Carotid Web Phenotype Is Uncommonly Associated With Classic Fibromuscular Dysplasia: A Retrospective Observational Study.

BACKGROUND AND PURPOSE: Carotid web (CaW) is an intimal form of fibromuscular dysplasia (FMD) involving the carotid bulb which has been increasingly recognized as a potential cause of recurrent ischemic strokes. It is overlooked as a separate entity and often dismissed if no coexistent signs of classic FMD changes are observed. We aim to evaluate the frequency of classic FMD in high-yield vascular territories in patients with symptomatic CaW. METHODS: This was a retrospective analysis of a symptomatic CaW database of 2 comprehensive stroke centers (spanning September 2014-October 2020). The diagnosis of a CaW during a stroke workup was defined as the presence of a shelf-like linear filling defect in the posterior aspect of the carotid bulb on computed tomography angiography in patients with acute ischemic stroke or transient ischemic attack of undetermined cause after a thorough evaluation. Neck computed tomography angiography and renal conventional angiography images were independently evaluated by two readers blinded to the laterality and clinical details to inspect the presence of underlying classic FMD. RESULTS: Sixty-six patients with CaW were identified. Median age was 51 years (interquartile range, 42-57), and 74% were women. All patients had neck computed tomography angiography (allowing for bilateral vertebral and carotid evaluation), whereas 47 patients had additional digital subtraction angiography (which evaluated 47 carotids ipsilateral to the stroke and 10 contralateral carotids). Internal carotid artery classic FMD changes were noted in only 6 out of 66 (9%) in the ipsilateral carotids. No contralateral carotid or vertebral artery classic FMD changes were observed. Renal artery catheter-based angiography was obtained in 16 patients/32 arteries and only 1 patient/2 renal arteries demonstrated classic FMD changes. CONCLUSIONS: CaW phenotype is uncommonly associated with classic FMD changes. Coexistent classic FMD does not constitute a useful marker to corroborate or exclude CaW diagnosis.

Collateral status, hyperglycemia, and functional outcome after acute ischemic stroke.

BACKGROUND: Mixed data exist regarding the association between hyperglycemia and functional outcome after acute ischemic stroke when accounting for the impact of leptomeningeal collateral flow. We sought to determine whether collateral status modifies the association between treatment group and functional outcome in a subset of patients with large vessel occlusion enrolled in the Stroke Hyperglycemia Insulin Network Effort (SHINE) trial. METHODS: In this post-hoc analysis, we analyzed patients enrolled into the SHINE trial with anterior circulation large vessel occlusion who underwent imaging with CT angiography prior to glucose control treatment group assignment. The primary analysis assessed the degree to which collateral status modified the effect between treatment group and functional outcome as defined by the 90-day modified Rankin Scale score. Logistic regression was used to model the data, with adjustments made for thrombectomy status, age, post-perfusion thrombolysis in cerebral infarction (TICI) score, tissue plasminogen activator (tPA) use, and baseline National Institutes of Health Stroke Scale (NIHSS) score. Five SHINE trial centers contributed data for this analysis. Statistical significance was defined as a p-value < 0.05. RESULTS: Among the 1151 patients in the SHINE trial, 57 with angiographic data were included in this sub-analysis, of whom 19 had poor collaterals and 38 had good collaterals. While collateral status had no effect (p = 0.855) on the association between glucose control treatment group and functional outcome, patients with good collaterals were more likely to have a favorable functional outcome (p = 0.001, OR 5.02; 95% CI 1.37-16.0). CONCLUSIONS: In a post-hoc analysis using a subset of patients with angiographic data enrolled in the SHINE trial, collateral status did not modify the association between glucose control treatment group and functional outcome. However, consistent with prior studies, there was a significant association between good collateral status and favorable outcome in patients with large vessel occlusion stroke. TRIAL REGISTRATION: ClinicalTrials.gov Identifier is NCT01369069. Registration date is June 8, 2011.

Acute Neurological Deterioration in Large Vessel Occlusions and Mild Symptoms Managed Medically.

