Diagnosis of Small Unruptured Intracranial Aneurysms : Comparison of 7 T versus 3 T MRI.

PURPOSE: Differentiating normal anatomical variants such as an infundibulum or a vascular loop from true intracranial aneurysms is crucial for patient management. We hypothesize that high-resolution 7 T magnetic resonance imaging (MRI) improves the detection and characterization of normal anatomical variants that may otherwise be misdiagnosed as small unruptured aneurysms. METHODS: This is a retrospective, single-center study. All patients were scanned on a clinically approved 7 T MRI scanner and on a 3 T scanner. Image analysis was performed independently by three neuroradiologists blinded to clinical information. The presence of an unruptured intracranial aneurysm (UIA) and level of diagnostic certainty were assessed and the interrater agreement was calculated. If an aneurysm was present, the anatomic location and shape were recorded and compared. RESULTS: In total, 53 patients with equivocal cerebrovascular findings on 1.5 T or 3 T MRI referred for a 7T MRI examination were included. Aneurysms were suspected in 42 patients examined at 3 T and in 23 patients at 7 T (rate difference 36%, 95% confidence interval, CI, 19-53%, p-value < 0.001). Major disagreement between the field strengths was observed in the A1 segment of anterior cerebral artery/anterior communicating artery (A1/ACOM) complex. The interrater agreement among the readers on the presence of an aneurysm on 7 T MRI was higher than that for 3 T MRI (0.925, 95% CI 0.866-0.983 vs. 0.786, 95% CI 0.700-0.873). CONCLUSION: Our analysis demonstrates a significantly higher interrater agreement and improved diagnostic certainty when small intracranial aneurysms are visualized on 7 T MRI compared to 3 T. In a selected patient cohort, clinical implementation of 7 T MRI may help to establish the definitive diagnosis and thus have a beneficial impact on patient management.

Progressive mechanical and structural changes in anterior cerebral arteries with Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disease and the main cause for dementia. The irreversible neurodegeneration leads to a gradual loss of brain function characterized predominantly by memory loss. Cerebrovascular changes are common neuropathologic findings in aged subjects with dementia. Cerebrovascular integrity is critical for proper metabolism and perfusion of the brain, as cerebrovascular remodeling may render the brain more susceptible to pulse pressure and may be associated with poorer cognitive performance and greater risk of cerebrovascular events. The objective of this study is to provide understanding of cerebrovascular remodeling with AD progression. Anterior cerebral arteries (ACAs) from a total of 19 brain donor participants from controls and pathologically diagnosed AD groups (early-Braak stages I-II; intermediate-Braak stages III-IV; and advanced-Braak stages V-VI) were included in this study. Mechanical testing, histology, advanced optical imaging, and mass spectrometry were performed to study the progressive structural and functional changes of ACAs with AD progression. Biaxial extension-inflation tests showed that ACAs became progressively less compliant, and the longitudinal stress in the intermediate and advanced AD groups was significantly higher than that from the control group. With pathological AD development, the inner and outer diameters of the ACAs remained almost unchanged; however, histology study revealed progressive smooth muscle cell atrophy and loss of elastic fibers which led to compromised structural integrity of the arterial wall. Multiphoton imaging demonstrated elastin degradation at the media-adventitia interface, which led to the formation of an empty band of 21.0 ± 15.4 µm and 32.8 ± 9.24 µm in width for the intermediate and advanced AD groups, respectively. Furthermore, quantitative birefringence microscopy showed disorganized adventitial collagen with AD development. Mass spectrometry analysis provided further evidence of altered collagen content and other extracellular matrix (ECM) molecule and smooth muscle cell changes that were consistent with the mechanical and structural alterations. Collectively, our study provides understanding of the mechanical and structural cerebrovascular deterioration in cerebral arteries with AD, which may be related to neurodegenration and pathology in the brain.

