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Background Epidural venous congestion secondary to inferior vena cava (IVC) stenosis is a well-documented cause of low back pain and radiculopathy secondary to compressive effects from the epidural veins, decreased tissue perfusion, and resultant ischemia. Methods Single patient case report. Case description We report a unique case of a 62-year-old male with low back pain secondary to IVC stenosis from a chronically occluded IVC filter. The patient's pain resolved with endovascular removal of the occluded filter and recanalization of the IVC. Conclusion We demonstrated that by treating the underlying cause of secondary epidural venous engorgement (occluded IVC filter in this case), the patient experienced resolution of back pain and radiculopathy.

Abusive head trauma (AHT) is the leading cause of fatal head injuries in children younger than 2 years. An intracranial pathology can exist even in the setting of a normal physical exam. A delay in the diagnosis of AHT can have serious life-threatening consequences for the child and increases the potential the child will be abused again. In this article, we review the traumatic subdural hematoma as well as various morpho-structural patterns of shearing injuries and thrombosis of intracranial bridging veins. This work serves as a summary of patterns of imaging features of intracranial venous injury in AHT, as described in the literature, to facilitate familiarity and early detection of abusive head trauma in the pediatric population. Essentially, in AHT there is a traumatic injury to the bridging vein with either partial or complete tear. This can secondarily result in thrombosis at the terminal end of the bridging vein with blood clots adjacent to the bridging vein.

Human immunodeficiency virus (HIV)-vacuolar myelopathy is a late presentation of HIV infection and rarely the presenting symptom. Treatment of HIV-vacuolar myelopathy involves anti-retroviral therapy, but neurological deficits are devastating if diagnosis is delayed. We present a rare case of a patient who presented with HIV-vacuolar myelopathy as the initial presentation in a case of newly diagnosed HIV. The case emphasizes the importance of a high index of suspicion and diagnosis for better outcomes in HIV-vacuolar myelopathy.

Diagnosis of skull base infections (SBI) is challenging to the radiologist because of the vague and non-localizing presentations of this entity that often result in serious intracranial complications with fatal outcome. Subtle and early imaging findings may occasionally be neglected even by the experienced radiologist. Therefore, high index of suspicion, knowledge of anatomy of the paranasal sinus and petromastoid complex, and systematic scrutiny of appropriately timed imaging exams are extremely valuable in early diagnosis and treatment of SBI. This article reviews relevant anatomy, imaging clues for early diagnosis, pattern of spread, and complications of SBI as related to the paranasal sinuses. Keywords: Skull base infection, Bacterial sinusitis, Fungal sinusitis, Paranasal sinus, Petromastoid complex, Osteomyelitis

Ectopic pituitary adenomas (EPA) are rare tumors thought to arise from embryological remnants along the route of normal pituitary migration. Clinically, these tumors vary in hormonal activity and can exert mass effect based on location and size. We performed a single-center retrospective analysis of patients with diagnosis of ectopic pituitary adenoma from 2001 to 2018. Five patients were identified with EPA: a 48-year-old woman with suprasellar EPA treated with transsphenoidal removal of the tumor, a 44-year-old woman with cavernous EPA treated with transsphenoidal removal of the tumor, a 48-year-old woman with sphenoid EPA treated with cabergoline, a 45-year-old man with clival EPA treated with cabergoline and transsphenoidal surgical resection, and a 54-year-old man with clival EPA treated with cabergoline therapy. EPA should be considered as a differential diagnosis of juxta-sellar lesions. Appropriate hormonal testing may lead to early diagnosis, avoidance of unnecessary biopsy or surgery, and improved outcomes.

