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Updated: Jun 16, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
Pretreatment diffusion- and perfusion-MR lesion volumes have a crucial influence on clinical response to stroke
Mark W Parsons1, Soren Christensen, Patrick McElduff
1Department of Neurology, John Hunter Hospital, University of Newcastle, Newcastle, New South Wales, Australia. mark.parsons@hnehealth.nsw.gov.au
Abstract:
We hypothesized that pretreatment magnetic resonance imaging (MRI) diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) lesion volumes may have influenced clinical response to thrombolysis in the Echoplanar Imaging Thrombolytic Evaluation Trial (EPITHET). In 98 patients randomized to intravenous (IV) tissue plasminogen activator (tPA) or placebo 3 to 6 h after stroke onset, we examined increasing acute DWI and PWI lesion volumes (Tmax-with 2-sec delay increments), and increasing PWI/DWI mismatch ratios, on the odds of both excellent (modified Rankin Scale (mRS): 0 to 1) and poor (mRS: 5 to 6) clinical outcome. Patients with very large PWI lesions (most had internal carotid artery occlusion) had increased odds ratio (OR) of poor outcome with IV-tPA (58% versus 25% placebo; OR=4.13, P=0.032 for Tmax +2-sec volume >190 mL). Excellent outcome from tPA treatment was substantially increased in patients with DWI lesions <18 mL (77% versus 18% placebo, OR=15.0, P<0.001). Benefit from tPA was also seen with DWI lesions up to 25 mL (69% versus 29% placebo, OR=5.5, P=0.03), but not for DWI lesions >25 mL. In contrast, increasing mismatch ratios did not influence the odds of excellent outcome with tPA. Clinical responsiveness to IV-tPA, and stroke outcome, depends more on baseline DWI and PWI lesion volumes than the extent of perfusion-diffusion mismatch.
Insights
Pretreatment MRI lesion volumes, specifically diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI), significantly influence stroke treatment outcomes with intravenous tissue plasminogen activator (IV-tPA). Larger DWI lesion volumes predict poorer outcomes, while smaller volumes indicate better response to IV-tPA.
Area of Science:
- Neurology
- Radiology
- Stroke Medicine
Background:
- Thrombolysis with intravenous tissue plasminogen activator (IV-tPA) is a critical treatment for acute ischemic stroke.
- Predicting clinical response to IV-tPA remains a challenge, necessitating better understanding of factors influencing outcomes.
Purpose of the Study:
- To investigate whether pretreatment magnetic resonance imaging (MRI) diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) lesion volumes, and their mismatch, predict clinical outcomes in patients receiving IV-tPA.
- To analyze the impact of DWI and PWI lesion volumes on excellent (modified Rankin Scale [mRS] 0-1) and poor (mRS 5-6) outcomes.
Main Methods:
- Analysis of 98 patients from the Echoplanar Imaging Thrombolytic Evaluation Trial (EPITHET) randomized to IV-tPA or placebo.
- Examination of acute DWI and PWI lesion volumes (Tmax with 2-sec delay increments) and PWI/DWI mismatch ratios.
- Statistical analysis of lesion volumes and mismatch ratios against odds of excellent and poor clinical outcomes.
Main Results:
- Very large PWI lesions were associated with increased odds of poor outcome with IV-tPA (OR=4.13, P=0.032 for Tmax +2-sec volume >190 mL).
- Excellent outcomes from IV-tPA were significantly increased in patients with DWI lesions <18 mL (OR=15.0, P<0.001) and seen up to 25 mL (OR=5.5, P=0.03).
- Increasing PWI/DWI mismatch ratios did not significantly influence the odds of excellent outcome with IV-tPA.
Conclusions:
- Baseline DWI and PWI lesion volumes are more critical determinants of clinical response to IV-tPA than the perfusion-diffusion mismatch extent.
- These findings highlight the importance of baseline lesion volume assessment in predicting stroke outcomes following thrombolysis.
