Delayed treatment outcomes compare with early CT thrombolysis if diffusion-perfusion mismatch is present
MRI-assisted thrombolysis is as good as and perhaps better than CT-assisted thrombolysis, and it may be particularly valuable for patients treated outside of the prescribed 3-hour treatment window after stroke onset.1 These findings were part of a large multicenter European study reported at the 2007 International Stroke Conference in San Francisco in February by Peter D. Schellinger, MD, PhD, a professor of neurology at the University of Erlangen in Germany.
The study, which compared standard CT-based thrombolysis (within the 3-hour treatment window) with MRI-based thrombolysis within and outside the 3-hour window, included 1210 patients from 5 stroke centers in Germany and Spain. CT-assisted thrombolysis within 3 hours of stroke onset was performed in 714 patients, MRI-assisted thrombolysis within 3 hours after stroke was performed in 322 patients, and MRI-assisted thrombolysis after 3 hours of stroke onset was performed in 174 patients. The mean onset to treatment time was 130, 136, and 279 minutes, respectively.
Despite their significantly longer treatment window and higher baseline National Institutes of Health Stroke Scale scores, patients who received MRI-assisted thrombolysis more than 3 hours after stroke onset fared just as well as or better than patients receiving CT-assisted thrombolysis within 3 hours of stroke onset. Rates of symptomatic intracranial hemorrhage (ICH) for the 3 approaches were 5.3%, 3.1%, and 4.0%, respectively. Mortality rates were 13.7%, 12.4%, and 12.1%, respectively. Favorable outcomes in terms of effectiveness and safety were seen in 35.6%, 35.7%, and 42% of patients, respectively.
Schellinger and coinvestigators from the University of Erlangen and the University of Heidelberg have been looking at the value of MRI-assisted thrombolysis for several years. The study presented at the International Stroke Conference was a recapitulation of a recently published study by Schellinger and coresearchers of 382 patients that specifically looked at the effectiveness and safety of MRI-assisted thrombolysis outside of the 3-hour treatment window after stroke onset.2
The investigators explained in the article that patients are treated at their institutions only if a perfusion-diffusion MRI mismatch (perfusion exceeding diffusion) is apparent. No cutoff for age or stroke severity is applied, but thrombolysis is contraindicated in patients with a diffusion-weighted MRI lesion covering more than 50% of the middle cerebral artery.
Seventy patients received MRI-assisted thrombolysis after 3 hours of stroke onset, 103 received it within 3 hours of stroke onset, and 209 patients received CT-assisted thrombolysis within 3 hours of stroke onset. Incidence of ICH was lower in the MRI-treated groups than in the CT-treated group, although the investigators noted that ICH was more common among older patients (mean age 75 years versus mean age 71 years) and among patients with higher stroke severity scores. Increased age and stroke severity were strong predictors of worse outcomes.
At 90 days, favorable outcomes were seen in 41% of patients receiving MRI-assisted thrombolysis outside of the 3-hour treatment window, 33% receiving MRI-assisted thrombolysis within the treatment window, and 38% receiving CT-assisted thrombolysis. Mortality also was lower among patients treated with MRI compared with those treated with CT.
The investigators came to the same conclusion as the investigators involved in the larger study, that MRI-assisted thrombolysis is at least as good as CT-assisted thrombolysis and of particular value to patients treated outside the prescribed 3-hour window. They added that a good outcome in relation to thrombolytic therapy is more dependent on patient selection than on time to treatment.
Stay at the forefront of radiology with the Diagnostic Imaging newsletter, delivering the latest news, clinical insights, and imaging advancements for today’s radiologists.
The Reading Room Podcast: A Closer Look at Remote MRI Safety, Part 2
July 25th 2025In the second of a multi-part podcast episode, Emanuel Kanal, M.D. and Tobias Gilk, MRSO, MRSE, share their perspectives on remote MRI safety protocols for ensuring screening accuracy and adherence to conditional implant guidelines as well as a rapid and effective response to adverse events.
Study Reveals Significant Prevalence of Abnormal PET/MRI and Dual-Energy CT Findings with Long Covid
July 22nd 2025In a prospective study involving nearly 100 patients with Long Covid, 57 percent of patients had PET/MRI abnormalities and 90 percent of the cohort had abnormalities on dual-energy CT scans.
The Reading Room Podcast: Current and Emerging Insights on Abbreviated Breast MRI, Part 2
July 23rd 2025In the second part of a multi-part podcast episode, Stamatia Destounis, MD, Emily Conant, MD and Habib Rahbar, MD, discuss key sequences for abbreviated breast MRI and how it stacks up to other breast cancer screening modalities.
Stroke MRI Study Assesses Impact of Motion Artifacts Upon AI and Radiologist Lesion Detection
July 16th 2025Noting a 7.4 percent incidence of motion artifacts on brain MRI scans for suspected stroke patients, the authors of a new study found that motion artifacts can reduce radiologist and AI accuracy for detecting hemorrhagic lesions.