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.

INTRODUCTION: 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.
METHODS: 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).
RESULTS: 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).
CONCLUSION: 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.