Brain injury visible on early MRI after subarachnoid hemorrhage might predict neurological impairment and functional outcome.

Abstract

In subarachnoid hemorrhage (SAH), brain injury visible within 48h 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. Retrospective cohort study conducted in the Neurocritical Care Division, Columbia University Medical Center, New York, USA. On brain MRI acquired within 48h of SAH-onset and before aneurysm-securing (n=27), two blinded readers measured DWI and FLAIR-lesion volumes using semi-automated, computer segmentation software. Compared to post-resuscitation Hunt-Hess grade 1-3 (70%), high-grade patients (30%) had higher lesion volumes on DWI (34ml [IQR: 0-64] vs. 2ml [IQR: 0.5-7], P=0.02) and on FLAIR (81ml [IQR: 24-127] vs. 3ml [IQR: 0-27], P=0.02). On DWI, each 10ml 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 10ml 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). The volume of brain injury visible on DWI and FLAIR within 48h 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.