Given the substantial heterogeneity of stroke brain injury, there is a clear need for a biomarker that determines the degree of neuroaxonal injury across diverse stroke types. We evaluated whether blood neurofilament light (NFL), a major component of neuronal axons, would fulfill this purpose for patients with acute cerebral infarction (ACI, N=227), aneurysmal subarachnoid hemorrhage (aSAH, N=58) or non-traumatic intracerebral hemorrhage (ICH, N=29). We additionally validated our findings in two independent cohorts of patients with ICH (N=96 and N=54) given the scarcity of blood biomarker studies for this deadliest stroke type. Compared to healthy individuals (N=79 and 48 for the discovery and validation cohorts, respectively), NFL was higher for all stroke types. NFL associated with radiographic markers of brain tissue damage. It correlated with the extent of early ischemic injury in patients with ACI, hemorrhage severity in patients with aSAH, and intracranial hemorrhage volume in patients with ICH. In all patients, NFL independently correlated with scores from the NIH Stroke Scale, the modified Rankin Scale, and the Mini-Mental State Examination at blood draw, which respectively assess neurological, functional, and cognitive status. Furthermore, higher NFL concentrations independently associated with 3- or 6-month functional disability and higher all-cause mortality. These data support NFL as a uniform method to estimate neuroaxonal injury and forecast mortality regardless of stroke mechanism. As a prognostic biomarker, blood NFL has the potential to assist with planning supportive and rehabilitation services, and improving the efficiency of acute therapeutic drug and device trials, and of recovery trials.

The neuroradiology fellowship match is conducted by the National Resident Matching Program (NRMP) every year. The purpose of this study is to report the trends in neuroradiology match results from 2008 to 2020 in the United States (US) using data available from the NRMP. The fellowship match data was obtained from the NRMP archives. Data specific to programs (number of programs and filled positions) were obtained. Using the NRMP's “Charting Outcomes in the Match: Specialty Matching Service'' report, a detailed analysis of applicant characteristics broken down for each specialty, was also obtained for neuroradiology for the year 2018. Neuroradiology programs in the NRMP Match increased from 71 to 77 and the number of positions increased from 158 to 270 between 2008 and 2020. The fill rate of fellowship spots has remained steady at 75.9% in 2008 and 74.4% in 2020. The proportion of US allopathic medical graduates (US MD) amongst the filled spots decreased from 79.2% (2008) to 64.2% (2020), while the proportion of international medical graduates (IMGs) increased from 11.7% to 25.4%. US MD and IMG fill trends did not reach statistical significance (P = 0.78 and P = 0.92, respectively). US MDs had a higher number of research experiences and publications (23.2 and 26, respectively) when compared to US IMGs (5 and 7) and non-US IMGs (6.8 and 14.2). To conclude, over the last 13 years, the neuroradiology fellowship programs in the US have increased in number and expanded in size, with an almost stable fill rate of around 75%.

To analyze the trends in international medical graduates (IMGs) matching into diagnostic radiology residency programs in the United States (US).The National Resident Match Program data was accessed for years 2005-2020 and diagnostic radiology residency-specific data was extracted for US MD, osteopathic (DO), and IMG applicants. IMGs were categorized into US-citizen IMGs and non-US citizen IMGs per the National Residency Match Program. Variables collected for each year included the number of positions, number of applicants in each group, positions filled/unfilled, and fill rate of each group. Additional data for some years included USMLE Step 1 score, United States Medical Licensing Examination (USMLE) Step 2 clinical knowledge (CK) score, number of research experiences, number of abstracts/publications, and additional degrees obtained. Trends were analyzed using simple linear regression model and p value0.05 was considered significant.The number of diagnostic radiology residency programs increased from 203 (2006) to 212 (2020). The total number of diagnostic radiology residency positions increased from 1011 (2006) to 1113 (2020), with the peak of 1145 in 2014. The overall "match rate," that is, proportion of positions filled to positions available, increased from 96.4% (2006) to 97.3% (2020), with a brief decline to 86.7% in 2015. Among the filled positions, the proportion filled by US medical school graduates significantly declined from 89.7% (2006) to 69.2% (2020) (p0.001), and the proportion of positions filled by osteopathic seniors and graduates significantly increased from 2.2% (2006) to 15.1% (2020; p0.001). The proportion of US IMGs increased from 3.2% (2006) to 5.4% (2020), while the proportion of non-US IMGs increased from 4.4% (2006) to 9.4% (2020), with overall IMG match rate increased significantly from 7.6% to 14.9% (p = 0.009). The mean Step 1 scores of US IMGs and non-US IMGs were 238 and 237.3, and the mean Step 2 CK scores were 241.67 and 241, respectively. Cumulatively over the study period, a total of 736 US IMGs and 1051 non-US IMGs have matched into diagnostic radiology residency.There is an increasing proportion of IMGs, especially the non-US citizen IMGs, matching into US radiology residency programs in the last decade. Diagnostic radiology remains a competitive specialty evidenced by average USMLE scores higher than national average and research experiences of matched candidates.

