Imaging Patterns of Neonatal Subpial Hemorrhage – Provisional Statements on Neurological Outcomes

BACKGROUND AND PURPOSE: 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. The study aims to evaluate the association between imaging findings and neurological outcomes at follow-up in neonates with subpial hemorrhage.

MATERIALS AND METHODS: 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 for medullary vein engorgement/thrombosis. We extracted demographic data, perinatal events, hospital outcomes, and Alberta Infant Motor Scale (AIMS) scores, when available. Descriptive analysis was used for demographic, clinical, and imaging findings. Fisher's exact test evaluated associations between clinical outcomes and imaging findings.

RESULTS: Twenty-nine patients (median gestational age 38 weeks, IQR: 37-39) were included, with 82% having birthweights >2500g. 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 AIMS (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 neurological deficit (p=.055).

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

ABBREVIATIONS: AIMS= Alberta Infant Motor Scale; IQR= Interquartile Ranges; NICU= Neonatal Intensive Care Unit; SD= Standard Deviations.