Background Clinical-diffusion mismatch (CDM) between stroke severity and volume of diffusion-weighted imaging (DWI) lesions seems to predict penumbra. The Alberta Stroke Program Early CT Score on DWI (DWI ASPECTS) is a simple score for identifying ischaemic lesions. The authors examined whether CDM using DWI ASPECTS can predict neurological improvement in patients with acute stroke treated with intravenous tissue plasminogen activator (t-PA).

Methods The authors enrolled consecutive patients with anterior circulation stroke treated with intravenous t-PA. The authors calculated a cut-off value for CDM using DWI ASPECTS. After excluding a group of patients with mild symptoms (National Institutes of Health Stroke Scale (NIHSS) score <8), the authors divided the patients into two groups by presence or not of CDM (a positive group (P-CDM) and a negative group (N-CDM)). The authors then compared clinical characteristics including NIHSS score and modified Rankin Scale at 90 days after intravenous t-PA.

Results Seventy-one patients (male 41, mean age 74 years) were enrolled. DWI ASPECTS was linearly related to DWI lesion volume. The authors defined CDM as NIHSS scores ≥8 and DWI ASPECTS ≥7. The P-CDM group had 35 patients (61%) and the N-CDM group 22 patients (39%). NIHSS scores on admission were 15 (median) in P-CDM and 20 in N-CDM (p=0.004). NIHSS scores after intravenous t-PA improved in P-CDM but were unchanged in N-CDM (7 vs 20 at 7 days, p=0.033 on ANOVA). A favourable outcome at 90 days, defined as modified Rankin scale 0–3, was found in 46% of P-CDM patients and 14% of N-CDM patients (p=0.020).

Conclusion CDM determined using DWI ASPECTS may be associated with neurological improvement in patients treated with intravenous t-PA.