Objective Syrinx development in patients with spontaneous intracranial hypotension (SIH) has rarely been described. To better understand this entity, we compared the clinical and radiographic findings in a series of patients with SIH and acquired Chiari-like tonsillar herniation with and without syrinx formation. Methods Six patients with syrinx in the setting of SIH and Chiari-like tonsillar herniation were retrospectively identified. The clinical and radiographic findings and outcomes were compared with those from a control group of patients with SIH and Chiari-like tonsillar herniation without syrinx. Results The patients with SIH and syrinx had had a higher opening pressure than had the control group (mean, 14.0 cm H2O vs. 7.4 cm H2O; P = 0.02) and a higher body mass index (mean, 33 kg/m2 vs. 26 kg/m2; P = 0.01). The patients with syrinx had had an average obex displacement of 3.7 ± 2.2 mm below the plane of the foramen magnum compared with a position of 1.9 ± 3.1 mm above the plane of the foramen magnum in the control group (P = 0.004). The mean tonsillar descent was 12.7 ± 4.7 mm below the foramen magnum in those with syrinx compared with 5.9 ± 2.5 in the control group (P = 0.009). The clinical symptoms had improved in 83.3% of the patients with syrinx and 75% of the control patients after spinal cerebrospinal fluid leak closure. Three patients (50%) also had radiographic syrinx reduction. Conclusion Our results have shown that SIH can be an underrecognized cause of syrinx with key differences in body habitus and obex displacement compared with SIH without syrinx. In patients with tonsillar herniation into the foramen magnum associated with syrinx, the presence of SIH should be considered to avoid unnecessary foramen magnum decompression, even in those with a normal opening pressure.

Objective To investigate the accessibility and content of interventional neuroradiology (INR) fellowship program websites in North America. Methods We obtained a list of INR/endovascular surgical neuroradiology (ESN) fellowship programs from the Accreditation Council for Graduate Medical Education, the Committee on Advanced Subspecialty Training, the Society of NeuroInterventional Surgery, and the Neurosurgical Fellowship Training Program Directory websites. Individual program websites were evaluated for 27 different fellow recruitment and education criteria. U.S. programs were grouped based on census region and national ranking, and differences between these groups with regard to fellow recruitment and education characteristics were analyzed using nonparametric statistics. Results A total of 79 INR/ESN fellowship websites were evaluated for presence of fellow recruitment and education features. Approximately one third of all features pertinent to recruitment (32.11%) and approximately 1 in 5 features regarding education (19.11%) were described in these websites. Program description (69.6%), program coordinator/administrator contact e-mail (59.5%), program director's name (59.5%), program eligibility requirements (51.9%), research opportunities (40.5%), and faculty listing (39.2%) were among the most frequently described features, whereas details about parking (1.3%), interview day itinerary (1.3%), meal allowance (2.5%), retirement and benefits (3.8%), and call schedule (5.1%) were the least frequently described features. There was no significant difference between surveyed features and programs when stratified by U.S. census region, neurosurgery/neurology hospital rankings, or accreditation status. Conclusions INR/ESN fellowship website content is variable across North America and there is room for improvement to develop and enhance comprehensiveness of program website content.

