- Design
- Post hoc analysis of a randomised trial (ATTENTION)
- Population
- 340 patients with acute basilar artery occlusion; 277 CT, 63 MRI
- Primary outcome
- Modified Rankin 0–3 at 90 days
- Effect
- OR 0.99 (95% CI 0.50–1.95) for MRI vs CT; no significant difference in time to puncture
A post hoc analysis of the ATTENTION trial, which randomised patients with acute basilar artery occlusion to thrombectomy or best medical care, compared those whose baseline imaging was CT (277) with those who had MRI (63).
Imaging modality was not associated with good 90-day outcome, defined as modified Rankin 0 to 3 (OR 0.99, 95% CI 0.50–1.95), in the whole cohort or in either treatment arm, and the finding held across time windows. MRI did not significantly delay randomisation or groin puncture, though the comparison is small.
MRI shows posterior circulation infarction better than CT, and some centres prefer it for selecting patients for thrombectomy. This analysis does not support waiting for MRI when CT and CT angiography are available. It was not randomised by imaging, so the choice of MRI may have reflected patient or centre factors, and the MRI group was small. In Indian stroke-ready hospitals, where MRI out of hours is often not available, the result supports proceeding on CT.
- Do not delay thrombectomy decisions in suspected basilar occlusion to obtain MRI when CT and CT angiography are available.
- Use CT angiography to confirm basilar occlusion as part of the first imaging run.
- Consider MRI where it is immediately available and will not delay treatment.
- Keep the clinical picture central: reduced consciousness or vertigo with long-tract signs should prompt vessel imaging.
Why it matters
Waiting for MRI in basilar occlusion costs time that this analysis suggests buys nothing.
Don't overread it
Imaging was not randomised, and the MRI group was small.
The statistics, in plain English
An odds ratio of 0.99 means outcomes were almost identical with either imaging. But the interval from 0.50 to 1.95 is wide because only 63 patients had MRI, so a modest difference either way cannot be excluded.
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