Publications by authors named "Robert Willinsky"

Introduction: Posterior cerebral artery (PCA) aneurysms represent up to 1% of all cerebral aneurysms. P1-P2 perforator aneurysms are thought to be even less prevalent and often require complex treatment strategies due to their anatomical and morphological characteristics, with risk of a perforator infarct. We studied the treatment of P1-P2 perforator aneurysms in a single-center cohort from a high-volume tertiary center, reporting clinical and anatomical characteristics, treatment strategies, and outcomes.

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Objective: Previous studies using advanced magnetic resonance imaging (MRI) techniques have documented abnormal transmantle bands connecting ectopic nodules to overlying cortex in patients with periventricular nodular heterotopia (PNH). We describe a similar finding using conventional MRI techniques.

Methods: Patients were identified by means of a full-text search of radiological reports.

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Purpose: Traditionally, in the work-up of patients for spontaneous intracranial hypotension, T1 post-contrast imaging is performed in order to assess for pachymeningeal enhancement. The aim of this study is to assess whether pachymeningeal hyperintensity can be identified on a non-contrast FLAIR sequence in these patients as a surrogate sign for pachymeningeal enhancement.

Methods: The patient cohort was identified from a prospectively maintained database of patients with a clinical diagnosis of intracranial hypotension.

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Intradural spinal varices are rare lesions, with only three cases being previously reported in the literature. Previously described patients underwent MRI for non-specific low back pain and radiculopathy and were found to have an intradural lesion adjacent to the cauda equina, mimicking a nerve sheath tumour or ependymoma. Consideration of an intradural varix in the differential diagnosis of an intradural extramedullary spinal lesion is necessary to guide appropriate management.

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Background And Purpose: The goal of reperfusion therapy in acute ischemic stroke is to limit brain infarction. The objective of this study was to investigate whether the beneficial effect of endovascular treatment on functional outcome could be explained by a reduction in post-treatment infarct volume.

Methods: The Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times (ESCAPE) trial was a multicenter randomized open-label trial with blinded outcome evaluation.

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Background: Cerebral cavernous malformations (CCMs) can cause symptomatic intracranial haemorrhage (ICH), but the estimated risks are imprecise and predictors remain uncertain. We aimed to obtain precise estimates and predictors of the risk of ICH during untreated follow-up in an individual patient data meta-analysis.

Methods: We invited investigators of published cohorts of people aged at least 16 years, identified by a systematic review of Ovid MEDLINE and Embase from inception to April 30, 2015, to provide individual patient data on clinical course from CCM diagnosis until first CCM treatment or last available follow-up.

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Background And Purpose: Basilar trunk aneurysms (BTAs), defined as aneurysms distal to the basilar origin and proximal to the origin of the superior cerebellar artery, are rare and challenging to manage. We describe the natural history and management in a consecutive series of BTAs.

Methods: Between 2000 and 2013, 2522 patients with 3238 aneurysms were referred to our institution for aneurysm management.

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Background: Among patients with a proximal vessel occlusion in the anterior circulation, 60 to 80% of patients die within 90 days after stroke onset or do not regain functional independence despite alteplase treatment. We evaluated rapid endovascular treatment in addition to standard care in patients with acute ischemic stroke with a small infarct core, a proximal intracranial arterial occlusion, and moderate-to-good collateral circulation.

Methods: We randomly assigned participants to receive standard care (control group) or standard care plus endovascular treatment with the use of available thrombectomy devices (intervention group).

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ESCAPE is a prospective, multicenter, randomized clinical trial that will enroll subjects with the following main inclusion criteria: less than 12 h from symptom onset, age > 18, baseline NIHSS >5, ASPECTS score of >5 and CTA evidence of carotid T/L or M1 segment MCA occlusion, and at least moderate collaterals by CTA. The trial will determine if endovascular treatment will result in higher rates of favorable outcome compared with standard medical therapy alone. Patient populations that are eligible include those receiving IV tPA, tPA ineligible and unwitnessed onset or wake up strokes with 12 h of last seen normal.

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Introduction: The purpose of our study was to compare the clinical characteristics and preferential localization of aneurysms in three patient groups: single aneurysm, non-mirror multiple aneurysms, and mirror aneurysms.