Cerebrovascular Reserve Impairment in the Anterior Cerebral Artery Territory Predicts Deep Temporal Artery Enlargement After Combined Revascularization Surgery in Moyamoya Disease.

OBJECTIVE: A combined surgery of direct and indirect revascularization has been frequently performed in patients with moyamoya disease, though the efficacy of indirect revascularization surgery in adult patients with moyamoya disease has not been established. This study aimed to evaluate superficial temporal artery (STA) and deep temporal artery (DTA) diameters 1 day and 3 months after combined revascularization surgery in patients with moyamoya disease. We also investigated clinical factors related to DTA enlargement after surgery. METHODS: We examined 78 cerebral hemispheres in 57 adult and pediatric patients with moyamoya disease who underwent combined revascularization surgery [STA-MCA bypass and encephalo-duro-myo-synangiosis] in our institution. STA and DTA diameters were measured on axial magnetic resonance angiography images at 1 day and 3 months after surgery. RESULTS: DTA diameter increased in 64 hemispheres (82.1%). DTA diameter increase in association with STA diameter decrease was found in 39 hemispheres (50%). The proportion of hemispheres with a reduction in STA diameter was significantly higher in hemispheres with DTA enlargement than in hemispheres with DTA reduction (P = 0.0088). Among the 64 hemispheres with DTA enlargement, 51 (79.7%) showed cerebrovascular reserve (CVR) impairment in the anterior cerebral artery (ACA) territory before surgery. CVR impairment in the ACA territory was the only clinical factor related to DTA enlargement (P < 0.001). CONCLUSION: The DTA frequently enlarges after combined revascularization surgery, even in adult patients with moyamoya disease. In patients with impaired CVR in the ACA territory, blood supply from the DTA to the ACA territory can be expected after combined revascularization surgery.

Surgical Resection of an Arteriovenous Malformation of the Orbital Surface of the Frontal Lobe with Olfactory Tract Preservation: 2-Dimensional Operative Video.

Medial orbitofrontal area arteriovenous malformations (AVMs) are located in the noneloquent cortex and typically drain superficially into Sylvian veins or the superior sagittal sinus, making them favorable for surgical treatment. However, while typically supplied by pial/cortical branches of the anterior cerebral artery (ACA), they can incorporate the recurrent artery of Heubner and other ACA perforators on their way to the anterior perforated substance located just posterior. We present a case of a 30-year-old female admitted with sudden collapse and intraventricular hemorrhage from a ruptured medial orbitofrontal area AVM. She was admitted to the intensive care unit and an external ventricular drain was placed to treat acute hydrocephalus. Catheter angiography demonstrated an AVM located just anteromedial to the termination of the internal carotid artery with a compact nidus and an associated intranidal flow aneurysm. Arterial supply originated from the orbitofrontal artery off the ACA, with medial lenticulostriates seen coursing past the nidus. Additional supply from the recurrent artery of Heubner could not be excluded. However, a hypodensity in the inferior frontal lobe seen on the presentation computed tomography scan was suggestive of a prior orbitofrontal infarct and thus cortical, rather than perforator, supply. In our practice, treatment of ruptured AVMs is dictated by the patients' clinical recovery and associated high-risk features (e.g., flow aneurysms). In this case, despite the presence of a flow aneurysm, treatment was delayed 18 days due to slow neurologic recovery and family preference. The patient remained in the intensive care unit under close neurologic observation. She was extubated on day 10, and the external ventricular drain was removed on day 12 after confirming resolution of intraventricular hemorrhage. Preoperatively the patient recovered to a Glasgow Coma Scale score of 15. Risks of treatment were discussed, and informed consent was obtained. The patient was treated using a standard pterional craniotomy. We describe the anatomic location of the lesion in the medial orbitofrontal area, the relationship to the olfactory tract and olfactory stria. We demonstrate olfactory tract dissection from its arachnoid cistern between the orbitofrontal lobe and gyrus rectus in order to access the lesion. Indocyanine green angiography is used to help surgical dissection and for quality control at the end of the procedure. We do not perform intraoperative angiography routinely; however, it can be a useful adjunct in deep and/or eloquent locations, which are difficult to image using videoangiography. Nevertheless, in the absence of intraoperative angiography close dissection directly over the nidus on the eloquent side ensures preservation of functional brain. We describe the microsurgical techniques of surgical treatment of AVMs, in particular the "cone" dissection technique of the AVM in order to allow identification of all feeding vessels and tracing "en passant" vessels from proximal to distal, as well as the use of intraoperative videoangiography to elucidate the nidus morphology and immediate postoperative quality control (Video 1, available at https://drive.google.com/file/d/1IXuLg84MwyMek1_Z1f1n7qssLThimvdx/view?usp=sharing).

