Abnormalities of the neonatal brain: MR imaging. Part I. Intracranial hemorrhage.

The authors prospectively evaluated 82 neonates, ranging in gestational age from 29 to 44 weeks postconception, with magnetic resonance (MR) imaging at 0.6 T. Twenty-two cases of hemorrhage in 15 infants were identified. Ultrasound (US) and computed tomography (CT) were superior to MR in the first few days after parenchymal hemorrhage, since at this time lesions were apparent on only T2-weighted images. After the first 3 days, MR was the single best modality because (a) hemorrhage on CT became imperceptible in the 2d week, whereas the high signal of hemorrhage on MR persisted for 2-11 weeks; (b) MR permitted rough dating of hemorrhage according to changes in signal intensity; and (c) MR was superior in identifying subdural or epidural hemorrhage. Because of the nonspecificity and restricted field of view of US and the inability of CT to depict hemorrhage after 7-10 days, the authors conclude that MR significantly improves the detection of intracranial hemorrhage in neonates.