Background and Purpose- It is unclear which factors predict acute neurological deterioration in patients with large vessel occlusion and mild symptoms. We aim to evaluate the frequency, timing, and potential predictors of acute neurological deterioration ≥4 National Institutes of Health Stroke Scale (NIHSS) points in medically managed patients with large vessel occlusion and mild presentation. Methods- Single-center retrospective study of patients with consecutive minor stroke (defined as NIHSS score of ≤5 on presentation) and large vessel occlusion from January 2014 to December 2017. Primary outcome was acute neurological deterioration ≥4 NIHSS points during the hospitalization. Secondary outcomes included ΔNIHSS (defined as discharge minus admission NIHSS score). Results- Among 1133 patients with acute minor strokes, 122 (10.6%) had visible occlusions on computed tomography angiography/magnetic resonance angiography. Twenty-four (19.7%) patients had ≥4 points deterioration on NIHSS at a median of 3.6 (1-16) hours from arrival. No clinical or radiological predictors of acute neurological deterioration ≥4 NIHSS points were observed on multivariable analysis. Rescue endovascular thrombectomy was performed more often in the ones with acute neurological deterioration ≥4 NIHSS points compared with patients with no deterioration (54% versus 0%; P<0.001). Acute neurological deterioration ≥4 NIHSS points was associated with ΔNIHSS ≥4 points (33% versus 4.9%; P<0.01) and a trend toward lower independence rates at discharge (50% versus 70%; P=0.06) compared with the group with no deterioration. In patients with any degree of neurological worsening, patients who underwent rescue thrombectomy were more likely to be independent at discharge (73% versus 38%; P=0.02) and to have a favorable ΔNIHSS (-2 [-3 to 0] versus 0 [-1 to 6]; P=0.05) compared with the ones not offered rescue thrombectomy. Conclusions- Acute neurological deterioration ≥4 NIHSS points was observed in a fifth of patients with large vessel occlusion and mild symptoms, occurred very early in the hospital course, impacted functional outcomes, and could not be predicted by any of the studied clinical and radiological variables. Rescue thrombectomy was associated with improved clinical outcomes at discharge in patients with neurological deterioration.

Bailout endovascular techniques applied in a complicated basilar thrombectomy case.

Patients with stroke symptoms due to acute basilar artery occlusion can benefit from endovascular thrombectomy.1 2 Several papers have reported unwanted events during thrombectomy procedures such as breakage, fragmentation, or even intravascular migration of the devices or catheter pieces. These papers also presented methods or techniques to retrieve defective devices such as a snare, retrievable stents, or balloons.3-6 Video 1 presents a case of basilar thrombectomy that was complicated with fragmentation and then distal migration of a Marksman microcatheter tip into the left posterior cerebral artery. The video shows the bailout technique that was used to retrieve the migrated catheter tip using a gentle/simple and posterior circulation-friendly technique-a technique based on fundamental neurointerventional concepts. neurintsurg;16/2/217/V1F1V1Video 1 This video demonstrates the use of a bailout technique to retrieve a migrated microcatehter tip after basilar artery thrombectomy.

Pipeline embolization device as a standalone curative approach for recurrent sigmoid sinus DAVF.

Dural arteriovenous fistulas (dAVFs) can occur as complications after surgical procedures, especially following the resection of meningiomas near the dural sinus. This case report presents a 74-year-old male who developed a recurrent sigmoid dAVF following meningioma resection. Initially treated with transvenous embolization and middle meningeal artery embolization, the dAVF recurred with worsening clinical symptoms. Conventional treatment options, including sinus sacrifice and transarterial embolization, were unsuitable due to the critical role of the patient's dominant right sigmoid sinus in cerebral venous drainage. Consequently, a reconstructive approach was employed using a pipeline embolization device (PED) construct. The PED successfully occluded the dAVF while preserving the function of the sigmoid sinus. A follow-up angiogram confirmed stable occlusion and normalization of intracranial venous drainage. This case underscores the potential of flow diversion as a viable treatment option for dAVFs, particularly in scenarios where preserving venous sinus function is paramount.

