DIFFUSION-WEIGHTED MRI IN ACUTE SUBCORTICAL INFARCTION

Background and Purpose-Conventional imaging lacks sensitivity and spec ificity for the detection of early subcortical cerebral infarction. Th e purposes of our study were (1) to determine the accuracy of diffusio n-weighted (DW) MRI for early subcortical infarction and (2) to determ ine the efficacy of DW MRI for differentiating acute from nonacute sub cortical infarctions when conventional MR demonstrates multiple infarc tions. Methods-Thirty-nine patients with clinically diagnosed acute su bcortical infarction and 17 control subjects were imaged with both con ventional and DW MRI from 7 hours to 4 days (mean, 2.0 days) after ons et of symptoms. All images were read blinded to specific clinical find ings. In all cases, the precise neuroanatomic locations of lesions wer e noted. These lesions were subsequently correlated by an experienced stroke neurologist to determine whether their locations correlated to the patients' symptoms. Results-The accuracy of DW MRI for acute subco rtical infarction was 94.6%. In 4 of 39 cases, the acute infarction wa s not detected on conventional MRI. In 24 of 39 cases, conventional MR I showed the acute lesion as well as multiple other subcortical lesion s. In each of these 24 cases, the DW MRI showed a single lesion to be acute, and in all 24 cases, that lesion corresponded to the patients' acute symptoms. Conclusions-DW MRI has very high accuracy for acute su bcortical infarction and can differentiate acute from nonacute lesions . These data have significant implications in guiding patient manageme nt and patient selection for clinical trials.