Brain Injury Visible on Early MRI After Subarachnoid Hemorrhage Might Predict Neurological Impairment and Functional Outcome

Background: In subarachnoid hemorrhage (SAH), brain injury visible within 48 h of onset may impact on admission neurological disability and 3-month functional outcome. With volumetric MRI, we measured the volume of brain injury visible after SAH, and assessed the association with admission clinical grade and 3-month functional outcome. Methods: Retrospective cohort study conducted in the Neurocritical Care Division, Columbia University Medical Center, New York, USA. On brain MRI acquired within 48 h of SAH-onset and before aneurysm-securing (n = 27), two blinded readers measured DWI and FLAIR-lesion volumes using semi-automated, computer segmentation software. Results: Compared to post-resuscitation Hunt–Hess grade 1–3 (70 %), high-grade patients (30 %) had higher lesion volumes on DWI (34 ml [IQR: 0–64] vs. 2 ml [IQR: 0.5–7], P = 0.02) and on FLAIR (81 ml [IQR: 24–127] vs. 3 ml [IQR: 0–27], P = 0.02). On DWI, each 10 ml increase in lesion volume was associated with a 101 %-increase in the odds of presenting with 1 grade more in the Hunt–Hess scale (aOR 2.01, 95 % CI 1.10–3.68, P = 0.02), but was not significantly associated with 3-month outcome. On FLAIR, each 10 ml increase in lesion volume was associated with 34 % higher odds of a 1-point increase on the Hunt–Hess scale (aOR 1.34, 95 % CI 1.06–1.68, P = 0.01) and 139 % higher odds of a 1-point increase on the 3-month mRS (aOR 2.39, 95 % CI 1.13–5.07, P = 0.02). Conclusion: The volume of brain injury visible on DWI and FLAIR within 48 h after SAH is proportional to neurological impairment on admission. Moreover, FLAIR-imaging implicates chronic brain injury—predating SAH—as potentially relevant cause of poor functional outcome.