Citations

Background: Despite the well-established potent benefit of mechanical thrombectomy (MT) for large vessel occlusion (LVO) stroke, access to MT has not been studied globally. We conducted a worldwide survey of countries on 6 continents to define MT access (MTA), the disparities in MTA, and its determinants on a global scale. Methods: Our survey was conducted in 75 countries through the Mission Thrombectomy 2020+ global network between November 22, 2020, and February 28, 2021. The primary end points were the current annual MTA, MT operator availability, and MT center availability. MTA was defined as the estimated proportion of patients with LVO receiving MT in a given region annually. The availability metrics were defined as ([current MT operators×50/current annual number of estimated thrombectomy-eligible LVOs]×100 = MT operator availability) and ([current MT centers×150/current annual number of estimated thrombectomy-eligible LVOs]×100= MT center availability). The metrics used optimal MT volume per operator as 50 and an optimal MT volume per center as 150. Multivariable-adjusted generalized linear models were used to evaluate factors associated with MTA. Results: We received 887 responses from 67 countries. The median global MTA was 2.79% (interquartile range, 0.70–11.74). MTA was <1.0% for 18 (27%) countries and 0 for 7 (10%) countries. There was a 460-fold disparity between the highest and lowest nonzero MTA regions and low-income countries had 88% lower MTA compared with high-income countries. The global MT operator availability was 16.5% of optimal and the MT center availability was 20.8% of optimal. On multivariable regression, country income level (low or lower–middle versus high: odds ratio, 0.08 [95% CI, 0.04–0.12]), MT operator availability (odds ratio, 3.35 [95% CI, 2.07–5.42]), MT center availability (odds ratio, 2.86 [95% CI, 1.84–4.48]), and presence of prehospital acute stroke bypass protocol (odds ratio, 4.00 [95% CI, 1.70–9.42]) were significantly associated with increased odds of MTA. Conclusions: Access to MT on a global level is extremely low, with enormous disparities between countries by income level. The significant determinants of MT access are the country’s per capita gross national income, prehospital LVO triage policy, and MT operator and center availability.

Objective Schwannomas are common nerve sheath tumors and may occur anywhere in the body. 4% of head and neck schwannomas occur in the sinonasal cavity, and fewer yet have an intracranial component, making these presentations extremely rare. Furthermore, schwannomas present with nonspecific imaging signs and can only be definitively differentiated via histopathologic review, leading to misdiagnosis as various nasal tumors. We aim to conduct a review of published literature on sinonasal schwannomas with and without intracranial extension and provide additional case representations. Methods A literature review was conducted using the PubMed Database with the terms “sinonasal schwannoma,” “intracranial,” “anterior skull base,” and “schwannoma.” Results were reviewed, and additional cases identified were referenced and included in the study. Inclusion criteria were any case with intracranial extension of the schwannoma. There were no exclusion criteria. Review data was compiled into Excel and used for data analysis and comparison. Additionally, a search was done within our institution to identify additional cases of sinonasal schwannoma. Results We identified 17 cases of sinonasal schwannoma with intracranial extension, five from our institution and twelve from literature. Analysis revealed: 8 females (47%), 9 males (53%), 9 patients presented with headaches (53%), 6 patients presented with anosmia (35%), 4 patients presented with nasal obstruction (24%), and 2 patients with no symptoms (12%). Mean age and median were 39.4 ± 10.1 and 40, respectively. For treatment, 4 patients underwent endoscopic resection (24%), 11 underwent craniotomy (65%), and data was unavailable for 2 patients. Post-treatment complications occurred in 6 patients, 5 had CSF leaks (29%) and 1 had a hematoma (6%). Conclusion We identified and discussed 17 cases of sinonasal schwannoma with intracranial extension. We hope our review provides insight for clinicians to maintain schwannoma as a potential differential when evaluating nasal and anterior skull base masses.

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.

While abnormalities of the hippocampus have been well characterized in temporal lobe epilepsy, various additional temporal lobe abnormalities have also been described. One poorly understood entity, the so-called temporal pole blurring (TPB), is one of the more frequently described neocortical abnormalities in TLE and is thought to represent dysmyelination and axonal loss due to chronic electrical perturbations in early age-onset temporal lobe epilepsy. In this study, we describe the first reported cases of TPB diagnosed by a recently described MRI sequence known as 3D Edge-Enhancing Gradient Echo (3D-EDGE), which has an effective “myelin weighting” making it exquisitely sensitive to this temporal pole dysmyelination. The value of detection of TPB lies in lateralizing seizure onset, as well as predicting a lower baseline neuropsychological performance compared to temporal lobe epilepsy without TPB. Additionally, it is critical to not mistake TPB for alternative diagnoses, such as focal cortical dysplasia or neoplasm.

OBJECTIVE Recent studies have proposed resection of the T2 FLAIR hyperintensity beyond the T1 contrast enhancement (supramarginal resection [SMR]) for IDH–wild-type glioblastoma (GBM) to further improve patients’ overall survival (OS). GBMs have significant variability in tumor cell density, distribution, and infiltration. Advanced mathematical models based on patient-specific radiographic features have provided new insights into GBM growth kinetics on two important parameters of tumor aggressiveness: proliferation rate (ρ) and diffusion rate (D). The aim of this study was to investigate OS of patients with IDH–wild-type GBM who underwent SMR based on a mathematical model of cell distribution and infiltration profile (tumor invasiveness profile). METHODS Volumetric measurements were obtained from the selected regions of interest from pre- and postoperative MRI studies of included patients. The tumor invasiveness profile (proliferation/diffusion [ρ/D] ratio) was calculated using the following formula: ρ/D ratio = (4π/3) 2/3 × (6.106/[V T2 1/1 − V T1 1/1 ]) 2 , where V T2 and V T1 are the preoperative FLAIR and contrast-enhancing volumes, respectively. Patients were split into subgroups based on their tumor invasiveness profiles. In this analysis, tumors were classified as nodular, moderately diffuse, or highly diffuse. RESULTS A total of 101 patients were included. Tumors were classified as nodular (n = 34), moderately diffuse (n = 34), and highly diffuse (n = 33). On multivariate analysis, increasing SMR had a significant positive correlation with OS for moderately and highly diffuse tumors (HR 0.99, 95% CI 0.98–0.99; p = 0.02; and HR 0.98, 95% CI 0.96–0.99; p = 0.04, respectively). On threshold analysis, OS benefit was seen with SMR from 10% to 29%, 10% to 59%, and 30% to 90%, for nodular, moderately diffuse, and highly diffuse, respectively. CONCLUSIONS The impact of SMR on OS for patients with IDH–wild-type GBM is influenced by the degree of tumor invasiveness. The authors’ results show that increasing SMR is associated with increased OS in patients with moderate and highly diffuse IDH–wild-type GBMs. When grouping SMR into 10% intervals, this benefit was seen for all tumor subgroups, although for nodular tumors, the maximum beneficial SMR percentage was considerably lower than in moderate and highly diffuse tumors.