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Updated: May 26, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
3-T high-b-value diffusion-weighted MR imaging of hyperacute ischemic stroke in the vertebrobasilar territory
1Division of Neuroradiology, Department of Neurosurgery, University of Freiburg Medical Center, Breisacher Str. 64, D-79106 Freiburg, Germany. michael_lettau@gmx.de
Background And Purpose:
Diffusion-weighted imaging (DWI) is the key method for diagnosing acute ischemic stroke. Applied b values in stroke diffusion studies are usually in the range of 800-1500 s/mm², but progress in magnetic resonance (MR) technology now permits higher b values. However, it is uncertain whether high-b-value DW sequences improve the detection of acute and hyperacute ischemic lesions. The aim of this study is to explore the sensitivity of high b values vs standard b values at 3T in hyperacute stroke in the vertebrobasilar territory.
Material And Methods:
3-T DWI was performed in referred patients with a clinical diagnosis of hyperacute (<6h from onset) cerebral infarction using conventional MR sequences as well as DW sequences. Examinations included the usual DW sequence (b=1000 s/mm²) and two high-b-value DW sequences (b=3000 s/mm² and b=5000 s/mm²). Patients with hyperacute stroke in the posterior circulation were included if MR imaging, including the usual DW sequence, was normal or if the diagnosis was uncertain.
Results:
In all six studied patients, ischemic lesions were better visualized with high-b-value DWI compared with the usual DWI. On increasing the b value, DW images appeared to be noisier while white-matter tracts became progressively hyperintense.
Conclusion:
At 3T, high-b-value DW sequences may be helpful for diagnosing hyperacute infarctions in the vertebrobasilar territory, but further studies are needed to confirm this hypothesis.