Double unilateral fenestration of the anterior cerebral artery in the pre-communicating segment: a report of a unique case.

A unique example of two fenestrations of the pre-communicating (A1) segment of the right anterior cerebral artery (ACA) in a 78-year-old woman was a special case among 388 cadaveric specimens. It was found by a retrospective review of the personal data obtained during graduate and undergraduate studies at the Faculty of Medicine. Two unequal fenestrations of the right A1 segment were associated with the presence of a pseudo anterior communicating artery, hypoplasia of the right posterior communicating artery and the left superior cerebellar artery, absence of the right anterior inferior cerebellar artery, and ectasia of the basilar artery; however, the cerebral arteries were without aneurysm(s) or other pathology. The reason could be the almost equal ACA diameter on both sides.

Endovascular Treatment of Fenestration-related Aneurysms : Morphological Features, Operative Techniques and Therapeutic Outcomes.

PURPOSE: Endovascular treatment of fenestration-related aneurysms (FAs) is prone to technical challenges, given the inherent complexities. Herein, we have analyzed FAs in terms of angioarchitectural characteristics and outcomes achieved through endovascular intervention. METHODS: Data accrued prospectively between January 2002 and July 2020 were productive of 105 FAs in 103 patients, each classifiable by the nature of incorporated vasculature as proximal portion, fenestrated limb, or distal end. Our investigation focused on clinical and morphological outcomes, with emphasis on technical aspects of treatment. RESULTS: The FAs selected for study originated primarily in anterior communicating artery (AcomA: 88/105, 83.8%), followed by basilar (7/105, 6.7%), anterior cerebral (4/105, 3.8%), and internal carotid (3/105, 2.8%) arteries. In nearly all locations, proximally situated aneurysms (43/105, 41%) were more frequent than aneurysms arising at distal ends (3/105, 2.8%), but the majority of AcomA lesions involved fenestrated segments (58/88, 65.9%); and most fenestrated channels (90/105, 85.7%) were asymmetric in size. Orifices of smaller fenestrated limbs were intentionally compromised during coil embolization in 23 aneurysms (21.9%), achieving complete (n = 19) or incomplete (n = 4) compromise, without resultant symptomatic ischemia. Saccular occlusion proved satisfactory in 77 lesions (73.3%). In follow-up monitoring of 100 patients for a mean period of 35.3 ± 26.5 months, 17 instances of recanalization (17.0%) occurred (minor, 9; major, 8). There was no recanalization of aneurysms with compromised limbs. CONCLUSION: Coil embolization of FAs is safe and effective, enabling tailored procedures that accommodate aberrant angioanatomic configurations. Compromise of a single limb during coiling also appears safe, conferring long-term protection from recanalization.

Risk factors for intracranial aneurysm rupture in pediatric patients.

