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High-b-value diffusion-weighted MR imaging of hyperacute ischemic stroke at 1.5T
Hyun Jeong Kim1, Choong Gon Choi, Deok Hee Lee
1Department of Radiology, Asan Medical Center, University of Ulsan, College of Medicine, 388-1 Poongnap Dong, Songpa-Gu, Seoul, 138-736, Korea.
AJNR. American Journal of Neuroradiology
|February 15, 2005
Summary
Diffusion-weighted (DW) imaging with b = 2000 s/mm(2) is superior to b = 1000 s/mm(2) for detecting hyperacute ischemic stroke within 6 hours. Higher b-value images improve lesion detection and size estimation in early stroke diagnosis.
Area of Science:
- Radiology
- Neuroimaging
- Stroke Diagnosis
Background:
- Diffusion-weighted (DW) imaging is crucial for detecting hyperacute ischemic stroke.
- Higher b-values in DW imaging theoretically enhance lesion conspicuity.
Purpose of the Study:
- To compare the efficacy of DW imaging at b = 2000 s/mm(2) versus b = 1000 s/mm(2) for detecting and quantifying diffusion changes in early ischemic stroke.
- To evaluate diagnostic performance within 6 hours of stroke onset.
Main Methods:
- A comparative study involving 94 patients with suspected hyperacute ischemic stroke within 6 hours of onset.
- Qualitative analysis of lesion conspicuity and extent by three observers.
- Quantitative analysis of lesion volume, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) in 34 patients.
Main Results:
- DW imaging at b = 2000 s/mm(2) demonstrated higher sensitivity (98%) and specificity (100%) compared to b = 1000 s/mm(2) (94% and 100%).
- Lesions were more conspicuous and larger on b = 2000 images.
- Quantitative analysis showed a 47% increase in mean lesion volume and a 23% increase in CNR with b = 2000 s/mm(2).
Conclusions:
- DW imaging at b = 2000 s/mm(2) offers significant advantages over b = 1000 s/mm(2) for detecting and assessing the extent of diffusion changes in hyperacute ischemic stroke.
- This higher b-value technique improves diagnostic accuracy in the critical early hours post-stroke.