Distinguishing multicystic from focal encephalomalacia on delayed MRI in children with term hypoxic ischemic injury

Background and Purpose

To define cystic patterns resulting from term hypoxic ischemic injury (HII) on delayed Magnetic Resonance Imaging (MRI) and determine associated HII patterns and lesions that reflect the severity of injury, from a database of African children with cerebral palsy.

Methods

Retrospective review of 1175 children with cerebral palsy due to term HII diagnosed on late MRI, identifying those with cystic changes. These were classified as multicystic or (multi-) focal-cystic, and were evaluated for associated injuries—thalami, basal ganglia, hippocampi, cerebellum, and presence of ulegyria.

Results

Three hundred and eighty-eight of 1175 (33%) children had cystic encephalomalacia. Two hundred and seven of 388 (53.3%) had focal-cystic and 181/388 (46.6%) had multicystic injury. The focal-cystic group comprised 87.9% (182/207) with thalamic injury, 25.6% (53/207) with basal ganglia injury, and 15% (31/207) with cerebellar involvement. Basal-ganglia-thalamus (BGT) pattern was present in 43.9% (91/207) and ulegyria in 69.6% (144/207). In the multicystic group, 88.9% (161/181) had thalamic injury, 30.9% (56/181) had basal ganglia injury, and 21% (38/181) had cerebellar involvement. BGT pattern was observed in 29.8% (54/181) and ulegyria in 28.7%. (52/181). Significant associations (p<.05) were found between multicystic injury and caudate/globus pallidus involvement, and between focal-cystic pattern of injury and ulegyria.

Conclusions

Cystic encephalomalacia was seen in almost one-third of patients with term HII imaged with delayed MRI, with a similar prevalence of focal-cystic and multicystic injury. Multicystic injury was associated with caudate and globus pallidi involvement, typical of the BGT pattern of HII, whereas the focal-cystic pattern was associated with ulegyria, typical of watershed injury.