Frequency of ulegyria on delayed MRI scans in children with term hypoxic-ischemic injury

Ulegyria is an under-recognized and underreported potential sequela of hypoxic-ischemic injury (HII) in full-term neonates. Ulegyria is a unique form of parenchymal scarring that leads to a mushroom-shape of the affected gyri resulting from volume loss at the deep portions of the sulci during HII in this specific period in infantile neurodevelopment. Identifying ulegyria is important for ascribing cause and timing of HII on delayed magnetic resonance imaging (MRI) scans and because of its close association with pharmaco-resistant epilepsy.

The purpose of this study was to determine the frequency of ulegyria and characterize the anatomical distribution of watershed injury in a large database of patients who developed cerebral palsy with term HII pattern and underwent delayed MRI.

Patients with term HII patterns on MRI were analyzed for ulegyria. The frequency of ulegyria overall and for each pattern of HII distribution was determined as was the anatomical distribution of watershed injury.

Of the 731 children with term HII and cortical injury, 484 (66%) had ulegyria. Ulegyria was most common in those cases with a combined watershed/basal ganglia-thalamic pattern (56%) and isolated watershed pattern (40%). Watershed injury in patients with ulegyria was most common at the posterior watershed (80.6%) and perisylvian watershed (76.7%).

Ulegyria was present in nearly two-thirds of patients with term HII and cortical injury and should be sought to support the diagnosis of previous perinatal HII, especially in posterior and perisylvian watershed regions. The implications of ulegyria can be significant for clinical decision-making and for ascribing timing of injury to the perinatal period.