BACKGROUND: Intracranial aneurysm (IA) rupture in pediatric patients is a rare but fatal condition. Although risk factors for aneurysm rupture in adults have been well documented, they remain unknown in pediatric patients. METHODS: Data for 94 pediatric patients with IAs were retrospectively analyzed. The patients were divided into ruptured and unruptured groups. Risk factors for aneurysm rupture were analyzed through univariable and multiple logistic regression analyses. Typical patients with risk factors were described. RESULTS: Univariable analyses showed that the unruptured group had significantly higher percentages of giant aneurysms (43.2% vs 12.3%, P = 0.002), wide-neck aneurysms (67.6% vs 29.8%, P = 0.001), and aneurysms located in the internal carotid artery (40.5% vs 3.5%, P < 0.001), while the ruptured group had significantly higher percentages of patients younger than 5 years old (28.1% vs 5.4%, P = 0.013) and aneurysms located in the anterior cerebral artery (24.6% vs 5.4%, P = 0.032), posterior cerebral artery (14.0% vs 0%, P = 0.045), and distal arterial region (DAR) (46.8% vs 27.0%, P < 0.001). Multiple logistic regression analysis confirmed that age 0-5 years (OR = 6.844, P = 0.042) and IAs located in the DAR (OR = 4.162, P = 0.029) were independently related to an increased risk of rupture. Wide-necked aneurysms (OR = 0.235, P = 0.047) were independently associated with a lower risk of rupture. CONCLUSIONS: Among pediatric patients, age younger than 5 years and lesions located in the DAR are independent risk factors for IA rupture, while an IA with a wide neck acts as a protective factor.

Safety Evaluation and Flow Modification in the Anterior Cerebral Artery after Pipeline Embolization Device Deployment across the Internal Carotid Artery Terminus.

METHOD: The clinical and imaging data of PEDs in the postmarket multicenter registry study (PLUS) in China were retrospectively analyzed, and patients were divided into two groups on the basis of the follow-up angiographic results: group 1 (no significant change in A1 blood flow) and group 2 (A1 occlusion or decreased blood flow). We collected patients' baseline data and evaluated the following imaging indicators: diameter and ratio of bilateral A1, M1, and internal carotid artery (ICA) vessels before stenting and the ratio of the PED size (sPED) to the ipsilateral ICA (I-ICA) diameter on the implantation side. RESULTS: A total of 1171 patients were included, of whom 48 met the inclusion criteria (17 in group 1 and 31 in group 2). In group 2, three patients experienced neurological deterioration at follow-up. From the univariate analysis of outcomes, single PED without coils, incomplete aneurysm occlusion (IAO), maximum aneurysm diameter, aneurysms involving the ICA bifurcation (ICAb), and large sPED/I-ICA diameter ratio were included in the multivariate analysis (P < 0.20). The multivariate regression analysis results showed that the ratio of sPED/I-ICA diameter was the factor influencing A1 vessel occlusion. The area under the ROC curve was 73.2%. When the sPED/I-ICA diameter ratio was 1.14, sensitivity was 70.6%, and specificity was 77.4%. CONCLUSION: When an oversized PED is placed from M1 to the ICA, the higher porosity formed at the covered A1 orifice is conducive to maintaining stable A1 blood flow and reducing the risk of A1 vessel occlusion. This trial is registered with ClinicalTrials.gov identifier: NCT03831672.

Bilateral anterior cerebral artery occlusion following CD19- and BCMA-targeted chimeric antigen receptor T-cell therapy for a myeloma patient.

Chimeric antigen receptor T (CAR-T)-cell therapy is a promising treatment for relapsed/refractory multiple myeloma (RRMM). In our previous report, CD19- and BCMA-targeted CAR-T co-administration was associated with a high response rate. Although cytokine release syndrome (CRS) and neurotoxicity are frequent complications following CAR-T treatment, cerebral infarction is rarely reported as a CAR-T-related complication. We reported a 73-year-old female MM patient who received CD19- and BCMA-targeted CAR-T for refractory disease. Her disease responded to CAR-T therapy, but she developed neurological symptoms following CRS. Cranial CT and MRI demonstrated multiple cerebral infarctions and bilateral anterior cerebral artery (ACA) occlusion. We suggest that cerebral infarction other than CAR-T-related neurotoxicity is the underlying cause of abnormal neuropsychological symptoms, and diagnostic imaging tests should be actively performed to exclude ischemic cerebrovascular events.

