Early diffusion restriction of white matter in infants with small subdural hematomas is associated with delayed atrophy.

Abstract

Traumatic brain injury (TBI) is a major cause of infant morbidity and mortality. In these patients, magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI) is the test of choice to describe the extent of microstructural injury. In this case series, we describe novel acute and chronic MRI findings in four infants (6-19months) with small, unilateral subdural hematomas in whom the etiology of head injury was suspicious for non-accidental trauma (NAT). Acute (<1-week post-injury) DWI revealed extensive areas of restricted diffusion isolated to the cerebral white matter predominantly ipsilateral to the subdural hematoma. After prolonged pediatric intensive care treatment including subdural evacuation (n=2) or decompressive craniectomy (n=1), all patients survived albeit with significant motor and cognitive deficits. Delayed structural MRI (6-9-year post-injury) demonstrated cortical and subcortical atrophy well-correlated with areas of acute restricted diffusion. These four cases highlight that relatively small subdural hematomas can be associated with extensive white matter injury-detectable only by early DWI-which have long-term structural and functional consequences.