An Innovative Medical Student Neuroradiology Elective Course: Active Learning Through a Case-Based Approach.

RATIONALE AND OBJECTIVES: Traditional radiology education in clerkships is focused on observational and passive learning from radiology faculty. The aim of this study was to validate a new case-based radiology course challenging medical students to independently scroll through picture archival and communications system cases, thereby actively learning and improving their understanding and education of radiology. MATERIALS AND METHODS: This study used PowerPoint files to present and review various brain, spine, and head and neck clinical cases to simulate real time case review process by Radiologists. Students were tested with an online quiz based on the cases both before and after the review. Quizzes were distributed and responses collected at both times via a Google Form. Students had access to correct answers and feedback after the post-case quiz. A Radiologist was available for an hour of individualized committed teaching time to answer student questions after the post-case quiz. After the elective, there was an option for both quantitative and qualitative feedback. RESULTS: All 54 students who took part in this independent case-based program indicated satisfaction and improvement in their understanding of Neuroradiology. Post-quiz classes demonstrated objective improvement in understanding. CONCLUSION: This program represents a viable, supplementary approach to traditional radiology education that should be considered for future use and duplication at other institutions.

Ipsilateral weakness caused by ipsilateral stroke: A case series.

INTRODUCTION: There are few reported cases of ipsilateral weakness following ischemic or hemorrhagic stroke. In these rare cases, ipsilateral weakness is typically the result of damage to uncrossed components of the corticospinal tract (CST) which were recruited in response to previous CST injury. PATIENTS AND METHODS: We report a series of six cases of acute ipsilateral weakness or numbness following a hemorrhagic or ischemic stroke from three medical institutions in Saudi Arabia. RESULTS: Three of these patients presented with right-sided weakness caused by an ipsilateral right hemispheric stroke, while two exhibited left-sided symptoms and one had only left-sided numbness. In all six cases, the ipsilateral corona radiata, internal capsule, basal ganglia, insula, and thalamus were involved. No concomitant opposite hemisphere or brainstem lesion in none of the patients was evident. Two patients had previous strokes affecting the brainstem and left corona radiata, respectively. Complete stroke workup to reveal the cause of stroke was carried out, however no functional MRI was performed. CONCLUSION: Ischemic or hemorrhagic stroke may indeed result in ipsilateral weakness or numbness, though in very rare cases. We assume that the most likely mechanism of their ipsilateral weakness subsequent to the ipsilateral stroke was a functional reorganization favoring CST pathways within the ipsilateral hemisphere.

Predictors of Early Mortality for Mechanically Ventilated Spontaneous Intracerebral Hemorrhage Patients.

Introduction Spontaneous intracerebral hemorrhage (sICH) carries a high mortality burden. Limited data are available on early mortality (EM) and sICH. This study attempted to identify the independent predictors of EM and analyze the mortality characteristics for mechanically ventilated patients with sICHs at a tertiary care hospital over a period of five years. Methods An Institutional Review Board (IRB)-approved and Health Insurance Portability and Accountability Act (HIPPA)-compliant retrospective analysis was performed on sICH patients admitted at the University of Mississippi Medical Center Neuroscience Intensive Care Unit between January 1, 2013, to December 31, 2017. Patients were divided into two cohorts: EM cohort (death within seven days of admission) versus survivor cohort (alive more than seven days after admission). Demographic, comorbidity, clinical, and radiographic data were collected for each patient. Outcomes were compared utilizing student t-test or Mann-Whitney U tests for continuous variables. Logistic regression analysis was performed to determine independent predictors of EM. Results A total of 204 mechanically ventilated patients with sICHs, with a mean age of 59.73 (SD ±14.30), mostly African American (137, 67%), were included in the study. The characteristics of the two cohorts were comparable except the EM cohort had a lower proportion of patients with hypertension and end-stage renal disease; lower median Glasgow Coma Score (GCS) on admission; lower proportion of surgical evacuation and external ventricular drain (EVD) placement; higher proportion of lobar hemorrhage, brainstem involvement, midline shift, hydrocephalus, intraventricular hemorrhage component, and right-sided intracerebral hemorrhage (ICH); higher median ICH score; and higher ICH volume compared to the survivor cohort. Overall, the mortality of mechanically ventilated sICH patients in this institution was 53% (N=109), with 47% (N=96) not surviving beyond seven days. Logistic regression analysis revealed that ICH volume and brainstem involvement increased the odds of EM, while a history of hypertension, surgical evacuation, and EVD placement decreased the odds of EM. Conclusions This study on mechanically ventilated sICH patients identified ICH volume and brainstem involvement as independent predictors of increased EM. History of hypertension, EVD placement, and surgical evacuation decreased its odds. Further studies should be conducted to explore potentially modifiable processes that can improve patient outcomes, most importantly EM, especially in this cohort of patients.