Methods: We retrospectively reviewed the clinical and radiological data of 2223 consecutive patients harboring 3068 aneurysms registered at the Toronto Western Hospital between May 1994 and November 2010. The patients were divided into single, non-mirror multiple, or mirror aneurysm groups.

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Background And Purpose: Management of unruptured fusiform intracranial aneurysms is controversial because of the paucity of natural history data. We studied their natural history and outcome after treatment.

Methods: We reviewed our neurovascular database from January 2000 to October 2013.

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Objectives: To report the epidemiological features, clinical presentation, angiographic characteristics and therapeutic options, success and complication rates in patients with dural carotid cavernous fistulas (dural CCFs).

Methods: Retrospective evaluation of patients followed in our institution between January of 2005 and September of 2013.

Results: There were 38 patients, 76 % females, with an average age of 63 years.

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Introduction: Perianeurysmal edema and aneurysm wall enhancement are previously described phenomenon after coil embolization attributed to inflammatory reaction. We aimed to demonstrate the prevalence and natural course of these phenomena in unruptured aneurysms after endovascular treatment and to identify factors that contributed to their development.

Methods: We performed a retrospective analysis of consecutively treated unruptured aneurysms between January 2000 and December 2011.

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We describe a 52-year-old woman who presented with meningitis secondary to a pseudomeningocele within the sphenoid sinus derived from a bony defect in the clivus. The bony defect was radiologically characteristic of an ecchordosis physaliphora (EP). She underwent surgical repair of the defect and had resolution of her symptoms.

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Introduction: Despite improvements of embolization agents and techniques, endovascular treatment of spinal dural arteriovenous fistula (SDAVF) is still limited by inconsistent success. The aim of embolization is to occlude initial portion of the draining vein by liquid embolic materials. This study investigates factors that contribute to the success of embolization treatments among SDAVF patients.

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Background And Purpose: Prospective differentiation between reversible cerebral vasoconstriction syndrome and central nervous system vasculitis can be challenging. We hypothesized that high-resolution vessel wall MRI would demonstrate arterial wall enhancement in central nervous system vasculitis but not in reversible cerebral vasoconstriction syndrome.

Methods: We identified all patients with multifocal segmental narrowing of large intracranial arteries who had high-resolution vessel wall MRI and follow-up angiography at our institute over a 4-year period and performed a detailed chart review.

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Background: Brainstem arteriovenous malformations are challenging lesions, and benefits of treatment are uncertain.

Objective: To study the clinical course of Brainstem arteriovenous malformations and the influence of treatments on outcome.

Methods: We reviewed a prospective series of 31 brainstem arteriovenous malformations.

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Purpose: To evaluate the effectiveness and safety of transarterial glue embolization of intracranial dural arteriovenous shunts (DAVS).

Materials And Methods: Institutional review board approval was obtained, with waiver of informed consent, for this retrospective study. From a single-center database of information on 371 intracranial DAVS, data in 115 consecutive patients treated with transarterial glue embolization were identified and assessed.

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Object: The goal was to investigate whether morphological features of aneurysms can be identified that determine initial success and recurrence rates of coiled aneurysms of the basilar artery tip, the posterior communicating artery (PCoA), and the anterior communicating artery.

Methods: The authors evaluated 202 aneurysms in connection with their pretreatment morphological features including size, neck-to-dome ratio, angulation of the aneurysm in relation to the parent artery, orientation of the aneurysm dome, and associated anatomical variations. The mean follow-up was 19 months (range 6-96 months) after endovascular coil occlusion.

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Background: Multidetector computerized tomography angiography (MDCTA) is now a widely accepted technique for the management of intracranial aneurysms.

Objective: To evaluate its accuracy for the postoperative assessment of clipped intracranial aneurysms.

Methods: We analyzed a consecutive series of 31 patients that underwent direct surgical clipping procedures of 38 aneurysms.

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Background And Purpose: Dural arteriovenous shunt (DAVS) is a disease in which abnormal arteriovenous communications develop within the dura. Some case series have suggested DAVS may evolve over time, but the natural history is poorly understood. In this study, we aimed to define the incidence and clinical characteristics of patients with DAVS showing spontaneous angiographic pattern conversion.

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