Anterior Cerebral Artery Stroke: Role of Collateral Systems on Infarct Topography.

Background and Purpose: The circle of Willis (CoW) and leptomeningeal anastomoses play an important role in transforming infarct topography following middle cerebral artery occlusion. Their role in infarct topography following anterior cerebral artery occlusion is not well understood. The aim of this study was to evaluate the role of the CoW and leptomeningeal anastomoses in modifying regional variation in infarct topography following occlusion of the anterior cerebral artery and its branches. Methods: Perfusion and magnetic resonance imaging of patients with anterior cerebral artery stroke and evidence of vessel occlusion were segmented and manually registered to standard brain template for voxel-wise comparison. Next, a computer model of the cerebral arteries was formulated as network of nodes connected by cylindrical pipes. The experiments included occlusion of successive branches of the anterior cerebral artery while the configurations of the CoW were varied. Results: Forty-seven patients with a median age of 77.5 years (interquartile range, 68.0­84.5 years) were studied. The regions with the highest probabilities of infarction were the superior frontal gyrus (probability =0.26) and anterior cingulate gyrus (probability =0.24). The regions around the posterior cingulate gyrus (probability =0.08), paracentral lobule (probability =0.05), precuneus and superior parietal lobule (probability =0.03) had a low probability of infarction. Following occlusions distal to the anterior communicating artery, the computer model demonstrated an increase in flow (>30%) in neighboring cortical arteries with leptomeningeal anastomoses. Conclusions: Traditionally the CoW has been regarded as the primary collateral system. However, our computer model shows that the CoW is only helpful in redirecting flow following proximal vessel occlusions (pre-anterior communicating artery). More important are leptomeningeal anastomoses, which play an essential role in distal vessel occlusions, influencing motor outcome by modifying the posterolateral extent of infarct topography.

Incidence of Neo-Intimal Hyperplasia in Anterior Circulation Aneurysms Following Pipeline Flow Diversion.

INTRODUCTION: Flow diversion of the distal anterior circulation cerebral vasculature may be used for management of wide necked aneurysms not amenable to other endovascular approaches. Follow-up angiography sometimes demonstrates neo-intimal hyperplasia within or adjacent to the stent, however there is limited evidence in the literature examining the incidence in MCA and ACA aneurysms. We present our experience with flow diversion of the distal vasculature and evaluate the incidence of neo-intimal hyperplasia. MATERIALS AND METHODS: Retrospective review of patients who underwent Pipeline embolization device (PED) treatment for ruptured and unruptured anterior circulation aneurysms. RESULTS: A total of 251 anterior circulation aneurysms were treated by pipeline flow diversion, of which 175 were ICA aneurysms, 14 were ACA aneurysms and 18 were MCA aneurysms. 6-month follow-up angiography was available in 207 patients. The incidence of neo-intimal hyperplasia was 15.9%, 21.4%, and 61.1% in ICA, ACA, and MCA aneurysms, respectively. MCA-territory aneurysms developed neo-intimal hyperplasia at a significantly higher rate than aneurysms in other vessel territories. Rates of aneurysmal occlusion did not significantly differ from those patients who did not exhibit intimal hyperplasia on follow-up angiography. CONCLUSION: In our experience, flow diversion of distal wide-necked MCA and ACA aneurysms is a safe and effective treatment strategy. The presence of neo-intimal hyperplasia at 6-month angiography is typically clinically asymptomatic. Given the statistically higher rate of neo-intimal hyperplasia in MCA aneurysms at 6-month angiography, we propose delaying initial follow-up angiography to 12-months and maintaining dual antiplatelet therapy during that time.

Seven Microaneurysms: Description of an Experimental Rodent Model for Neurovascular Training.