Venous Anatomy of the Central Nervous System.

Comprehensive understanding of venous anatomy is a key factor in the approach to a multitude of conditions. Moreover, the venous system has become the center of attention as a new frontier for treatment of diseases such as idiopathic intracranial hypertension (IIH), arteriovenous malformation (AVM), pulsatile tinnitus, hydrocephalus, and cerebrospinal fluid (CSF) venous fistulas. Its knowledge is ever more an essential requirement of the modern brain physician. In this article, the authors explore the descriptive and functional anatomy of the venous system of the CNS in 5 subsections: embryology, dural sinuses, cortical veins, deep veins, and spinal veins.

Comprehensive Analysis of Post-Pipeline Endothelialization and Remodeling.

BACKGROUND AND PURPOSE: Successful post-flow-diverter endoluminal reconstruction is widely believed to require endothelial overgrowth of the aneurysmal inflow zone. However, endothelialization/neointimal overgrowth is a complex process, over which we currently have very limited influence. Less emphasized is vascular remodeling of the target arterial segment, the dynamic response of the vessel to flow-diverter implantation. This process is distinct from flow modifications in covered branches. It appears that basic angiographic methods allow simple and useful observations. The purpose of this article was to quantitatively evaluate observable postimplantation changes in target vessels following deployment of Pipeline endoluminal constructs. MATERIALS AND METHODS: One hundred consecutive adults with unruptured, previously untreated, nondissecting aneurysms treated with the Pipeline Embolization Device with Shield Technology and the availability of follow-up conventional angiography were studied with 2D DSA imaging. Target vessel size; Pipeline Embolization Device diameter; endothelial thickness; and various demographic, antiplatelet, and device-related parameters were recorded and analyzed. RESULTS: The thickness of neointimal overgrowth (mean, 0.3 [SD, 0.1] mm; range, 0.1-0.7 mm) is inversely correlated with age and is independent of vessel size, smoking status, sex, and degree of platelet inhibition. The decrease in lumen diameter caused by neointimal overgrowth, however, appears counteracted by outward remodeling (dilation) of the target arterial segment. This leads to an increase in the diameter with a corresponding decrease in length (foreshortening) of the implanted Pipeline Embolization Device. This physiologic remodeling process affects optimally implanted devices and is not a consequence of stretching, device migration, vasospasm, and so forth. A direct, linear, statistically significant relationship exists between the degree of observed outward remodeling and the diameter of the implanted Pipeline Embolization Device relative to the target vessel. Overall, remodeled arterial diameters were reduced by 15% (SD, 10%) relative to baseline and followed a normal distribution. Clinically relevant stenosis was not observed. CONCLUSIONS: Vessel healing involves both outward remodeling and neointimal overgrowth. Judicial oversizing could be useful in specific settings to counter the reduction in lumen diameter due to postimplant neointimal overgrowth; however, this overszing needs to be balanced against the decrease in metal coverage accompanying the use of oversized devices. Similar analysis for other devices is essential.

Learning Curve of Robotic End-to-Side Microanastomoses.

BACKGROUND AND OBJECTIVES: Robotics are becoming increasingly widespread within various neurosurgical subspecialties, but data pertaining to their feasibility in vascular neurosurgery are limited. We present our novel attempt to evaluate the learning curve of a robotic platform for microvascular anastomoses. METHODS: One hundred and sixty one sutures were performed and assessed. Fourteen anastomoses (10 robotic [MUSA-2 Microsurgical system; Microsure] and 4 hand-sewn) were performed by the senior author on 1.5-mm caliber tubes and recorded with the Kinevo 900 (Zeiss) operative microscope. We separately compared interrupted sutures (from needle insertion until third knot) and running sutures (from needle insertion until loop pull-down). Average suture timing across all groups was compared using an unpaired Student's t test. Exponential smoothing (α = 0.2) was then applied to the robotic data sets for validation and a second set of t tests were performed. RESULTS: We compared 107 robotic sutures with 54 hand-sewn sutures. There was a significant difference between the average time/stitch for the robotic running sutures (n = 55) and the hand-sewn running sutures (n = 31) (31.2 seconds vs 48.3 seconds, respectively; P-value = .00052). Exponential smoothing (α = 0.2) reinforced these results (37.6 seconds vs 48.3 seconds; P-value = .014625). Average robotic running times surpassed hand-sewn by the second anastomosis (38.8 seconds vs 48.3 seconds) and continued to steadily decrease with subsequent stitches. The average of the robotic interrupted sutures (n = 52) was significantly longer than the hand-sewn (n = 23) (171.3 seconds vs 70 seconds; P = .000024). Exponential smoothing (α = 0.2) yielded similar results (196.7 seconds vs 70 seconds; P = .00001). However, average robotic interrupted times significantly decreased from the first to the final anastomosis (286 seconds vs 105.2 seconds; P = .003674). CONCLUSION: Our results indicate the learning curve for robotic microanastomoses is short and encouraging. The use of robotics warrants further study for potential use in cerebrovascular bypass procedures.

