Faculty Bibliography

We present a radiology-pathology case series of 3 patients with coronavirus disease 2019 (COVID-19) with acute ischemic stroke due to fulminant carotid thrombosis overlying mild atherosclerotic plaque and propose a novel stroke mechanism: COVID-associated carotid atherothrombosis.

During the Severe Acute Respiratory Syndrome Coronavirus 2 (COVID-19) pandemic, neuroradiology practices have experienced a paradigm shift in practice, which affected everything from staffing, workflow, work volumes, conferences, resident and fellowship education, and research. This article highlights adaptive strategies that were undertaken at the epicenter of the outbreak in New York City during the past 4-6 weeks, as experienced by 5 large neuroradiology academic departments.

BACKGROUND AND PURPOSE:Neurodegeneration after mild traumatic brain injury may manifest as decreasing regional brain volume that evolves from months to years following mild traumatic brain injury and is associated with worse clinical outcomes. We hypothesized that quantitative brain volume derived from CT of the head, performed for clinical indications during routine care, would change with time and provide insights into the putative neuroinflammatory response to mild traumatic brain injury. MATERIALS AND METHODS:We searched the electronic medical record of our institution for NCCTs of the head performed in patients with mild traumatic brain injury and included those who also underwent NCCTs of the head 1 month to 1 year before and after mild traumatic brain injury for an indication unrelated to trauma. Controls underwent 3 sequential NCCTs of the head with indications unrelated to trauma. The whole-brain and intracranial volume groups were computed using ITK-SNAP. Brain volumes normalized to intracranial volumes were compared across time points using the Wilcoxon signed-rank test. RESULTS:= .927). There was no significant difference between normalized brain volumes in the 48 controls. CONCLUSIONS:A decrease in brain volume following mild traumatic brain injury is detectable on CT and is not seen in similar patients with non-mild traumatic brain injury during a similar timeframe. Given the stability of brain volume before mild traumatic brain injury, CT volume loss may represent the subtle effects of neurodegeneration.

OBJECTIVE:We instituted a new, simple CT pulmonary angiography (CTPA) contrast material timing protocol using a standard empiric delay to replace our previous timing bolus method. This study tests the hypothesis that the empiric protocol more consistently produces diagnostic quality images of both the pulmonary arteries and the aorta with lower radiation exposure. MATERIALS AND METHODS/METHODS:We performed a retrospective review of consecutive CTPAs for 2months both before and after the protocol change. Pulmonary artery and aortic enhancement, patient characteristics, radiation exposure and results of CTPA were analyzed. RESULTS:, P<0.01). Pulmonary embolism positivity rate was non-significantly higher in the timing bolus vs the empiric timing group (19% and 13%, P=0.1). CONCLUSION/CONCLUSIONS:A simple empiric timing protocol for CTPA has robust performance compared to a timing bolus protocol. Empiric timing preserves the required high diagnostic quality for evaluation of the pulmonary arteries with the added benefits of aortic enhancement and lower radiation exposure.

OBJECTIVE:The purpose of this article is to determine the natural history of adrenal cysts on the basis of long-term imaging follow-up. MATERIALS AND METHODS/METHODS:This retrospective study included patients with adrenal cysts who had at least 12 months of imaging follow-up (1993-2010). Medical records were reviewed. Two radiologists reviewed imaging examinations in consensus and recorded wall thickness (thin, ≤ 3 mm; thick, > 3 mm), septations, and calcification. CT attenuation value, MRI signal intensity, the presence or absence of enhancement, and typical sonographic features were used to confirm fluid content of the lesions. Cyst wall enhancement was recorded (thin, ≤ 3 mm and smooth; thick, > 3 mm). Cyst diameter on the initial and most remote follow-up examinations was compared. The Wilcoxon matched-pairs signed rank test was applied to assess statistically significant differences in size and CT attenuation on follow-up examinations. RESULTS:Twenty patients with unilateral adrenal cysts (seven male and 13 female patients; mean age, 44 years; range, 10-75 years) had a mean imaging follow-up period of 64 months (range, 12-198 months). CT, MRI, and ultrasound examinations were obtained in 19, 11, and 13 patients, respectively. Cysts were diagnosed by lack of enhancement on CT or MRI in 12 patients, typical sonographic features in three patients, and combination of CT and sonographic or MRI features in five patients. Signal intensities typical for fluid were found on all MRI examinations, attenuations of less than 20 HU on 17 of 19 (89%) CT examinations, and features of either simple or mildly complicated cysts on all sonograms. Thin walls, wall calcifications, and thin septations were found in 20 (100%), 12 (60%), and four (20%) lesions, respectively. During the follow-up of 20 lesions, the median cyst diameter increased by 26.0% (interquartile range, 6.8-68.4%) in 12 (60%) patients, decreased by 32.9% (interquartile range, 7.1-42.8%) in six (30%) patients, and was unchanged in two (10%) patients. The median baseline CT attenuation values did not significantly change on follow-up CT examinations (p = 0.72). No patient developed a complication of adrenal cyst. Four patients had histologically confirmed benign adrenal cysts. CONCLUSION/CONCLUSIONS:Interval enlargement of an adrenal cyst is frequent and as an isolated finding does not indicate malignancy or presence of a complication. However, some adrenal cysts may decrease or remain stable in size over time.

BACKGROUND AND PURPOSE: There is no standardized curriculum currently available at most institutions for establishing procedural competency in trainees performing cervicocerebral angiography. The purpose of this study was to evaluate a simple learning program to supplement the teaching of basic cervicocerebral angiography. MATERIALS AND METHODS: An 11-session interactive curriculum was implemented covering anatomic, clinical, and radiographic topics for the novice cervicocerebral angiographer. The target learner was the neuroradiology fellow. Data were gathered regarding fellow comfort level on topics relating to cervicocerebral angiography by using a 5-point Likert scale. Improvement in scores on knowledge-based questions after completion of the curriculum was calculated (McNemar test). Trainee-perceived utility of the program was also recorded by using a 5-point Likert scale. Focus sessions were held at the completion of the curriculum to gather feedback regarding the strengths and weaknesses of the program from participants. RESULTS: Ten subjects were enrolled in this pilot study for 3 years. Topics where participants reported a poor initial comfort level (4 or higher) included selection of injection rates and volumes and reformation of reverse-curve catheters. Trainees demonstrated a statistically significant change in the distribution of scores of 29.3% (49.4%-78.7% correct response rate, P < .0001). The average perceived utility was 1.5 (1 = most useful, 5 = least useful). CONCLUSIONS: This simple learning program was a useful adjunct to the training of fellows in diagnostic cervicocerebral angiography, resulting in quantitative improvements in knowledge.