Early MR features of hypoxic-ischemic brain injury in neonates with periventricular densities on sonograms

BACKGROUND AND PURPOSE: In the early 1980s, diagnosing periventricular leuk omalacia (PVL) in neonates by using cranial sonography was possible for the first time. Our purpose was to investigate the possibility of diagnosing P VL, in the acute stage by using MR imaging. We evaluated early MR features of hypoxic-ischemic brain injury in neonates with periventricular densities (flares) on cranial sonograms to determine the added value of MR imaging o ver sonography alone for early diagnosis of brain damage. METHODS: In a prospective study, infants who showed flares and/or cysts on sonograms underwent MR imaging during the (sub)acute stage. RESULTS: Fifty infants were classified according to the highest sonographic grade up to the day of MR imaging: 23 infants had sonographic grade 1 (fla res < 1 week), 15 had sonographic grade 2 (flares greater than or equal to 1 week), four had sonographic grade 3 (small localized cysts), and eight ha d sonographic grade 4 (extensive periventricular cysts); none had sonograph ic grade 5 (multicystic leukomalacia) on the day of MR imaging. Overall, th e additional information provided by MR imaging (over sonography alone) con sisted of the depiction of hemorrhagic lesions in 64% of the infants. Exten t and severity of the hemorrhages varied from isolated punctate lesions to extensive hemorrhages throughout the white matter; the latter were followed by cystic degeneration at autopsy in two infants, In nine of the 12 infant s with cystic PVL, MR images showed more numerous or more extensive cysts. In addition, in two infants, MR images showed cysts not present on sonogram s, In 32% of the infants, MR imaging provided no additional information; in these children, all but one had flares on sonograms whereas MR images show ed no abnormalities or a zone of mild periventricular signal change. CONCLUSION: MR imaging can depict the precise site and extent of hypoxic-is chemic brain injury at an earlier stage and allows a wider differentiation of lesions as compared with sonography alone. Hemorrhagic PVL is considered to be rare, but was present in 64% of our study population.