AIM: To demonstrate the microsurgical procedures, and to evaluate the feasibility of living models of experimental neurovascular training by developing new complex vascular exercises mimicking the most common intracranial aneurysms. MATERIAL AND METHODS: The procedures were performed under a Zeiss (OPMI pico f170) microscope using basic microsurgery instruments, 10/0 Nylon and blue Polypropylene micro-sutures. We selected adult albino Wistar rats weighing between 258 and 471g each. Seven different aneurysm types were created using carotid, jugular, cava, aorta and femoral vessels. RESULTS: Seven types of aneurysm were designed and created in the rat with a high-medium successful rate. There are differences in terms of realism and the difficulty of performance, according to the different types: lateral wall, bifurcation, top of the basilar, fusiform, fusiform + involved branch, Anterior Communicating Artery (ACoA) and giant. The steps and technical issues to produce these exercises are described. CONCLUSION: We show the feasibility of creating several types of aneurysm using different vessels in a rodent model. Training on these models help to improve microsurgical skills, allowing safe practice for neurosurgeons in all stages of their career.

Tobacco use and age are associated with different morphologic features of anterior communicating artery aneurysms.

We present a cohort of patients with anterior communicating artery (ACoA) aneurysms to investigate morphological characteristics and clinical factors associated with rupture of the aneurysms. 505 patients with ACoA aneurysms were identified at the Brigham and Women's Hospital and Massachusetts General Hospital between 1990 and 2016, with available CT angiography (CTA). Three-dimensional (3D) reconstructions were performed to evaluate aneurysmal morphologic features, including location, projection, irregularity, the presence of daughter dome, height, height/width ratio, and relationships between surrounding vessels. Patient risk factors assessed included patient age, sex, tobacco use, alcohol use, and family history of aneurysms and aneurysmal subarachnoid hemorrhage. Logistic regression was used to build a predictive ACoA score for rupture. Morphologic features associated with ruptured ACoA aneurysms were the presence of a daughter dome (OR 21.4, 95% CI 10.6-43.1), smaller neck diameter (OR 0.55, 95% CI 0.42-0.71), larger aspect ratio (OR 3.57, 95% CI 2.05-6.24), larger flow angle (OR 1.03, 95% CI 1.02-1.05), and smaller ipsilateral A2-ACoA angle (OR 0.98, 95% CI 0.97-1.00). Tobacco use was predominantly associated with morphological factors intrinsic to the aneurysm that were associated with rupture while younger age was also associated with morphologic features extrinsic to the aneurysm that were associated with rupture. The ACoA score had good predictive capacity for rupture with AUC = 0.92 using the 0.632 bootstrap cross-validation for correction of overfitting bias. Ruptured ACoA aneurysms were associated with morphological features that are simple to assess using a simple scoring system. Tobacco use and younger age were predominantly associated with intrinsic and extrinsic morphological features characteristic of rupture, respectively.

Persistent Primitive Olfactory Artery: Three Cases.

ABSTRACT: The persistent primitive olfactory artery is a very rare arterial variant with a little over a score of cases reported in literature so far. We present 3 cases illustrating this entity, which were incidentally diagnosed while imaging for other indications.

Vascular Geometry Associated with Anterior Communicating Artery Aneurysm Formation.

