Neonatal subpial hemorrhage: clinical presentation, neuroimaging findings and outcome

Subpial hemorrhage is a rare form of intracranial hemorrhage (ICH) in neonates that remains underreported and inadequately understood. The aim of this study is to characterize the neuroimaging patterns of subpial hemorrhage, assess changes in the underlying brain parenchyma, and examine its clinical features and outcomes.

We reviewed the medical records and neuroimaging data of neonates with subpial hemorrhage admitted to our hospital between January 2010 and December 2023. Cases of subpial hemorrhages were identified through keywords searches within the hospital´s electronic database.

Twenty-eight patients were included in this retrospective study, 82% of whom were born at term. The most common clinical indication for imaging was a combination of apneas and seizures, ocurring in 50%. Hematologic abnormalities were present in 58% of patients. Magnetic resonance imaging (MRI) was performed acutely at the time of presentation between days 1 and 9 of life in 85% of cases. Subpial hemorrhages were unilateral in 86% of neonates, most commonly located in the temporal lobe (44%), and associated with other type of intracranial hemorrhage in 96% of cases, most often parenchymal (86%) and subdural (64%) hemorrhages. We identified three imaging patterns of subpial hemorrhage and two patterns of changes in the underlying brain parenchyma. Additionally, the hyperintense pia mater sign (HPm-sign) was observed on time-of-flight MR angiography (TOF-MRA) in 12 of 18 patients. Neurologic sequelae were noted in 28% of survivors.

Subpial hemorrhage has a distinctive MR pattern, often accompanied with cortical infarction and in most cases underlying parenchymal hemorrhage. In this study, we identified the HPm-sign that may be used to differentiate subpial hemorrhage from other types of hemorrhages. Additionally, we found a correlation between prominent medullary veins (PMV) and intraparenchymal hemorrhage (IPH).