In patients with acute basilar artery occlusion, baseline imaging modality (MRI vs CT) was not significantly associated with 90-day functional outcomes, and MRI was not associated with significant workflow delays compared to CT.
Key Findings
Results
Baseline imaging modality (MRI vs CT) was not significantly associated with 90-day favorable functional outcome (mRS 0-3) in patients with acute basilar artery occlusion.
Post hoc analysis of the ATTENTION trial with 340 total patients (CT: n=277; MRI: n=63)
OR 0.99, 95% CI 0.50-1.95; P=0.976 for the association between baseline imaging modality and 90-day mRS 0-3
The finding remained consistent across both the endovascular treatment and best medical management subgroups
The association between imaging modality and outcomes was also consistent across different time windows
Results
Baseline MRI assessment was not associated with significant workflow delays compared with CT in patients with acute basilar artery occlusion.
Time from stroke onset to randomization: mean difference of 5.23 minutes favoring CT, P=0.843
Time from stroke onset to arterial puncture: mean difference of 13.16 minutes favoring CT, P=0.701
Neither difference reached statistical significance, suggesting MRI does not meaningfully delay treatment initiation
Methods
The study population was heavily skewed toward CT as the baseline imaging modality, with CT used in the majority of patients.
Of 340 total patients, 277 (81.5%) underwent CT and 63 (18.5%) underwent MRI as baseline imaging
This reflects real-world clinical practice patterns in the ATTENTION trial centers
The imbalance in group sizes is a limitation of the post hoc observational design
Conclusions
The authors concluded that conventional CT imaging appears sufficient as a first-line tool for selecting acute BAO patients for treatment.
No evidence was found supporting the preferential use of MRI over CT as the primary imaging strategy for patient selection
The conclusion applied to both endovascular treatment and best medical management decision-making contexts
The findings were described as consistent across different time windows from stroke onset
What This Means
This research suggests that for patients experiencing a blockage of the basilar artery — a critical blood vessel supplying the back of the brain — the choice between MRI and CT scans for initial evaluation does not meaningfully affect patient outcomes. Using data from the ATTENTION clinical trial, researchers compared 277 patients who received CT scans and 63 who received MRI scans as their initial imaging. At 90 days, the odds of having a good functional outcome (meaning the patient was largely independent) were virtually identical between the two groups, and this held true whether patients received clot-removal procedures or medication alone.
A common concern about using MRI in emergencies is that it takes longer than CT, potentially delaying life-saving treatment. This study found that MRI did not cause meaningful delays: the difference in time from stroke onset to randomization was only about 5 minutes, and the difference in time to the clot-removal procedure was about 13 minutes — neither of which was statistically significant. These small differences are unlikely to be clinically important in most cases.
This research suggests that hospitals do not need to prioritize MRI over CT when rapidly evaluating patients with suspected basilar artery occlusion. Since CT scanners are more widely available, faster to access, and less expensive, these findings support CT as a practical and effective first-line imaging tool for this serious condition. However, the study is a post hoc analysis with an uneven group size, so the findings should be interpreted with caution and confirmed in future prospective studies.
Gao F, Nguyen T, Wang A, Li R, Xu P, Chen Y, et al.. (2026). Magnetic resonance imaging vs computed tomography for baseline imaging evaluation in acute basilar artery occlusion.. Journal of neurology. https://doi.org/10.1007/s00415-026-14159-4