Vibhute, Prasanna

Background Transvenous embolization is emerging as a promising treatment for cerebrospinal fluid-venous fistulas (CVF) associated with spontaneous intracranial hypotension (SIH). Objective To perform an independent validation of the efficacy and safety of the procedure and describe the procedural techniques used at our institution. Methods A retrospective review was performed including consecutive patients with SIH who had undergone CVF embolization with 3-month clinical and imaging follow-up. Clinical evaluation included the Patient Global Impression of Change (PGIC) Scale and six-item Headache Impact Test (HIT-6). Bern SIH score was used for imaging evaluation on brain MRI. Post-treatment changes in scores were assessed by Wilcoxon signed rank test. Procedural technical details, including use of upper-extremity access and dual-microcatheter pressure cooker technique, were recorded. Results 18 patients (13 female, median age 60 years) were included. 17 (94%) procedures were performed with upper-extremity access and 12 (67%) using dual-microcatheter pressure cooker technique. After embolization, 16 (89%) patients reported much or very much improved at follow-up PGIC; median (IQR) HIT-6 score improved from 68 (62–72) to 36 (36–38) and Bern SIH score improved from 8 (6–8) to 3 (1.5–3.5), p values <0.001. Side effects were transient embolization site back pain in 15 (83%) and rebound intracranial hypertension requiring medical management in 9 (50%) patients. HIT-6 and Bern SIH score changes were similar between conventional and pressure cooker techniques ( p values >0.05). Conclusion Transvenous embolization is independently validated as a highly effective and safe treatment for CVF and is feasible using upper-extremity venous access. Dual-microcatheter and balloon/coil pressure cooker techniques may be used to optimize distribution of embolic material and potentially, treatment efficacy.

Abstract Purpose Spinal extradural arachnoid cysts (SEDAC) are thought to arise from leakage of CSF through a spinal dural defect. This study investigates the demographics and imaging spectrum of SEDACs at our academic institution and compares them with those reported in the literature. Material and Methods Fifty cases with documented MRI diagnosis of SEDAC, Nabors criteria type I meningeal cyst (MC), were identified from retrospective review of imaging records between 1999 to 2020. Patient demographics, presenting symptoms, cyst characteristics, and management outcomes studied. Statistical analysis to determine associations between maximum cyst size and presenting symptoms along with other imaging findings. Results In all 50 subjects, SEDACs were solitary (single) and sporadic (non-familial). The majority were incidental (62%), located posteriorly (92%) and laterally (80%) in the thoracic and thoracolumbar regions (34%, 30%). They were associated with mild mass effect upon the thecal sac (50%) and bone remodeling (92%). Among symptomatic SEDACs, back pain and radiculopathy were the most reported (68%). Larger cysts were located caudally in the spinal canal, and were associated with greater thecal mass effect, bone remodeling, and septations. Four out of six subjects who underwent surgical management had complete or partial remission. One had cyst recurrence. Conclusion In this largest series of SEDACs, most were discovered incidentally, stable over time, and located in the thoracic spine dorsal to the thecal sac. When symptomatic, back pain and radiculopathy were the most common presenting symptoms. Treatment with complete surgical excision may yield the best results for symptomatic lesions.

Purpose Cartilage cap resurfacing is a method to seal a superior semicircular canal dehiscence. The purpose of this study was to evaluate the detection of new bone formation after surgical placement of a cartilage cap over a dehiscent semicircular canal. Methods In this retrospective review, two neuroradiologists blinded to each other’s interpretation reviewed the temporal bones of 20 patients, five of which had a pre-operative computed tomography (CT) exam which was interpreted as unilateral superior semicircular canal dehiscence and with new bone formation following repair on follow-up CT. There were also 15 control subjects. Each neuroradiologist was blinded to history, including post-operative changes, and asked to determine if there was a dehiscence or no dehiscence. Results Out of the 15 controls, there was 100% inter-observer agreement. On the five post-operative patients, there was agreement in 4/5 that there was no dehiscence post-operatively and 1/5 agreement of dehiscence post-operatively, but ectopic bone adjacent to the dehiscence. Conclusion Our results indicate that new bone formation can be seen at the site of cartilage cap placement over the dehiscence and be interpreted as bony closure of the dehiscence.