Pediatric interventional radiology has grown as an advanced subspecialty with increased demand, number and complexity of cases, and number of pediatric institutions offering a pediatric interventional radiology service. Despite the overall increase in the number of pediatric interventionalists over the past two decades, there is a heterogeneity in their academic backgrounds and a lack of uniform training pathways. To analyze the demographics, academic backgrounds and scholarly activities of pediatric interventionalists across the United States (U.S.) and Canada. A list of all members of the Society for Pediatric Interventional Radiology was obtained and pediatric interventionalists at academic and private practice institutions in the U.S. and Canada were included. Publicly available online sources were used to gather demographic and educational information about each pediatric interventionalist, which included the online curriculum vitae, the HealthGrades.com and Doximity.com websites, and Elsevier’s Scopus database. Demographic and educational data including age, gender, educational background, additional degrees, academic rank, previous leadership positions, and metrics of scholarly activities were recorded. Fellowships in diagnostic pediatric radiology, adult interventional radiology and/or pediatric interventional radiology were recorded. Mann-Whitney U tests and Kruskal-Wallis tests were used to compare differences between groups. One hundred and twenty-five pediatric interventionalists were included, of whom 24 (19.2%) were female. The mean age was 48.6 years (standard deviation [SD]: 10.6, median: 45 years, range: 36–82 years). There was no statistical difference between median age for male versus female pediatric interventionalists (44.5 years vs. 45 years, P=0.89). A majority of pediatric interventionalists were American medical school graduates (96, 76.8%), while 29 (23.2%) were international medical graduates. Eighty-three percent (104) of the pediatric interventionalists completed diagnostic radiology residency training in the U.S., most commonly at the University of Cincinnati in Ohio (6.4%) and Washington University in St. Louis, MO (5.6%). Among fellowship training, pediatric interventionalists completed a pediatric radiology fellowship (61.6%), adult interventional radiology fellowship (40%) and/or a dedicated pediatric interventional radiology fellowship (57.6%). The mean±SD (median) publications, citations and Hirsch index (h-index) for pediatric interventionalists were 32±45 (12), 68±1,317 (120) and 9±10 (5), respectively. There was a statistically higher number of publications, citations and h-index with increasing academic rank at the assistant, associate and professor levels (P

Purpose To analyse the demographics, academic background, and scholarly activity of Interventional Neuroradiology (INR)/Endovascular Surgical Neuroradiology (ESN) program directors (PDs) in the United States (US) and Canada. Methods A list of all INR/ESN fellowships was obtained from the Accreditation Council for Graduate Medical Education, the Committee on Advanced Subspecialty Training, maintained by Society of Neurological Surgeons, the NeuroInterventional Training list website maintained by the Society of NeuroInterventional Surgery, and the Neurosurgical Fellowship Training Program Directory website maintained by the American Association of Neurological Surgeons. Online search was performed to identify PDs for these programs. Publicly available sources used to gather information about each PD included the program websites, the HealthGrades and Doximity websites, and Elsevier's Scopus database. Demographic and educational data including age, gender, educational background, subspecialty, appointment age, interval between residency completion and appointment as PD, additional degrees, academic rank, prior leadership positions, and metrics of scholarly activity were recorded. One-way analysis of variance was used to determine differences between the means of different groups. Results A total of 78 PDs from 72 programs were included, of which 72 (92.3%) were male with the mean age of 49.59 years (SD 7.25). Specialty division of PDs was neurosurgery (40, 51.3%), radiology (26, 33.3%), and neurology (10, 12.8%), whereas 2 PDs were dual board-certified in neurology and radiology. Twenty-five (32.1%) PDs attended an international medical school. All PDs received an MD degree or foreign equivalent, with no PD holding a DO degree. Eleven PDs received a PhD degree and 16 PDs received fellowship from a professional medical society. The mean ± SD publications, citations, and h-indexes of PDs were 111.32 ± 121.18, 2985.0 ± 1459.0 and 22.27 ± 15.45, respectively. There was no statistical difference in scholarly activity among PDs when stratified on the basis of specialty, gender, and US region. Conclusion INR/ESN PDs are predominantly male, with a majority from neurosurgery background, and thirty percent having graduated from international medical schools.