Transpalpebral/Blepharoplasty Incision and Supraorbital Craniotomy for the Treatment of Ethmoidal Dural Arteriovenous Fistulas: A Case Series.

BACKGROUND AND OBJECTIVES: Inherent complex angioarchitecture associated with ethmoidal dural arteriovenous fistulas (dAVFs) can make endovascular treatment methods challenging. Many surgical approaches are accompanied by unfavorable cosmetic results such as facial scarring. Blepharoplasty incision of the eyelid offers a minimal, well-hidden scar compared with other incision sites while offering the surgeon optimal visualization of pathogenic structures. This case series aims to report an initial assessment of the safety and efficacy of supraorbital craniotomy by blepharoplasty transpalpebral (eyelid) incision for surgical disconnection of ethmoidal dAVFs. METHODS: Retrospective chart review was conducted for all patients who underwent blepharoplasty incision and craniotomy for disconnection of ethmoidal dAVFs at our institution between October 2011 and February 2023. Patient charts and follow-up imaging were reviewed to report clinical and angiographic outcomes as well as periprocedural and follow-up complications. RESULTS: Complete obliteration and disconnection of ethmoidal dAVF was achieved in all 6 (100%) patients as confirmed by intraoperative angiogram with no resulting morbidity or mortality. Periprocedural complications included one case of transient nasal cerebrospinal fluid leak that was self-limiting and resolved before discharge without intervention. CONCLUSION: Surgical treatment for ethmoidal dAVFs, specifically by transpalpebral incision and supraorbital craniotomy, is a safe and effective treatment option and affords the surgeon greater access to the floor of the anterior fossa when necessary. In addition, blepharoplasty incision addressed patient concerns for facial scarring compared with other incision sites by creating a more well-hidden, minimal scar in the natural folds of the eyelid for patients with an eyelid crease.

Treatment of Acute Iatrogenic Cerebrovascular Injury Using Flow Diverter Stents.

BACKGROUND AND OBJECTIVES: Iatrogenic cerebrovascular injury can cause intracranial hemorrhage and pseudoaneurysm formation, putting patients at high risk for postoperative bleeding. No consensus for management exists. This study describes endovascular treatment of these acute injuries with flow diverter stents. METHODS: Electronic medical records were retrospectively reviewed for injury type and etiology, timing of diagnosis, and endovascular management, including antiplatelet regimens, embolization results, and clinical outcome. RESULTS: Six patients were included. Three suffered an injury to the internal carotid artery, 1 suffered an injury to the left anterior cerebral artery, 1 suffered an injury to the right posterior cerebral artery, and 1 suffered an injury to the basilar artery. Four of the 6 injuries occurred during attempted tumor resection, 1 occurred during cerebrospinal fluid leak repair, and 1 occurred during an ophthalmic artery aneurysm clipping. All injuries resulted in pseudoaneurysm formation. Four were immediately detected on angiography; 2 were initially negative on imaging. Five were treated with a pipeline embolization device, and 1 was treated with a Silk Vista Baby. Two were treated with 2 pipeline embolization devices telescopically overlapped across the pseudoaneurysm. All devices deployed successfully. No pseudoaneurysm recurrence or rebleeding occurred. No parent artery occlusion or stenosis was observed, and complete pseudoaneurysm occlusion was observed in 4 patients (in 2 patients, follow-up imaging could not be obtained). CONCLUSION: With proper antiplatelet regimens, flow diverter stents can be used safely to successfully treat complex acute iatrogenic injuries. Early repeat angiogram is needed when immediate postinjury imaging does not discover the point of vessel injury.

