Paul F Clemmons

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PURPOSE To evaluate the correlation between angiographic measures of Moyamoya disease and tissue-level impairment from measurements of tissue perfusion and cerebrovascular reactivity (CVR). MATERIALS AND METHODS The relationship between perfusion-weighted arterial spin labeling (ASL) and hypercarbic blood oxygenation-level dependent (BOLD) CVR and(More)
BACKGROUND AND PURPOSE A promising method for identifying hemodynamic impairment that may serve as a biomarker for stroke risk in patients with intracranial stenosis is cerebrovascular reactivity (CVR) mapping using noninvasive MRI. Here, abilities to measure CVR safely in the clinic using hypercarbic hyperoxic (carbogen) gas challenges, which increase(More)
PURPOSE Blood oxygenation level-dependent (BOLD)-weighted and vessel-encoded arterial spin labeling (VE-ASL) MRI provide complementary information and can be used in sequence to gauge hemodynamic contributions to cerebrovascular reactivity. Here, cerebrovascular reactivity is assessed using dual echo VE-ASL MRI to understand how VE labeling preparations(More)
BACKGROUND AND PURPOSE Cerebrovascular collaterals have been increasingly recognized as predictive of clinical outcomes in Moyamoya disease in Asia. The aim of this study was to characterize collaterals in North American adult patients with Moyamoya disease and to assess whether similar correlations are valid. MATERIALS AND METHODS Patients with Moyamoya(More)
BACKGROUND AND PURPOSE Technological advances have helped to improve the efficiency of treating patients with large vessel occlusion in acute ischemic stroke. Unfortunately, the sequence of events prior to reperfusion may lead to significant treatment delays. This study sought to determine if high-volume (HV) centers were efficient at delivery of(More)
PURPOSE Advanced neuroimaging techniques may improve patient selection for endovascular stroke treatment but may also delay time to reperfusion. We studied the effect of advanced modality imaging with CT perfusion (CTP) or MRI compared with non-contrast CT (NCT) in a multicenter cohort. MATERIALS AND METHODS This is a retrospective study of 10 stroke(More)
'Vascular steal' has been proposed as a compensatory mechanism in hemodynamically compromised ischemic parenchyma. Here, independent measures of cerebral blood flow (CBF) and blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) responses to a vascular stimulus in patients with ischemic cerebrovascular disease are recorded. Symptomatic(More)
BACKGROUND There are multiple clinical and radiographic factors that influence outcomes after endovascular reperfusion therapy (ERT) in acute ischemic stroke (AIS). We sought to derive and validate an outcome prediction score for AIS patients undergoing ERT based on readily available pretreatment and posttreatment factors. METHODS The derivation cohort(More)
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