Quantification of hematoma and perihematomal edema volumes in intracerebral hemorrhage study: Design considerations in an artificial intelligence validation (QUANTUM) study.

BACKGROUND: Hematoma and perihematomal edema volumes are important radiographic markers in spontaneous intracerebral hemorrhage. Accurate, reliable, and efficient quantification of these volumes will be paramount to their utility as measures of treatment effect in future clinical studies. Both manual and semi-automated quantification methods of hematoma and perihematomal edema volumetry are time-consuming and susceptible to inter-rater variability. Efforts are now underway to develop a fully automated algorithm that can replace them. A (QUANTUM) study to establish inter-quantification method measurement equivalency, which deviates from the traditional use of measures of agreement and a comparison hypothesis testing paradigm to indirectly infer quantification method measurement equivalence, is described in this article. The Quantification of Hematoma and Perihematomal Edema Volumes in Intracerebral Hemorrhage study aims to determine whether a fully automated quantification method and a semi-automated quantification method for quantification of hematoma and perihematomal edema volumes are equivalent to the hematoma and perihematomal edema volumes of the manual quantification method. METHODS/DESIGN: Hematoma and perihematomal edema volumes of supratentorial intracerebral hemorrhage on 252 computed tomography scans will be prospectively quantified in random order by six raters using the fully automated, semi-automated, and manual quantification methods. Primary outcome measures for hematoma and perihematomal edema volumes will be quantified via computed tomography scan on admission (<24 h from symptom onset) and on day 3 (72 ± 12 h from symptom onset), respectively. Equivalence hypothesis testing will be conducted to determine if the hematoma and perihematomal edema volume measurements of the fully automated and semi-automated quantification methods are within 7.5% of the hematoma and perihematomal edema volume measurements of the manual quantification reference method. DISCUSSION: By allowing direct equivalence hypothesis testing, the Quantification of Hematoma and Perihematomal Edema Volumes in Intracerebral Hemorrhage study offers advantages over radiology validation studies which utilize measures of agreement to indirectly infer measurement equivalence and studies which mistakenly try to infer measurement equivalence based on the failure of a comparison two-sided null hypothesis test to reach the significance level for rejection. The equivalence hypothesis testing paradigm applied to artificial intelligence application validation is relatively uncharted and warrants further investigation. The challenges encountered in the design of this study may influence future studies seeking to translate artificial intelligence medical technology into clinical practice.

Lymph Node Dissection: Principles and Postoperative Imaging.

The management of neck nodes in head and neck cancer is critical, given a markedly increased poor prognosis in patients with nodal metastasis. The surgical management of neck nodes has undergone radical changes secondary to a paradigm shift from curative surgery to nonsurgical organ and function-preserving options, such as radiation therapy. In the neck after treatment, radiologists should be familiar with imaging findings in various types of neck dissections and post-chemoradiation changes, along with signs of residual or recurrent disease. A multidisciplinary approach is essential with well-designed evidence-based surveillance imaging protocols and standardized reporting.

"Virtual Radiology Workstation": Improving Medical Students' Radiology Rotation.

BACKGROUND: Radiology education in clinical clerkship is increasingly important. There is an acute need for active engagement and self-directed learning by medical students rotating in radiology compared with mainly observational current learning practice involving shadowing in the reading room. ACTIVITY: "Virtual Radiology Workstations" supplemented by PowerPoint presentation of normal radiologic anatomy were introduced for fourth-year medical student radiology electives. RESULTS AND DISCUSSION: All 18 students were satisfied with this new teaching model and agreed their understanding of imaging procedures, and recognition of basic anatomic structures improved. It also resulted in efficient utilization of both the teachers' and the students' time.