Association Between Hypertensive Disorders of Pregnancy and Interval Neurocognitive Decline: An Analysis of the Hispanic Community Health Study/Study of Latinos.

OBJECTIVE: To evaluate whether hypertensive disorders of pregnancy, including gestational hypertension, preeclampsia, and eclampsia, are associated with cognitive decline later in life among U.S. Hispanic/Latina individuals. METHODS: The HCHS/SOL (Hispanic Community Health Study/Study of Latinos) is a prospective population-based study of Hispanic/Latino individuals aged 18-74 years from four U.S. communities. This analysis included parous individuals aged 45 years or older who participated in the HCHS/SOL clinic study visit 1 (2008-2011) neurocognitive assessment and subsequently completed a repeat neurocognitive assessment as part of the Study of Latinos-Investigation of Neurocognitive Aging ancillary study visit 2 (2015-2018). Hypertensive disorders of pregnancy were assessed retrospectively by self-report of any gestational hypertension, preeclampsia, or eclampsia. Cognitive functioning was measured at both study visits with the Brief Spanish-English Verbal Learning Test, Digit Symbol Substitution, and Word Fluency. A regression-based approach was used to define cognitive decline at visit 2 as a function of cognition at visit 1 after adjustment for age, education, and follow-up time. Linear regression models were used to determine whether hypertensive disorders of pregnancy or their component diagnoses were associated with standardized cognitive decline after adjustment for sociodemographic characteristics, clinical and behavioral risk factors, and follow-up time. RESULTS: Among 3,554 individuals included in analysis, the mean age was 56.2 years, and 467 of individuals (13.4%) reported at least one hypertensive disorder of pregnancy. Individuals with hypertensive disorders of pregnancy compared with those without were more likely to have higher mean systolic blood pressure, fasting glucose, and body mass index. After an average of 7 years of follow-up, in fully adjusted models, gestational hypertension was associated with a 0.17-SD relative decline in Digit Symbol Substitution scores (95% CI, -0.31 to -0.04) but not other cognitive domains (Brief Spanish-English Verbal Learning Test or Word Fluency). Neither preeclampsia nor eclampsia was associated with neurocognitive differences. CONCLUSION: The presence of preeclampsia or eclampsia was not associated with interval neurocognitive decline. In this cohort of U.S. Hispanic/Latina individuals, gestational hypertension alone was associated with decreased processing speed and executive functioning later in life.

Assessing superficial temporal artery-middle cerebral artery anastomosis patency using FLOW 800 hemodynamics.