AbstractPrior studies suggest high prevalence of intracranial aneurysms (IA) in patients with infrarenal abdominal aortic aneurysms (AAA). We reviewed our multicenter experience in clinical detection/treatment of IAs in AAA patients and estimated the risk of IA in patients with AAA relative to patients without AAA. We reviewed cases of vascular surgery infrarenal AAA repairs at three Mayo Clinic sites from January 1998 to December 2018. Concurrent controls were randomly matched in a 1:1 ratio by age, sex, smoking history, and head imaging characteristics. Conditional logistic regression was used to calculate odds ratios. We reviewed 2,300 infrarenal AAA repairs. Mean size of AAA at repair was 56.9 ± 11.4 mm; mean age at repair, 75.8 ± 8.0 years. 87.5% of the cases (n = 2014) were men. Head imaging was available in 421 patients. Thirty-seven patients were found to have 45 IAs for a prevalence of 8.8%. Mean size of IA was 4.6 ± 3.5 mm; mean age at IA detection, 72.0 ± 10.8 years. Thirty (81%) out of 37 patients were men. Six patients underwent treatment for IA: four for ruptured IAs and two for unruptured IAs. All were diagnosed before AAA repair. Treatment included five clippings and one coil-assisted stenting. Time from IA diagnosis to AAA repair was 16.4 ± 11.0 years. Two of these patients presented with ruptured AAA, one with successful repair and a second one that resulted in death. Odds of IA were higher for patients with AAA versus those without AAA (8.8% [37/421] vs. 3.1% [13/421]; OR 3.18; 95% confidence interval, 1.62–6.27, p < 0.001). Co-prevalence of IA among patients with AAA was 8.8% and is more than three times the rate seen in patients without AAA. All IAs were diagnosed prior to AAA repair. Surveillance for AAA after IA treatment could have prevented two AAA ruptures and one death.

AbstractIntroduction Vestibular schwannomas (VS) are slow growing tumors. Although there are a wide variety of available treatment options, these tumors are often initially observed. We aimed to establish the presenting symptoms and outcomes of patients treated with initial observation at our institution.Methods The medical records of patients with radiographically diagnosed VS were reviewed from 1989 to 2018. Actuarial estimates of radiographic tumor control and freedom of local therapy were calculated and compared using Cox regression analyses.Results A total of 360 patients were diagnosed with VS at our institution from 1989 through 2018 with a median age of 59.9 years. After radiographic diagnosis, 243 patients (67.5%) opted for initial observation. Local control at 1, 5, and 10 years was 91, 67, and 58%, respectively. On multivariable analysis, factors associated with shorter time to radiographic tumor progression included younger patient age (p = 0.016) and tumors with an extracanalicular component (p = 0.032). Regarding time until definitive treatment only larger baseline American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) tumor size predicted for earlier initiation of therapy (p < 0.001), although this was restricted to tumors with an extracanalicular component (p = 0.004), as opposed to purely internal auditory canal tumors (p = 0.839).Conclusion Many patients who were initially observed continued to have satisfactory local control rates at 10 years. In patients with extracanalicular tumors, larger AAO-HNS tumor measurements were associated with earlier radiographic tumor progression and shorter time to local therapy, with 7 mm serving as a potential threshold value for extracanalicular tumors. Younger patients and tumors with primarily an extracanalicular portion may warrant closer observation.

OBJECTIVEThe role of CT perfusion (CTP) in the management of patients with acute ischemic stroke (AIS) remains a matter of debate. The primary aim of this study was to evaluate the correlation between the areas of infarction and penumbra on CTP scans and functional outcome in patients with AIS.METHODSThis was a retrospective review of 100 consecutively treated patients with acute anterior circulation ischemic stroke who underwent CT angiography (CTA) and CTP at admission between February 2011 and October 2014. On CTP, the volume of ischemic core and penumbra was measured using the Alberta Stroke Program Early CT Score (ASPECTS). CTA findings were also noted, including the site of occlusion and regional leptomeningeal collateral (rLMC) score. Functional outcome was defined by modified Rankin Scale (mRS) score obtained at discharge. Associations of CTP and CTA parameters with mRS scores at discharge were assessed using multivariable proportional odds logistic regression models.RESULTSThe median age was 67 years (range 19–95 years), and the median NIH Stroke Scale score was 16 (range 2–35). In a multivariable analysis adjusting for potential confounding variables, having an infarct on CTP scans in the following regions was associated with a worse mRS score at discharge: insula ribbon (p = 0.043), perisylvian fissure (p < 0.001), motor strip (p = 0.007), M2 (p < 0.001), and M5 (p = 0.023). A worse mRS score at discharge was more common in patients with a greater volume of infarct core (p = 0.024) and less common in patients with a greater rLMC score (p = 0.004).CONCLUSIONSThe results of this study provide evidence that several CTP parameters are independent predictors of functional outcome in patients with AIS and have potential to identify those patients most likely to benefit from reperfusion therapy in the treatment of AIS.

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 <0.001) and deep WMH (r=0.47, p <0.001). However, collateral scores exhibited no statistically significant relationship with the presence or severity of periventricular scores (r=0.08, p=0.17) or deep WMH scores (r=0.01, p=0.77). 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: 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<0.05. 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.