OBJECTIVE: To identify clinical and morphologic risk factors correlated with anterior communicating artery (ACoA) aneurysm formation. METHODS: Three-dimensional morphologic parameters obtained from computed tomography angiography or digital subtraction angiography from 504 patients with ACoA aneurysms and 201 patients with aneurysms in other locations that were diagnosed at Brigham and Women's Hospital and Massachusetts General Hospital between 1990 and 2016 were evaluated. The presence of hypoplastic and aplastic A1 segments and diameters and angles of surrounding parent and daughter vessels were examined. Univariable and multivariable statistical analyses were performed to determine statistical significance. Sensitivity analyses for small (≤3 mm) aneurysms only were also performed. RESULTS: Aplastic and hypoplastic A1 segments were more common in the ACoA group (38.9% vs. 6.5% hypoplastic and 22.2% vs. 0.5% aplastic). In multivariable analysis, the presence of a hypoplastic A1 segment was associated with ACoA aneurysms. An A2-ACoA (daughter-daughter) angle was also significantly associated with ACoA aneurysms in multivariable analysis; however, as Pearson's correlation test between aneurysm width and daughter-daughter angle was significant, the daughter-daughter angle was most likely not independently associated with aneurysm presence, but rather might have been a result of the presence of an aneurysm. Subgroup analyses of small aneurysms (≤3 mm) and of unruptured aneurysms showed similar results. CONCLUSIONS: Our results demonstrate that of all the morphologic parameters, the presence of a hypoplastic A1 segment was the only parameter independently associated with the presence of ACoA aneurysms that was not correlated with aneurysm size and could aid as a simple screening parameter.

Distal anterior cerebral artery aneurysm with bilateral fetal posterior cerebral arteries and trifurcation of anterior cerebral artery.

Developmental vascular anomalies of brain are non-modifiable risk factors for the development of aneurysms and are prone for rupture. We report one such association in a 44-year-old gentleman who succumbed to subarachnoid hemorrhage (SAH) secondary to ruptured distal anterior cerebral artery aneurysm associated with vascular anomalies in the anterior and posterior circulation that included trifurcation of anterior cerebral artery and bilateral fetal posterior cerebral arteries. We identified multiple anomalies in circle of Willis that could have contributed to the formation of aneurysm and early rupture. Knowledge of these variations is essential to plan early and optimum management with close follow-up.

Heritability of territory of ruptured and unruptured intracranial aneurysms in families.

BACKGROUND: A previous study suggested that intracranial aneurysms are more likely to occur in the same arterial territory within families. We aimed to replicate this analysis in independent families and in a sample limited to intracranial aneurysms that ruptured. METHODS: Among families with ≥2 first-degree relatives with intracranial aneurysms, we randomly matched index families to comparison families, and compared concordance in intracranial aneurysm territory between index and comparison families using a conditional logistic events/trials model. We analyzed three European cohorts separately, and pooled the results with those of the Familial Intracranial Aneurysm study by performing an inverse variance fixed effects meta-analysis. The main analysis included both unruptured and ruptured intracranial aneurysms, and a secondary analysis only ruptured intracranial aneurysms. RESULTS: Among 70 Dutch, 142 Finnish, and 34 French families, concordance regarding intracranial aneurysm territory was higher within families than between families, although not statistically significant. Meta-analysis revealed higher concordance in territory within families overall (odds ratio [OR] 1.7, 95%CI 1.3-2.2) and for each separate territory except the anterior cerebral artery. In the analysis of ruptured intracranial aneurysms, overall territory concordance was higher within families than between families (OR 1.8; 95%CI 1.1-2.7) but the territory-specific analysis showed statistical significance only for the internal carotid artery territory. CONCLUSIONS: We confirmed that familial intracranial aneurysms are more likely to occur in the same arterial territory within families. Moreover, we found that ruptured aneurysms were also more likely to occur in the same arterial territory within families.

Artery of Percheron Stroke as an Unusual Cause of Hypersomnia: A Case Series and a Short Literature Review.

The thalamus and the mesencephalon have a complex blood supply. The artery of Percheron (AOP) is a rare anatomical variant. Occlusion of this artery may lead to bithalamic stroke with or without midbrain involvement. Given its broad spectrum of clinical features, AOP stroke is often misdiagnosed. Usually, it manifests with the triad of vertical gaze palsy, memory impairment, and coma. In this article, we report three cases of bilateral thalamic strokes whose clinical presentations were dominated by a sudden onset of hypersomnia. We also reviewed last 5 years' publications related to the AOP strokes in males presenting sleepiness or equivalent terms as a delayed complication. The AOP stroke may present a diagnostic challenge for clinicians which should be considered in the differential diagnosis of hypersomnia.