Imaging Patterns of Neonatal Subpial Hemorrhage: Provisional Statements on Neurologic Outcomes

Subpial hemorrhage is an underrecognized type of hemorrhagic stroke primarily affecting neonates. Blood accumulation in the impermeable pia mater compresses the adjacent cortex, leading to injury. The consequences of this stroke type remain poorly understood. This study aims to evaluate the association between imaging findings and neurologic outcomes at follow-up in neonates with subpial hemorrhage.

We retrospectively included neonates with suspected subpial hemorrhage who underwent brain MRI between January 2012 and February 2024. Two pediatric neuroradiologists evaluated MRIs for subpial hemorrhage location, size, and pattern using a previously described system that classified subpial hemorrhage only (pattern A), subpial hemorrhage with cortical injury (pattern B), and subpial hemorrhage with cortical injury and intraparenchymal hemorrhage (pattern C). They also assessed medullary vein engorgement/thrombosis. We extracted demographic data, perinatal events, hospital outcomes, and Alberta Infant Motor Scale scores, when available. Descriptive analysis was used for demographic, clinical, and imaging findings. The Fisher exact test evaluated associations between clinical outcomes and imaging findings.

Twenty-nine patients (median gestational age, 38 weeks; interquartile range, 37-39 weeks) were included, with 82% having birth weights of >2500 g. Subpial hemorrhages were most commonly on the right side (66%) and in the temporal lobe (62%). Most hemorrhages measured 1-4 cm (59%). Pattern C (15/29, 52%) was associated with delayed motor development as assessed by Alberta Infant Motor Scale (9/15, 60%) (P = .042), while pattern B (10/29, 35%) was associated with near-normal motor development (6/15, 40%) (P = .044). There was no statistically significant association between concurrent superficial and deep medullary vein engorgement/thrombosis and the presence of any neurologic deficit (P = .055).

The association between subpial hemorrhage patterns and neurologic outcomes, particularly motor development, may have important prognostic and management implications. In our cohort, pattern C of subpial hemorrhage showed a statistically significant association with delayed motor development. Concurrent involvement of superficial and deep medullary vessels may indicate a higher risk of poor neurologic outcomes. These findings highlight the importance of early intervention and monitoring in neonates presenting with subpial hemorrhage.