Failed Recovery from Thrombolysis Is Predicted by the Initial Diffusion Weighted Imaging Lesion

<i>Background:</i> The clinical response to systemic thrombolysis with recombinant tissue plasminogen activator (rtPA) is thought to depend on an early recanalization. We sought to investigate the effect of early recanalization on stroke lesion development as assessed with magnetic resonance imaging (MRI). <i>Methods:</i> Thirty-seven consecutive stroke patients (66 ± 13 years) treated with systemic thrombolysis with rtPA and tirofiban were grouped according to successful or failed recanalization as assessed on angiographic imaging. Infarct lesions were determined volumetrically in MRI prior to treatment and after 4 days. <i>Results:</i> Patients were severely affected (median National Institutes of Health Stroke Scale 14) and had significantly larger perfusion (PWI) than diffusion weighted imaging (DWI) lesion volumes. Ten patients with failed recanalization of the internal carotid or the middle cerebral artery did not improve. Their PWI and DWI lesion volumes were larger and the apparent diffusion coefficient more depressed than in the 27 patients with significant improvement and successful recanalization (p < 0.001). The DWI lesion volumes increased profoundly in the patients with failed recanalization (p < 0.001) but only little in the patients with successful recanalization. Multivariate regression analysis showed a relation of the initial DWI lesion volumes to the DWI lesion volumes at follow-up and the neurological recovery. <i>Conclusions:</i> The ischemic brain damage was particularly severe in patients with no recanalization already before systemic thrombolysis and predicted further lesion growth and failed recovery.