Parenchymal brain injury in the preterm infant: comparison of cranial ultrasound, MRI and neurodevelopmental outcome.

Aim: Magnetic resonance imaging (MRI) is increasingly being used in high-risk preterm neonates. Cranial ultrasound (US) was compared with MRI in preterm patients with parenchymal injury and related to neurodevelopmental outcome.
Patients and Methods: Studies were performed in 61 patients. Twelve infants with normal US (Group 1) had an MRI within the first 4 weeks of life (early MRI), and 10 also at term age (late MRI). Eight out of 20 infants with intraventricular haemorrhage with parenchymal involvement (IVH + PI) (Group 2) had an early as well as a late MRI and 12 a late MRI. Of the 20 patients with cystic-periventricular leukomalacia (c-PVL) (Group 3), 7 had an early MRI, 1 had an MRI on both occasions and 12 had a late MRI. All 9 children with focal infarction (FI) (Group 4) had a late MRI.
Results: MRI was conform with cranial US in Group 1. Early MRI in Group 2 showed contralateral c-PVL in one infant and an additional contralateral occipital parenchymal haemorrhage and blood in the posterior fossa in another infant. Late MRI showed an asymmetrical posterior limb of the internal capsule (PLIC) (n=6), which predicted later hemiplegia. Early MRI in Group 3 showed more cysts (n = 5), punctate white matter lesions (n = 6), lesions in the basal ganglia (n = 1) and once involvement of the cerebellum. Late MRI showed involvement of the centrum semiovale (n = 2) lesions in the basal ganglia (n = 2) and bilateral abnormal signal intensity of the PLIC in 7 infants who all went on to develop cerebral palsy. In Group 4 MRI showed signal intensity changes suggestive of cystic lesions compared to persisting echogenicity on US (n = 3) and an asymmetrical PLIC (n = 5), which predicted hemiplegia in 4.
Conclusion: Early MRI especially provided additional information in those with c-PVL. MRI at term age could assess the PLIC, which was useful in children with unilateral parenchymal involvement, for prediction of subsequent hemiplegia and, to a lesser degree, in bilateral c-PVL for prediction of diplegia or quadriplegia.