Impact of diffusion-weighted MRI-measured initial cerebral infarction volume on clinical outcome in acute stroke patients with middle cerebral artery occlusion treated by thrombolysis

Abstract

Magnetic resonance imaging (MRI) may help identify acute stroke patients with a higher potential benefit from thrombolytic therapy. The aim of our study was to assess the correlation between initial cerebral infarct (CI) volume (quantified on diffusion-weighted MRI) and the resulting clinical outcome in acute stroke patients with middle cerebral artery (MCA) (M(1-2) segment) occlusion detected on MRI angiography treated by intravenous/intraarterial thrombolysis. Initial infarct volume (V(DWI-I) ) was retrospectively compared with neurological deficit evaluated using the NIH stroke scale on admission and 24 h later, and with the 90-day clinical outcome assessed using the modified Rankin scale in a series of 25 consecutive CI patients. The relationship between infarct volume and neurological deficit severity was assessed and, following the establishment of the maximum V(DWI-I) still associated with a good clinical outcome, the patients were divided into two groups (V(DWI-I) < or =70 ml and >70 ml). V(DWI-I) ranged from 0.7 to 321 ml. The 24-h clinical outcome improved significantly (P=0.0001) in 87% of patients with a V(DWI-I) < or =70 ml (group 1) and deteriorated significantly (P=0.0018) in all patients with a V(DWI-I) >70 ml (group 2). The 90-day mortality was 0% in group 1 and 71.5% in group 2. The 90-day clinical outcome was significantly better in group 1 than in group 2 (P=0.026). Clinical outcome could be predicted from initial infarct volume quantified by MRI-DWI in acute CI patients with MCA occlusion treated by intravenous/intraarterial thrombolysis. Patients with a V(DWI-I) < or =70 ml had a significantly better outcome.