Objective First-line treatment for prolactin-producing pituitary adenomas is dopamine agonist (DA) therapy. This is the first study to analyze the rate of radiographic and hormonal regression of prolactinomas in response to DA therapy to better understand what time frame we consider DA treatment failure. Methods We searched the electronic medical records of 3 tertiary care medical institutions for patients with prolactinomas. The primary outcome was tumor volume and prolactin (PRL) levels at various time points. The secondary outcome was indicators of treatment failure. Modeling by both linear and exponential models was tested to determine potential predictors of response magnitude and treatment failure by multivariate and regression analyses respectively. Results There were 99 patients (53% male) included in this analysis. The mean patient age was 42.7 years ± 14.5, and mean width/volume of tumor at diagnosis was 12.3 mm and 1.3 cm3, respectively. The mean PRL level at diagnosis was 593.2 ng/mL (79–7913). Modeling indicated a plateau at 68.2% initial volume (95% confidence interval 61.7–73.5) by 12.6 months and a PRL plateau of 21.4 ng/mL (95% confidence interval 0–92.5) by 3.3 months. Multivariate analyses revealed male sex (odds ratio 0.168; P = 0.036) to be a predictor of faster PRL response to DA therapy. Conclusions Prolactinomas plateau in PRL levels and the rate of size regression within the first year of DA treatment. Prolactinomas with lack of size regression and failure to reach normalization of PRL levels by 12 months may be considered for other management strategies.

We read with interest the study by Lehtola et al.1 Anticoagulation (AC) in atrial fibrillation (AF) reduces the risk of ischemic stroke, but at the cost of increasing the risk of hemorrhagic stroke.

Introduction: Poor leptomeningeal collateral flow is related to worse neurological outcome in acute ischemic stroke. The increased release of stress hormones during the first hours of acute stroke leads to inhibition of insulin secretion and increase insulin resistance, thus inducing stress hyperglycemia, which is often evident on blood glucose levels at admission. While admission hyperglycemia, independent of diabetes mellitus (DM) is associated with poor clinical outcome in ischemic stroke, studies on its effect on collateral circulation after acute cerebral embolism are largely inconclusive. Methods: We identified a consecutive series of patients aged 18 years and older from 2008 to 2018 with acute embolic large vessel stroke confirmed on CT angiography (CTA) using an institutional database. Individual CTAs were over-read, and collateral scores of the affected hemisphere were calculated using a modification of the Tan scale (0-4), by two trained readers. We reviewed the electronic medical records for presenting NIHSS, admission glucose and HbA1C levels, and prior history of DM. Spearman’s ρ, odds ratios (OR), and their 95% confidence intervals (CI) were analyzed. All tests were considered significant when P Results: Of the 405 patients identified through the database (mean age 70 years [range, 55-85], 45% [183/405] women), 35% (142/405) had a prior history of DM. Mean admission glucose was 134±51 mg/dL, and median NIHSS at presentation was 17. Blood glucose level at admission was negatively correlated with collateral scores (ρ= -0.23, P=0.008). Specifically, glucose levels above 120 mg/dL were significantly associated (OR 1.68 CI 1.13-2.5) with poor collateral scores (≤1). However, collateral scores exhibited no statistically significant relationship with HbA1c (ρ=-0.08, P=0.15) or prior history of DM (P=0.73). Conclusions: Patients with higher admission glucose levels have poor collateral scores, while HbA1c and prior DM do not have a similar effect on collateral flow. Our results suggest that poor collateral flow may explain adverse outcomes associated with hyperglycemia in acute ischemic stroke. Determining if there is a benefit of aggressive glycemic control within the first few hours of embolic stroke warrants further study.

