In this small, retrospective, hypothesis-generating cohort, HALF-IT positivity (acute infarction of ≥50% of any brainstem section on MRI) was associated with worse 90-day functional outcomes after EVT for BAO, and prospective validation in larger cohorts is required before the score can inform treatment decisions.
Of 37 patients with acute BAO treated with EVT, 23 were HALF-IT negative and 14 were HALF-IT positive.
HALF-IT positive patients had a significantly lower rate of favorable 90-day outcome (mRS 0-3) than HALF-IT negative patients.
HALF-IT positive status remained associated with a lower rate of 90-day mRS 0-3 after multivariable adjustment.
Safety events were numerically higher in the HALF-IT positive group, but the differences were not statistically significant.
The two groups differed substantially at baseline in age, presenting NIHSS, and intravenous thrombolysis exposure, but not in stroke etiology or basilar occlusion level.
The authors characterize the findings as hypothesis-generating owing to the small, retrospective design and call for prospective validation.
Basilar artery occlusion is a severe type of stroke in which a major artery supplying the brainstem is blocked. Doctors use several tools to decide who should get clot-removal procedures (thrombectomy), but these tools have multiple tiers, can be scored differently by different readers, and have had limited testing. This study tested a simpler tool, the HALF-IT score, which asks one yes/no question on MRI: is at least half of any section of the brainstem already damaged by the stroke? The researchers reviewed 37 patients treated at four stroke centers between 2021 and 2025. Among the 14 patients with half or more of a brainstem section already infarcted, only 14.3% had a favorable outcome (mRS 0-3) at 90 days, versus 68.2% of the 23 patients without that extent of damage. The association persisted after statistical adjustment for age, stroke severity, timing, clot-busting drug use and degree of reperfusion. Deaths and brain bleeding were numerically more common in the positive group, but the differences were not statistically significant. This research suggests that a simple brainstem MRI check could help identify patients less likely to do well after thrombectomy. However, the study was very small and retrospective, the groups differed in age and stroke severity, and the statistical estimates were imprecise. The authors stress that larger prospective studies are needed before this score should be used to guide treatment decisions.
Jones A, Tariq Z, Ashouri Y, Chaudhari A, AlMajali M, Ezzeldin M, et al.. (2026). The HALF-IT score: proposing a simplified mechanical thrombectomy triage tool for basilar artery occlusion.. Frontiers in neurology. https://doi.org/10.3389/fneur.2026.1915436