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[Diffusion-weighted MRI detectability of acute cerebral ischemia: comparison with eventual infarction]
T Inoue1, H Shimizu, S Fujiwara
1Department of Neurosurgery, Tohoku University School of Medicine, Sendai, Japan.
Abstract:
To clarify the clinical significance of diffusion-weighted magnetic resonance imaging (DWI) hyperintensity in acute cerebral ischemia, 34 patients were investigated with cerebral ischemia that had lasted no more than 8 hours. Either a spin echo sequence with navigator echo (n = 21) or an echo planar sequence (n = 13) was used for DWI using 1.5 tesla magnet. The eventual infarction was judged from T2-weighted image (T2 WI) or CT performed 2-12 days after the onset and was classified into cortical (n = 24) or perforating artery (n = 10) area. The eventual infarction was compared in size with the acute DWI finding and expressed as larger, same or smaller. Thirty patients showed ischemic hyperintensity lesions on acute DWI (6 patients on T2 WI). In cortical artery areas, the eventual infarction was same as hyperintensity area of acute DWI in 15 cases, larger in 8 cases, smaller in 2 cases. In perforating artery areas, the eventual infarction was same as hyperintensity area of acute DWI in 8 cases, and larger in 2 cases. These results suggest that in the perforating artery areas, the acute DWI hyperintensity is a good predictor of the eventual infarction and that in cortical artery areas, dynamic ischemic process may continue for hours before resulting in the eventual infarction.
Insights
Diffusion-weighted imaging (DWI) hyperintensity accurately predicts final infarction size in acute cerebral ischemia perforating artery areas. In cortical areas, DWI findings suggest a dynamic ischemic process continuing for hours.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Acute cerebral ischemia requires prompt and accurate assessment.
- Diffusion-weighted magnetic resonance imaging (DWI) is a key technique for detecting early ischemic changes.
Purpose of the Study:
- To evaluate the clinical significance of DWI hyperintensity in predicting the final infarct size in acute cerebral ischemia.
- To compare the predictive value of DWI in cortical versus perforating artery territories.
Main Methods:
- 34 patients with acute cerebral ischemia (symptoms < 8 hours) underwent DWI using a 1.5 tesla magnet.
- Two DWI sequences were employed: spin echo with navigator echo (n=21) and echo planar (n=13).
- Final infarcts were assessed using T2-weighted images or CT scans 2-12 days post-onset and classified by arterial territory (cortical or perforating).
Main Results:
- Thirty patients (88%) showed ischemic hyperintensity on acute DWI; only 6 were visible on T2-weighted images.
- In perforating artery areas, DWI hyperintensity size correlated well with eventual infarct size (same in 8/10, larger in 2/10).
- In cortical artery areas, 15/24 infarcts matched DWI size, but 8/24 were larger, suggesting continued evolution.
Conclusions:
- Acute DWI hyperintensity is a reliable predictor of final infarct size in perforating artery territories of acute cerebral ischemia.
- In cortical artery territories, DWI hyperintensity may underestimate the final infarct size due to ongoing ischemic processes.
- DWI is crucial for early detection and size estimation of ischemic stroke, with territory-specific interpretation nuances.