Periventricular Intraparenchymal Echodensities in the Premature Newborn: Critical Determinant of Neurologic Outcome

Abstract

Controversy exists concerning the degree of importance of periventricular intraparenchymal echodensities (IPE) observed on neonatal ultrasound scans in the determination of subsequent neurologic disability in premature infants. In this report, IPE was studied in 75 infants weighing less than 2,000 g at birth to determine the basic characteristics of the lesion, the likely pathogenesis, the outcome, and the aspects of the ultrasonographic appearance in the acute period of neonatal illness that are important for prediction of outcome. IPE was defined as any periventricular echodensity greater than 1 cm in at least one dimension. IPE was strikingly associated with large areas of intraventricular hemorrhage (IVH) (81% of cases). IPE was distinctly asymmetric. Thus, the lesion was either exclusively unilateral (67%) or bilateral with marked predominance on one side. The associated IVH was asymmetric in approximately 80% of cases, and in all 50 cases of large asymmetric IVH, IPE occurred on the same side as the larger amount of intraventricular blood. Moreover, more than 50% of such cases of IPE associated with large asymmetric IVH were progressive. Neuropathologic correlation showed that IPE represented hemorrhagic necrosis of periventricular tissue. Concerning pathogenesis, these data raise the possibility that large asymmetric IVH is related etiologically to IPE. Outcome varied with the severity of the IPE. Thus, the mortality rate among the 38 infants with extensive IPE was 79%. Of the survivors with extensive IPE, all had subsequent major motor deficits and all but one exhibited cognitive function less than 80% of normal. Among the 37 infants with localized IPE, the mortality rate was 38%. Of the survivors, although 79% had major motor deficits, 43% had cognitive function greater than 80% of normal. Thus, the findings demonstrate that with extensive IPE there is little or no chance for survival with normal neurologic and cognitive outcome, but with localized IPE, although major motor deficits are common, an appreciable proportion of infants have cognitive function in the normal range. Careful, quantitative assessment of the ultrasonographic features of IPE in the acute period of illness in the premature infant is of major value in estimating outcome.