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Updated: Jul 13, 2026
Optimized Management of Endovascular Treatment for Acute Ischemic Stroke
Published on: January 18, 2018
MRI-based and CT-based thrombolytic therapy in acute stroke within and beyond established time windows: an analysis
Peter D Schellinger1, Götz Thomalla, Jens Fiehler
1Department of Neurology, University of Erlangen, Schwabachanlage 6, D-91054 Erlangen, Germany. Peter.Schellinger@uk-erlangen.de
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 <3 hours, MRI <3 hours and >3 hours), and onset to treatment time as variables.
Results:
A total of 1210 patients were included (CT <3 hours: N=714; MRI <3 hours: N=316; MRI >3 hours: N=180). Median age, National Institutes of Health Stroke Scale, and onset to treatment time were 69, 67, and 68.5 years (P=0.66); 12, 13, and 14 points (P=0.019); and 130, 135, and 240 minutes (P<0.001). Symptomatic intracranial hemorrhage rates were 5.3%, 2.8%, and 4.4% (P=0.213); mortality was 13.7%, 11.7%, and 13.3% (P=0.68). Favorable outcome occurred in 35.4%, 37.0%, and 40% (P=0.51). 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, P=0.05). Beyond 3 hours, the use of MRI significantly predicted a favorable outcome (OR: 1.467; 95% CI: 1.017 to 2.117, P=0.040). Within 3 hours and for all secondary end points, there was a trend in favor of MRI-based selection over standard <3-hour CT-based treatment.
Conclusions:
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.
Insights
Magnetic Resonance Imaging (MRI) enables safer and more effective thrombolysis for stroke patients beyond the traditional 3-hour window. This advanced imaging approach improves outcomes compared to standard CT scans, expanding treatment eligibility.
Area of Science:
- Neurology
- Radiology
- Emergency Medicine
Background:
- Intravenous thrombolysis for acute ischemic stroke is limited by a strict 3-hour time window.
- Advanced imaging techniques, such as MRI, can potentially identify suitable patients beyond this conventional timeframe.
- Current selection protocols often rely on standard CT, which may not fully capture the extent of brain tissue at risk.
Purpose of the Study:
- To assess the safety and efficacy of MRI-guided thrombolysis compared to CT-guided thrombolysis.
- To evaluate outcomes for thrombolysis administered within and beyond the 3-hour window using MRI selection.
- To determine if MRI improves patient selection for thrombolysis in acute stroke.
Main Methods:
- A pooled analysis of prospective thrombolysis databases from five European stroke centers.
- Inclusion of 1210 patients, categorized by treatment group: CT <3 hours, MRI <3 hours, and MRI >3 hours.
- Analysis of safety outcomes (symptomatic intracranial hemorrhage, mortality) and efficacy (favorable outcome on modified Rankin Scale).
Main Results:
- MRI-based thrombolysis demonstrated reduced symptomatic intracranial hemorrhage rates overall (P=0.05).
- Beyond 3 hours, MRI significantly predicted a favorable outcome (OR: 1.467, P=0.040).
- Trends favored MRI selection for improved outcomes within 3 hours compared to CT.
Conclusions:
- MRI-guided thrombolysis is safer and potentially more efficacious than standard CT-based treatment.
- MRI expands the therapeutic window for thrombolysis, improving outcomes in acute ischemic stroke.
- Imaging-based selection algorithms are crucial for optimizing thrombolysis in stroke patients.
