Background and Purpose—MRI is useful for detecting early ischemic lesions before administration of tissue plasminogen activator in patients with hyperacute ischemic stroke. However, it is unclear whether early ischemic change seen on diffusion-weighted imaging (DWI) can be used to predict patient outcomes.

Methods—Consecutive patients with anterior circulation ischemic stroke treated with tissue plasminogen activator within 3 hours of stroke onset were prospectively studied. The National Institutes of Health Stroke Scale score was obtained before and 7 days after tissue plasminogen activator administration. MRI, including DWI, was done before tissue plasminogen activator thrombolysis. The relationship between the DWI Alberta Stroke Programme Early CT Score (ASPECTS) and patients’ outcomes was assessed.

Results—The subjects consisted of 49 consecutive patients with stroke (27 males; mean age, 72.9±10.3 years). The median (range) of the baseline DWI ASPECTS value was 9 (3–10). Dramatic improvement was seen in one of 8 patients with an ASPECTS 5 compared with 21 of 41 patients with a DWI ASPECTS >5 (P=0.0592). On the other hand, worsening was noted more frequently in patients with a DWI ASPECTS 5 (3 of 8 patients) than in patients with an ASPECTS >5 (4 of 41 patients; P=0.0753). Bad outcome was seen more frequently in patients with a DWI ASPECTS 5 (6 of 8 patients) than in patients with a DWI ASPECTS >5 (2 of 41 patients; P<0.0001). Multivariate logistic regression analysis demonstrated that a DWI ASPECTS 5 was the only independent predictor of a bad outcome (OR, 33.4; 95% CI, 2.7 to 410.8; P=0.0062).

Conclusion—DWI ASPECTS appears to be a reliable tool for predicting bad outcome. Patients with a DWI ASPECTS >5 should be considered eligible for tissue plasminogen activator therapy.