Malignant cerebellar edema in three-year-old girl following accidental opioid ingestion and fentanyl administration.

A three-year-old girl was found altered with an unknown timeline. Gas chromatography mass spectrometry was positive for hydromorphone, dihydrocodeine, and hydrocodone. Initial computed tomography and magnetic resonance imaging suggested a malignant cerebellar edema not confined to a vascular distribution. She received fentanyl boluses on hospital days 0 and 1 before receiving a continuous infusion on day 1. On day 3, she had an episode of acute hypertension and bradycardia. Emergent computed tomography showed an evolving hydrocephalus and similar diffuse edema throughout both cerebellar hemispheres. External ventricular drain was placed to relieve the increased intracranial pressure. Following drain placement and fentanyl discontinuation, the patient recovered, though not without fine- and gross-motor deficits at the four-month follow-up. Our case adds to a handful of case reports of opioid toxicity in pediatric patients that present as toxic leukoencephalopathy. Though the mechanism is poorly understood, it has been suggested to be a consequence of the neurotoxic effects of the drug, which has particular affinity for µ opioid receptors-the primary opioid receptor found in the cerebellum. Clinicians would do well to recognize that this syndrome is primarily caused by direct toxicity rather than ischemia. This case adds insight by suggesting that lipophilic opioid analgesics may worsen this neurotoxicity. When intervening with mechanical ventilation, clinicians should consider avoiding lipophilic opioid drugs for analgesia until the pathogenesis of cerebellar edema is better understood.

Brain Death: Diagnosis and Imaging Techniques.

Brain death (BD) is an irreversible cessation of functions of the entire brain, including the brainstem. The diagnosis of BD is made on clinical grounds and neurologic examination. In the United States, clinical criteria set by the American Academy of Neurology (AAN) emphasize 3 specific clinical findings to confirm BD, which include coma, absence of brainstem reflexes and apnea. Ancillary tests are needed when neurologic examination or apnea test cannot be performed. AAN recommended ancillary tests include electroencephalogram, which confirms electrical activity loss; catheter cerebral angiogram, which confirms loss of cerebral blood flow; as well as transcranial Doppler and nuclear scintigraphy. Digital subtraction angiography remains the gold standard for confirmation of lack of cerebral blood flow. On 99m Techentium hexa methyl propylene amine oxime or 99mTechnetium-ethylene cysteine diethyl ester (99mTc-ethylene cysteine diethyl ester) Nuclear scintigraphy, lack of intracranial radiotracer uptake, correlates with BD. Although imaging studies like computed tomography angiogram (CTA), MR angiogram, CT perfusion, and MR perfusion are frequently used, they are currently not recommended by AAN. However, they hold tremendous promise in future as imaging tools in the armamentarium of a radiologist investigating BD as adjunct imaging to clinical findings. Imaging markers for BD on CTA include nonopacification of the cortical middle cerebral arteries and internal cerebral veins. On CT perfusion, there is lack of cerebral blood flow and blood volume in brainstem. Residual brain perfusion can occur with reduced intracranial pressure as in decompressive craniectomy, ventricular drainage and multiple skull fractures leading to false-negative results. On magnetic resonance imaging, there can be massive brain edema with herniations, poor gray or white matter differentiation, diffuse diffusion restriction, and nonvisualization of intracranial vessels on MR angiogram. On transcranial Doppler, cerebral circulatory arrest is indicated by flow patterns without forward flow progress, progressing from decrease in diastolic flow to disappearance of diastolic flow to oscillating pattern with retrograde flow in diastole, short systolic spikes, and finally absence of Doppler signal. AAN has included neuroimaging explaining coma as one of their prerequisite to be checked before evaluation for BD. Thus, a radiologist can play a critical role by recognizing the initial extensive hypoxic or ischemic damage to the central nervous system including the brainstem on imaging; guiding a neurologist evaluating a potential BD, as well as ruling out other pitfalls. In many cases, the radiologist is often the first person to appreciate the devastating findings of irreversible brain damage. Three most common mimics of BD are hypothermia, locked-in syndrome, and drug intoxication. By judicious usage of the available ancillary tests, cautiously interpreting the findings with awareness of their limitations and pitfalls, a radiologist can provide the support needed to confirm BD.