Introduction: White matter hyperintensities (WMH) is the most prominent neuroimaging feature of small vessel disease (SVD). SVD is thought to be a result of arteriolosclerosis, chronic hypoperfusion of white matter, selective oligodendrocyte death and degeneration of myelinated fibers. The risk of ischemic stroke is significantly increased with the presence of WMH. The presence of intracranial collaterals is a strong predictor of salvageable neurological function in acute stroke; however, the factors affecting the ability to recruit collaterals are poorly understood. We wanted to study if the presence and severity of small vessel white matter disease had an adverse effect on cerebral collateral flow in acute embolic large vessel stroke. Methods: We identified a consecutive series of adult subjects with acute embolic large vessel strokes confirmed on CT angiography (CTA) from a 10-year institutional database. Patients without a brain MRI within six months of CTA were excluded. Collateral scores of the affected hemisphere were calculated on CTA using the modified Tan scale (0-4) by two independent trained reviewers and confirmed by a neuroradiologist. The WMH was quantified using the Fazekas scale (0-3) incorporating both deep and periventricular components. Areas of restricted diffusion on brain MRI in the peri-stroke period were eliminated from the assessment of Fazekas score. Spearman’s correlation tests were performed for the association between collateral scores and WMH. Results: A total of 234 patients (mean age 70±14 years, 47% [110/234] women) satisfied the inclusion criteria. The prevalence of periventricular and deep WMH was 83% and 87% respectively. Aging had a significant impact on periventricular WMH (r=0.48, p p Conclusions: Our results indicate that the presence of SVD does not affect cerebral collateral flow. The vascular niche and risk factors of SVD appear to be distinct from that of intracranial vessels responsible for collateral reperfusion of ischemic territory in acute large vessel embolic stroke.

Introduction: Good collateral flow is associated with improved outcomes in acute embolic stroke. There is compelling data linking smoking to all types of stroke, with current smokers at a higher risk than former or never smokers. Smoking has, however, been shown to promote collaterals in coronary vascular bed in humans. It is unknown if there is a similar effect in cerebral collateral flow. We aimed to investigate if cigarette smoking was positively associated with collateral blood flow in a homogenous cohort of patients with acute large vessel occlusive embolic stroke. Methods: We identified all patients aged ≥18 with acute ischemic stroke showing embolic occlusion of ICA terminus/M1 MCA on admission CT angiography (CTA), between 2008 to 2018, through an institutional database. Patients with chronic occlusions and stenotic lesions were excluded. Individual CTAs were independently reviewed by two trained investigators to calculate collateral scores of the affected hemisphere using the modified Tan scale (0-4) as a reference. Details of cigarette smoking history were obtained from the electronic medical records. Patients were grouped into smokers (former and current smokers) and never smokers. Odds ratios (OR) and their 95% confidence intervals (CI) were estimated, and all tests were considered significant when P Results: Of the 612 patients identified through the database, 429/612 patients (mean age 71±16 years, 45% [194/429] women) satisfied the inclusion criteria. 64.8% (278/429) had a positive history of smoking with an average of 47±12 pack-years. There was a significant association between good collateral scores (≥2) with smoking history (OR 1.74 CI 1.17-2.61, P=0.006). This trend remained significant even after comparing raw collateral scores (0-4) ( P=0.006, Spearman’s ρ=0.22). However, number of pack-years and collateral scores exhibited no statistically significant relationship (P=0.6). Conclusions: Our study shows that patients who have ever smoked have higher intracranial collateral vessel scores in the event of an acute embolic stroke. Increased impedance and reduced cerebral blood flow resulting from cigarette smoking may stimulate collateral recruitment in cerebral pial circulation, similar to the effect in coronary bed.

We read, with interest, the impressive study by Marti-Fabregas et al.1 As discussed, the HERO study and the CROMIS-2 study together have elaborated on the safety of oral anticoagulation (OA) in patients with cerebral microbleeds (CMBs).1,2

