Journal of neuroimaging : official journal of the American Society of Neuroimaging
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Multicenter Study Clinical Trial
Noninvasive fractional flow on MRA predicts stroke risk of intracranial stenosis.
Fractional flow may identify hemodynamic effects and ischemic risk beyond percent stenosis of an artery. We hypothesized that diminished TOF-MRA signal intensity distal to an intracranial stenosis predicts stroke risk. ⋯ This trial was not registered because enrollment began prior to July 1, 2005.
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Randomized Controlled Trial Multicenter Study
Derivation and evaluation of thresholds for core and tissue at risk of infarction using CT perfusion.
Computed tomography perfusion provides information on tissue viability according to proposed thresholds. We evaluated thresholds for ischemic core and tissue at risk and subsequently tested their accuracy in independent datasets. ⋯ Time-based perfusion thresholds perform well as predictors of tissue at risk of infarction with DT the best predictor. Relative CBF was the best predictor of ischemic core. Evaluation in larger populations is needed to confirm the performance of tissue viability thresholds.
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Multicenter Study
Prevalence of symptomatic intracranial atherosclerosis in Caucasians: a prospective, multicenter, transcranial Doppler study.
There are limited data available regarding symptomatic intracranial atherosclerosis (SIA) prevalence in Caucasians. We sought to investigate SIA prevalence among Caucasian patients hospitalized with acute cerebral ischemia (ACI) in a prospective, multicenter Transcranial Doppler sonography (TCD) study. ⋯ SIA was identified in almost 10% of patients admitted with symptoms of ACI. These preliminary findings support further collaborative initiatives among stroke physicians to increase the yield of SIA detection in Caucasian patients with ACI.
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To assess the safety and efficacy of vertebral artery origin angioplasty and stenting for stroke prevention in a multicenter clinical experience. ⋯ Endovascular intervention of VAOS is associated with low peri-procedural complication rates. Restenosis remains a concern; age and smoking predicted future restenosis.
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Multicenter Study
Preliminary MRI quality assessment and device acceptance guidelines for a multicenter bioclinical study: the GO Glioblastoma Project.
It is a major challenge to guarantee homogeneous acquisition during a prospective multicenter magnetic resonance imaging (MRI) study that makes use of different devices. The goal of the multicenter Grand Ouest Glioblastoma Project (GOGP) was to correlate MRI quantitative parameters with biological markers extracted from image-guided biopsies. Therefore, it was essential to ensure spatial coherence of the parameters as well as the signal intensity and homogeneity. ⋯ A fourth test-object was used to assess T1 accuracy. Although geometry-related parameters, signal-to-noise ratio, uniformity, and T1 measurements varied slightly depending on the different devices, they nevertheless remained within the recommendations and expectations of the multicenter project. This kind of quality control procedure should be undertaken as a prerequisite to any multicenter clinical project involving quantitative MRI and comparison of data acquisitions with quantitative biological image-guided biopsies.