OBJECTIVE: The objective of this study was to investigate the use of indocyanine green videoangiography with FLOW 800 hemodynamic parameters intraoperatively during superficial temporal artery-middle cerebral artery (STA-MCA) bypass surgery to predict patency prior to anastomosis performance. METHODS: A retrospective and exploratory data analysis was conducted using FLOW 800 software prior to anastomosis to assess four regions of interest (ROIs; proximal and distal recipients and adjacent and remote gyri) for four hemodynamic parameters (speed, delay, rise time, and time to peak). Medical records were used to classify patients into flow and no-flow groups based on immediate or perioperative anastomosis patency. Hemodynamic parameters were compared using univariate and multivariate analyses. Principal component analysis was used to identify high risk of no flow (HRnf) and low risk of no flow (LRnf) groups, correlated with prospective angiographic follow-ups. Machine learning models were fitted to predict patency using FLOW 800 features, and the a posteriori effect of complication risk of those features was computed. RESULTS: A total of 39 cases underwent STA-MCA bypass surgery with complete FLOW 800 data collection. Thirty-five cases demonstrated flow after anastomosis revascularization and were compared with 4 cases with no flow after revascularization. Proximal and distal recipient speeds were significantly different between the no-flow and flow groups (proximal: 238.3 ± 120.8 and 138.5 ± 93.6, respectively [p < 0.001]; distal: 241.0 ± 117.0 and 142.1 ± 103.8, respectively [p < 0.05]). Based on principal component analysis, the HRnf group (n = 10) was characterized by high-flow speed (> 75th percentile) in all ROIs, whereas the LRnf group (n = 10) had contrasting patterns. In prospective long-term follow-up, 6 of 9 cases in the HRnf group, including the original no-flow cases, had no or low flow, whereas 8 of 8 cases in the LRnf group maintained robust flow. Machine learning models predicted patency failure with a mean F1 score of 0.930 and consistently relied on proximal recipient speed as the most important feature. Computation of posterior likelihood showed a 95.29% chance of patients having long-term patency given a lower proximal speed. CONCLUSIONS: These results suggest that a high proximal speed measured in the recipient vessel prior to anastomosis can elevate the risk of perioperative no flow and long-term reduction of flow. With an increased dataset size, continued FLOW 800-based ROI metric analysis could be used to guide intraoperative anastomosis site selection prior to anastomosis and predict patency outcome.

Spinal dural and epidural fistulas: role of cone beam CT in diagnosis and treatment.

Understanding normal spinal arterial and venous anatomy, and spinal vascular disease, is impossible without flow-based methods. Development of practical spinal angiography led to site-specific categorization of spinal vascular conditions, defined by the 'seat of disease' in relation to the cord and its covers. This enabled identification of targets for highly successful surgical and endovascular treatments, and guided interpretation of later cross-sectional imaging.Spinal dural and epidural arteriovenous fistulas represent the most common types of spinal shunts. Although etiology is debated, anatomy provides excellent pathophysiologic correlation. A spectrum of fistulas, from foramen magnum to the sacrum, is now well-characterized.Most recently, use of cone beam CT angiography has yielded new insights into normal and pathologic anatomy, including venous outflow. It provides unrivaled visualization of the fistula and its relationship with spinal cord vessels, and is the first practical method to study normal and pathologic spinal veins in vivo-with multiple implications for both safety and efficacy of treatments. We advocate consistent use of cone beam CT imaging in modern spinal fistula evaluation.The role of open surgery is likely to remain undiminished, with increasing availability and use of hybrid operating rooms for practical intraoperative angiography enhancing safety and efficacy of complex surgery.

SuperDyna: Unlocking the Potential of Post-Treatment Device Evaluation.

BACKGROUND: Current imaging algorithms for post-device evaluation are limited by either poor representation of the device or poor delineation of the treated vessel. Combining the high-resolution images from a traditional three-dimensional digital subtraction angiography (3D-DSA) protocol with the longer cone-beam computed tomography (CBCT) protocol may provide simultaneous visualization of both the device and the vessel content in a single volume, improving the accuracy and detail of the assessment. We aim here to review our use of this technique which we termed "SuperDyna". METHODS: In this retrospective study, patients who underwent an endovascular procedure between February 2022 and January 2023 were identified. We analyzed patients who had both non-contrast CBCT and 3D-DSA post-treatment and collected information on pre-/post-blood urea nitrogen, creatinine, radiation dose, and the intervention type. RESULTS: In 1 year, SuperDyna was performed in 52 (of 1935, 2.6%) patients, of which 72% were women, median age 60 years. The most common reason for the addition of the SuperDyna was for post-flow diversion assessment (n=39). Renal function tests showed no changes. The average total procedure radiation dose was 2.8 Gy, with 4% dose and ~20 mL of contrast attributed to the additional 3D-DSA needed to generate the SuperDyna. CONCLUSIONS: The SuperDyna is a fusion imaging method that combines high-resolution CBCT and contrasted 3D-DSA to evaluate intracranial vasculature post-treatment. It allows for more comprehensive evaluation of the device position and apposition, aiding in treatment planning and patient education.

