Does b1000-b0 Mismatch Challenge Diffusion-Weighted Imaging-Fluid Attenuated Inversion Recovery Mismatch in Stroke?

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• Determining the time since stroke onset is crucial for treatment decisions.
• Current methods for assessing stroke age using imaging have limitations.

Purpose of the Study:

• To evaluate if the lesion visibility mismatch between b1000 and b0 MRI images can serve as a surrogate marker for stroke age.
• To compare this novel approach with the established diffusion-weighted imaging-fluid-attenuated inversion recovery (DWI-FLAIR) mismatch technique.

Main Methods:

• Analysis of 112 patients from the European multicenter I-KNOW database.
• Independent readers assessed ischemic lesion visibility on b0 and FLAIR images.
• Signal-intensity ratio was measured from segmented stroke lesions on b1000 images.

Main Results:

• The b1000-b0 mismatch identified patients within 4.5 hours of stroke onset with high positive predictive value (88.6%).
• Compared to DWI-FLAIR mismatch (gold standard), b1000-b0 mismatch showed high sensitivity (85.9%) and specificity (91.2%).
• A weak but significant correlation was found between b0 signal-intensity ratio and the delay between stroke onset and MRI.

Conclusions:

• The b1000-b0 mismatch is a potential alternative imaging biomarker for identifying ischemic stroke within 4.5 hours of onset.
• This method offers a high positive predictive value for acute stroke detection.
• The b1000-b0 mismatch may function as an accessible "tissue clock" in clinical practice.