MRI-Based and CT-Based Thrombolytic Therapy in Acute Stroke Within and Beyond Established Time Windows

Abstract

Background and Purpose-The use of intravenous thrombolysis is restricted to a minority of patients by the rigid 3-hour time window. This window may be extended by using modern imaging-based selection algorithms. We assessed safety and efficacy of MRI-based thrombolysis within and beyond 3 hours compared with standard CT-based thrombolysis. Methods-Five European stroke centers pooled the core data of their CT-and MRI-based prospective thrombolysis databases. Safety outcomes were predefined as symptomatic intracranial hemorrhage and mortality. Primary efficacy outcome was a favorable outcome (modified Rankin Scale 0 to 1). We performed univariate and multivariate analyses for all end points, including age, National Institutes of Health Stroke Scale, treatment group (CT Ͻ3 hours, MRI Ͻ3 hours and Ͼ3 hours), and onset to treatment time as variables. Results-A total of 1210 patients were included (CT Ͻ3 hours: Nϭ714; MRI Ͻ3 hours: Nϭ316; MRI Ͼ3 hours: Nϭ180).Median age, National Institutes of Health Stroke Scale, and onset to treatment time were 69, 67, and 68.5 years (Pϭ0.66); 12, 13, and 14 points (Pϭ0.019); and 130, 135, and 240 minutes (PϽ0.001). Symptomatic intracranial hemorrhage rates were 5.3%, 2.8%, and 4.4% (Pϭ0.213); mortality was 13.7%, 11.7%, and 13.3% (Pϭ0.68). Favorable outcome occurred in 35.4%, 37.0%, and 40% (Pϭ0.51). Age and National Institutes of Health Stroke Scale were independent predictors for all safety and efficacy outcomes. The overall use of MRI significantly reduced symptomatic intracranial hemorrhage (OR: 0.520, 95% CI: 0.270 to 0.999, Pϭ0.05). Beyond 3 hours, the use of MRI significantly predicted a favorable outcome (OR: 1.467; 95% CI: 1.017 to 2.117, Pϭ0.040). Within 3 hours and for all secondary end points, there was a trend in favor of MRI-based selection over standard Ͻ3-hour CT-based treatment. Conclusion-Despite significantly longer time windows and significantly higher baseline National Institutes of Health Stroke Scale scores, MRI-based thrombolysis is safer and potentially more efficacious than standard CT-based thrombolysis.

The Performance of MRI-Based Cerebral Blood Flow Measurements in Acute and Subacute Stroke Compared With 15O-Water Positron Emission Tomography

“…This is a relevant finding taking into account that a volumetric difference of 20% between DWI and PWI volume is commonly postulated for mismatch definition. 4,7,10,11,48 This methodical problem has already been addressed in previous ROI-based studies of a small patient sample 39,42 and in healthy volunteers. 38 These studies, like in our sample, found good agreement of ROI values on an individual basis.…”

“…[2][3][4] The hypoperfused but still viable tissue is the target for early reperfusion in acute stroke. The so-called "penumbra" is characterized by specific metabolic patterns and can be detected by positron emission tomography (PET).…”

Regional and temporal variations in tissue sodium concentration during the acute stroke phase

“…Indeed, it has been shown that thrombolytic treatment outcomes are improved in patients selected based on an MRI diagnosis (2). The MR technique, which is currently available for identifying patients likely to benefit from thrombolytic treatment is the so-called perfusion-diffusion mismatch, where the mismatch between the ischemically injured tissue and hypoperfused tissue is determined from diffusion-and perfusion-weighted 1 H-MRI, respectively (3).…”

Clinical profile of patients with acute ischemic stroke receiving intravenous thrombolysis (rtPA-alteplase)

“…7 Schellinger PD et al compared "MRI based thrombolysis" with "CT based thrombolysis". 8 They concluded that "MRI based thrombolysis" was more effective and safer than the "CT based thrombolysis".…”