Time-delayed contrast-enhanced MRI improves detection of brain metastases: a prospective validation of diagnostic yield.

The radiological detection of brain metastases (BMs) is essential for optimizing a patient's treatment. This statement is even more valid when stereotactic radiosurgery, a noninvasive image guided treatment that can target BM as small as 1-2 mm, is delivered as part of that care. The timing of image acquisition after contrast administration can influence the diagnostic sensitivity of contrast enhanced magnetic resonance imaging (MRI) for BM. Investigate the effect of time delayed acquisition after administration of intravenous Gadavist® (Gadobutrol 1 mmol/ml) on the detection of BM. This is a prospective IRB approved study of 50 patients with BM who underwent post-contrast MRI sequences after injection of 0.1 mmol/kg Gadavist® as part of clinical care (time-t0), followed by axial T1 sequences after a 10 min (time-t1) and 20 min delay (time-t2). MRI studies were blindly compared by three neuroradiologists. Single measure intraclass correlation coefficients were very high (0.914, 0.904 and 0.905 for time-t0, time-t1 and time-t2 respectively), corresponding to a reliable inter-observer correlation. The delayed MRI at time-t2 delayed sequences showed a significant and consistently higher diagnostic sensitivity for BM by every participating neuroradiologist and for the entire cohort (p = 0.016, 0.035 and 0.034 respectively). A disproportionately high representation of BM detected on the delayed studies was located within posterior circulation territories (compared to predictions based on tissue volume and blood-flow volumes). Considering the safe and potentially high yield nature of delayed MRI sequences, it should supplement the standard MRI sequences in all patients in need of precise delineation of their intracranial disease.

Hemifacial spasm due to vertebrobasilar dolichoectasia: a case report.

Hemifacial spasm (HFS) happens because of vascular compression of the facial nerve at the root exit zone. Vertebrobasilar dolichoectasia (VBD) is a very rare cause of HFS. VBD is diagnosed by computed tomography angiography and magnetic resonance imaging. Here, we report a case of 65-year-old female patient with HFS due to VBD. We discuss the complications and the treatment options for the case.

Indium-111 Capromab Pendetide (ProstaScint(®)) Demonstrates Renal Cell Carcinoma and Aortocaval Nodal Metastases from Prostate Adenocarcinoma.

A 62-year-old male with a history of radical prostatectomy for a Gleason 9 (4 + 5) pT3N0Mx prostate cancer presented with rising prostate-specific antigen of 9.0 ng/dl. A contrast-enhanced computerized tomography (CT) revealed an enhancing left upper pole renal mass and aortocaval lymph nodes. Indium (In)-111 Capromab Pendetide (ProstaScint(®)) single-photon emission computerized tomography-CT showed abnormal increased uptake in left renal mass and aortocaval lymph nodes with no uptake in the prostate bed or pelvic lymph nodes. He underwent left radical nephrectomy and dissection of aortocaval lymph nodes. Pathology showed renal clear cell carcinoma and metastatic prostate adenocarcinoma involving aortocaval lymph nodes. Our case demonstrates a rare combination of two different malignancies, prostate cancer and clear cell renal cell cancer, showing In-111 ProstaScint(®) uptake. Though ProstaScint(®) uptake in renal cell carcinoma and in metastatic aortocaval lymph nodes from prostate cancer may be seen in clinical practice, this combination has not been reported previously.

Complex aortic arch anomaly: Right aortic arch with aberrant left subclavian artery, fenestrated proximal right and duplicated proximal left vertebral arteries-CT angiography findings and review of the literature.