Superior hypophyseal arteries: angiographic re-discovery, comprehensive assessment, and embryologic implications.

The superior hypophyseal arteries (SHAs) are well known in anatomical and surgical literature, with a well-established role in supply of the anterior hypophysis and superjacent optic apparatus. However, due to small size and overlap with other vessels, in vivo imaging by any modality has been essentially non-existent. Advances in high resolution cone beam CT angiography (CBCTA) now enables this deficiency to be addressed. This paper presents, to the best of our knowledge, the first comprehensive in vivo imaging evaluation of the SHAs. METHODS: Twenty-five CBCTA studies of common or internal carotid arteries were obtained for a variety of clinical reasons. Dedicated secondary reconstructions of the siphon were performed, recording the presence, number, and supply territory of SHAs. A spectrum approach, emphasizing balance with adjacent territories (inferior hypophyseal, ophthalmic, posterior and communicating region arteries) was investigated. RESULTS: The SHAs were present in all cases. Supply of the anterior pituitary was nearly universal (96%) and almost half (44%) originated from the 'cave' region, in excellent agreement with surgical literature. Optic apparatus supply was more difficult to adjudicate, but appeared present in most cases. The relationship with superior hypophyseal aneurysms was consistent. Patency following flow diverter placement was typical, despite a presumably rich collateral network. Embryologic implications with respect to the ophthalmic artery and infraoptic course of the anterior cerebral artery are intriguing. CONCLUSIONS: SHAs are consistently seen with CBCTA, allowing for correlation with existing anatomical and surgical literature, laying the groundwork for future in vivo investigation.

Access to cavernous dAVF via occluded superior petrosal Sinus.

There are multiple treatment alternatives for cavernous dAVFs, with transvenous routes being most common. Among these routes, occluded inferior petrosal sinus is well-described, and, apart from being imaginative and elegant, it is also safe and effective. Herein we describe the application of this method to reach the fistulous pouch of a cavernous dAVF via an occluded superior petrosal sinus.

An unusual anatomical variant: A transclival artery supplying the vertebrobasilar circulation.

The persistent carotid-vertebrobasilar anastomoses are arterial communications between the anterior and posterior circulations due to the persistence of embryological connections. We here present an extremely rare instance of a transclival persistent carotid-vertebrobasilar anastomosis in a 10-month-old infant, which does not fit into any of the traditionally described categories, such as the trigeminal artery, hypoglossal artery, or proatlantal artery.

Cerebral venous anatomy: implications for the neurointerventionalist.

Meaningful contributions to neurointerventional practice may be possible by considering the dynamic aspects of angiography in addition to fixed morphologic information. The functional approach to venous anatomy requires integration of the traditional static anatomic features of the system-deep, superficial, posterior fossa, medullary veins, venous sinuses, and outflow routes into an overall appreciation of how a classic model of drainage is altered, embryologically, or pathologically, depending on patterns of flow-visualization made possible by angiography. In this review, emphasis is placed on balance between alternative venous networks and their redundancy, and the problems which arise when these systems are lacking. The role of veins in major neurovascular diseases, such as dural arteriovenous fistulae, arteriovenous malformations, pulsatile tinnitus, and intracranial hypertension, is highlighted, and deficiencies in knowledge emphasized.

Principles, techniques and applications of high resolution cone beam CT angiography in the neuroangio suite.

The aim of this review is to describe the acquisition and reformatting of state of the art high resolution cone beam CT (HR-CBCT) and demonstrate its role in multiple neurovascular conditions as a tool to improve the understanding of disease and guide therapeutic decisions. First, we will review the basic principle of CBCT acquisition, followed by the injection protocols and the reformatting paradigms. Next, multiple applications in different pathological conditions such as aneurysms, arteriovenous malformations, dural arteriovenous fistulas, and stroke will be described. HR-CBCT angiography, widely available, is uniquely useful in certain clinical scenarios to improve the understanding of disease and guide therapeutic decisions. It rapidly is becoming an essential tool for the contemporary neurointerventionalist.AChoAho.