were obtained and neurocognitive testing was performed in 74 patients with mTBI (57 with PTM, 17 without PTM). FA maps were obtained in 22 healthy control subjects and in 20 control patients with migraine headaches. Mean FA and SE were extracted from total brain FA histograms and were compared between patients with mTBI and control subjects and between patients with and those without PTM. Mean FA and SE were correlated with clinical variables and were used to determine the areas under the receiver operating characteristic curve (AUCs) and likelihood ratios for mTBI and development of PTM. Results Patients with mTBI had significantly lower SE (P < .001) and trended toward lower mean FA (P = .07) compared with control subjects. SE inversely correlated with time to recovery (TTR) (r = -0.272, P = .02). Patients with mTBI with PTM had significantly lower SE (P < .001) but not mean FA (P = .15) than did other patients with mTBI. SE provided better discrimination between patients with mTBI and control subjects than mean FA (AUC = 0.92; P = .01), as well as better discrimination between patients with mTBI with PTM and those without PTM (AUC = 0.85; P < .001). SE of less than 0.751 resulted in a 16.1 increased likelihood of having experienced mTBI and a 3.2 increased likelihood of developing PTM. Conclusion SE more accurately reveals mTBI than mean FA, more accurately reveals those patients with mTBI who develop PTM, and inversely correlates with TTR. (©) RSNA, 2016.