Congenital aortic arch and vertebral artery anomalies are a relatively rare finding discovered on imaging either incidentally or for evaluation of entities like dysphagia or subclavian steal. Right aortic arch is an uncommon anatomical anomaly that occurs in less than 0.1% of the population, and in half of these cases the left subclavian artery is also aberrant.(1) Unilateral vertebral artery (VA) duplication is rare with an observed prevalence of 0.72% in cadavers.(2) Fenestration of the VA is more common than duplication, with a prevalence of approximately 0.23%-1.95%.(3,4) We describe the case of a 25-year-old female who was found to have a right aortic arch with aberrant left subclavian artery, duplicated left vertebral artery and a fenestrated right vertebral artery on CT angiography performed for evaluation of dysphagia. This combination of findings has not been reported before, to the best of our knowledge. We review the embryologic mechanism for the development of the normal aortic arch, right aortic arch, vertebral artery duplication and vertebral artery fenestration. The incidence of these entities, resultant symptoms and clinical implications are also reviewed. The increased associated incidence of aneurysm formation, dissection, arteriovenous malformations and thromboembolic events with fenestration is also discussed.

Recombinant human thyrotropin use resulting in ovarian hyperstimulation: an unusual side effect.

A 43-year-old female was administered recombinant human thyrotropin-α (Thyrogen®; Genzyme Corp., Cambridge, Mass., USA) before a fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) scan as part of an evaluation of thyroid cancer recurrence. She was administered two doses of Thyrogen only 4 weeks before for stimulated thyroglobulin measurement. The PET/CT scan demonstrated enlarged ovaries which on subsequent conservative follow-up resolved. This transient hyperstimulated state of the ovaries was presumed to be related to Thyrogen injections received twice within a space of a month. Thyrogen is being increasingly used for raising the level of thyroid-stimulating hormone (TSH), besides thyroid hormone withdrawal for suspected recurrence of differentiated thyroid carcinoma. Ovarian hyperstimulation has been reported as an iatrogenic complication for in vitro fertilization with the presence of human chorionic gonadotropin being invariably associated. Transient gestational thyrotoxicosis has been reported to be related to promiscuous activation of the thyrotropin receptor by chorionic gonadotropin. In our case it is possible that due to the promiscuous stimulation, thyrotropin caused a follicle-stimulating hormone (FSH)-like action resulting in ovarian hyperstimulation. The reason behind this could be the shared sequence identity of the hormone-binding domains of TSH and FSH receptors, or some mutation in the FSH receptor. In conclusion, our case highlights a potential side effect of administering Thyrogen in females of the reproductive age group.

Penile necrosis due to calciphylaxis in a patient of end stage renal disease.

A case of a 72-year-old diabetic, hypertensive male with end stage renal disease as a result of the underlying condition of calciphylaxis, presenting with gangrene of the glans penis is reported. In calciphylaxis, calcification of small and medium-sized arteries occurs, which may result in ischemia and gangrene. A computed tomography scan of the lower abdomen, pelvis, and the upper thigh was performed, which showed diffuse and extensive calcification of the walls of the small and medium-sized arteries, with almost complete obliteration of the lumen of the small arteries. A 3-dimensional reconstruction of the penis using volume rendering technique, demonstrated the ulceration of the glans penis in an exquisite manner. The appearance is so peculiar that no histological confirmation is needed. A review of relevant literature related to the etiopathogenesis, radiological findings, treatment, and prognosis is also discussed.

Metachronous double spinal dural arteriovenous fistulas. Case report and review of the literature.

Spinal dural arteriovenous fistulas (DAVFs), the most common of spinal vascular malformations, are AVFs in the dura mater of the nerve root and/or adjacent spinal dura. These fistulas are most often solitary and are fed by a single radicular artery that primarily supplies the dura mater. Multiple spinal DAVFs are rarely reported in the literature. Those that have been documented have been synchronous in their presentation in that they were found during the same examination or were present at the initial examination but missed and only recognized at the second examination. The authors report the case of a patient with two spinal DAVFs occurring at different spinal levels at different points in time (metachronous).

Postangiographic thrombosis of a spinal arteriovenous malformation: case report.

The authors report the case of a 30-year-old man who presented with progressive neurological deficits due to a spinal arteriovenous malformation (AVM). There was sudden increase in his neurological deficits after diagnostic angiography was performed. Repeated magnetic resonance imaging and angiography revealed complete thrombosis of the malformation. Stenosis in the draining vein was the most probable cause of this postangiographic occlusion of the AVM. Contrast injection during angiography may have precipitated the thrombosis.