Patients with cerebral microbleeds have increased risk of intracranial hemorrhage and ischemic stroke. No trial specifically informs antithrombotic therapy for patients with cerebral microbleeds and atrial fibrillation. We investigated the safety of anticoagulation versus no anticoagulation with regard to cerebrovascular outcomes and mortality.All consecutive atrial fibrillation patients from 2015 to 2018 with MRI evidence of ≥1 cerebral microbleed at time of imaging were reviewed. Patients were treated with warfarin, direct oral anticoagulants, or neither. Primary outcome was all-cause mortality informed by National Death Registry and the composite of ischemic and hemorrhagic stroke. All statistical tests were 2-sided and significant at P.05.The median interval from patient identification until the end of electronic health record surveillance was 9.93 months (interquartile range, 2.83-19.17 months). We identified 308 atrial fibrillation patients with cerebral microbleeds; 128(41.6%) were on warfarin, 88(28.6%) on direct oral anticoagulants, and 92(29.9%) on neither. Over the surveillance interval, 87 deaths, 51 ischemic strokes, and 14 hemorrhagic strokes occurred. The estimated likelihoods of the composite stroke outcome and ischemic stroke only did not differ significantly among the 3 groups. However, patients taking direct oral anticoagulants had a significantly smaller likelihood of all-cause mortality than patients who were not anticoagulated (adjusted hazard ratio: .44[.23, .83], P=.012).In patients with coprevalent atrial fibrillation and cerebral microbleeds, we did not detect differences in subsequent ischemic stroke, hemorrhagic stroke, or both, comparing warfarin, direct oral anticoagulants, or neither. Patients treated with direct oral anticoagulants had better survival than nonanticoagulated patients.

Background Classic trigeminal neuralgia is an often debilitating condition that frequently results from vascular compression at the root entry zone of the trigeminal nerve. We report a case of dural arteriovenous fistula surrounding the trigeminal nerve from near the root entry zone extending as far ventral as the Meckel cave treated solely with Gamma Knife radiosurgery. Case Description A 71-year-old woman presented with a history of persistent attacks of right facial pain after failed conservative management. Magnetic resonance imaging of the brain demonstrated dilated vasculature in the right cerebellopontine angle, and diagnostic cerebral angiography revealed a dural arteriovenous fistula surrounding the right trigeminal nerve. Stereotactic radiosurgery using Gamma Knife was performed. At 6-month follow-up, she was symptom-free with decreased caliber of abnormal vascularity surrounding the trigeminal nerve on magnetic resonance imaging. Conclusions This case suggests that trigeminal neuralgia associated with dural arteriovenous fistula can potentially be treated with Gamma Knife radiosurgery; however, more extensive studies and long-term follow-up to evaluate vessel patency will be necessary to elucidate further the role of stereotactic radiosurgery alone in treating this entity.

Extracellular vesicles (EVs) are endogenous nanoparticles that play important roles in intercellular communication. Unmodified and engineered EVs can be utilized for therapeutic purposes. For instance, mesenchymal stem cell (MSC)-derived EVs have shown promise for tissue repair, while drug-loaded EVs have the potential to be used for cancer treatment. The liver is an ideal target for EV therapy due to the intrinsic regenerative capacity of hepatic tissue and the tropism of systemically injected nanovesicles for this organ. This review will give an overview of the potential of EV therapeutics in liver disease. Specifically, the mechanisms by which MSC-EVs induce liver repair will be covered. Moreover, the use of drug-loaded EVs for the treatment of hepatocellular carcinoma will also be discussed. Although there are several challenges associated with the clinical translation of EVs, these biological nanoparticles represent a promising new therapeutic modality for liver disease.

We read with interest the study by Can et al.1 The result that the association between aspirin use and rerupture of saccular aneurysms before treatment was intriguing.The effect of aspirin in preventing acute subarachnoid hemorrhage from intracranial aneurysm rupture is well-studied.2,3 However, with the advent of endovascular and neurosurgical procedures, the data on aspirin use and rerupture are definitively unknown.

The recent article by Saliba et al.1 confirmed the inverse relationship between cholesterol levels and risk of intracerebral hemorrhage (ICH) in one of the largest well-designed observational studies conducted. This result—the first of its kind, reporting that statin use may reduce ICH risk—is intriguing.

I read, with interest, the article by Drs. Newton and Frith,1 which demonstrated bolus water drinking as a potential first-line nonpharmacologic management for aging-related orthostatic hypotension (OH). It is also clear that one of the unbridged gaps in knowledge lies in the effective management of patients with varying etiologies of OH.