Efficacy of systemic thrombolysis within 4.5 h from stroke symptom onset: a single-centre clinical and diffusion-perfusion 3T MRI study.

Purpose The efficacy of thrombolytic treatment with recombinant tissue plasminogen activator (rt-PA) within 3h from stroke onset has been extensively supported by randomised placebo-controlled multicentre trials. In our single-centre study, we investigated the efficacy of intra- venous (IV) administration of rt-PA within 4.5 h of stroke onset, in terms of clinical and radiological outcome, using a 3T magnetic resonance (MR) scanner in a cohort of patients similar to that of multicentre clinical trials.Materials and methods Consecutive patients treated with IV rt-PA were compared with an historical cohort of untreated patients (controls). Inclusion criteria were: (1) infarction of the middle cerebral artery territory, (2) eligi- bility for IV rt-PA treatment, and (3) 3T perfusion- and diffusion-weighted MR imaging and MR angiography performed within 4.5 h and repeated after 5-7 days. Stroke severity was assessed with the National Institutes of Health Stroke Scale (NIHSS). Growth of the DWI lesion, saved hypoperfused tissue, and clinical outcome was assessed and compared in treated patients and controls.Results Forty-three patients treated with rt-PA and 69 controls were eligible for the analysis. Treated patientsshowed higher percentages of saved hypoperfused tissue (75 vs. 40%; p = 0.009), vessel recanalisation (65 vs.27.5%; p = 0.003), and haemorrhagic transformation (21 vs. 7%; p = 0.004), without any clinically significant haemorrhages. Furthermore, treated patients had a signifi- cant improvement of NIHSS at 24 h (p\0.001), at dis- charge (p B0.001), and at the 3-month clinical evaluation (p\0.001), while similar rates of both treated patients and controls achieved a 3-month modified Rankin scale B2 (62 and 65%; p = 0.7).Conclusion Treatment with IV rt-PA within 4.5 h of stroke onset preserves a significant amount of brain tissue from final infarction, and increases the possibility of early and late clinical improvement. ©Italian Society of Medical Radiology 2014.