Postischemic hypervascularity of infancy: a stage in the evolution of ischemic brain damage with characteristic CT scan.

One to 2 weeks after severe brain ischemia, four infants developed an unusual vascular lesion with a characteristic appearance on computed tomography that has not been reported previously. Restricted areas (most frequently the basal ganglia and thalamus) displayed increased attenuation, which enhanced further upon infusion of contrast medium. Autopsy of one infant revealed that the CT abnormality corresponded to an extremely dense neovascular network which had almost completely replaced the parenchyma in that region. We postulate that this pathological change is a stage in the organization of ischemic brain damage reflecting the infant's vascular plasticity. Thus, hypoxia induces marked capillary proliferation in regions of normally high metabolism and capillary density. The CT pattern may prove useful in predicting the location and extent of sequelae to perinatal asphyxia.