Objective: The choroid plexus typically fills the atrium of the lateral ventricles of the brain in normal fetuses, but separates from the medial ventricular wall with increasing ventriculomegaly. Sonographic depiction of choroid plexus-ventricular wall separation has been associated with a high frequency of unfavorable outcomes in fetuses with mild ventricular dilatation. This separation, however, is also observed in a small subgroup of fetuses with normal ventricular measurements. The objective of this study was to ascertain the prognosis for fetuses when choroid plexus-ventricular wall separation and normal-sized lateral ventricles are seen on antenatal sonograms.
Materials and methods: Postnatal follow-up was reviewed for 74 fetuses showing a 3 mm or greater separation between the choroid plexus and the medial ventricular wall and normal-sized (< or = 10 mm) ventricles on antenatal sonograms. Fetuses were divided into normal and abnormal outcome groups, and the data were analyzed to determine if the amount of separation, the ventricular atrial diameter, or the evolution of these findings on follow-up sonograms was predictive of outcome.
Results: Fifty-nine patients (80%) had normal outcomes (defined as no congenital anomalies and no significant subsequent medical history apart from usual infant and childhood illnesses) and 15 patients (20%) had abnormal outcomes. The severity of the abnormalities varied widely, ranging from relatively inconsequential, such as isolated polydactyly, to complex congenital malformation syndromes resulting in neonatal death. No consistent pattern of malformation was evident. Although we found a statistically significant difference in the degree of choroid plexus-ventricular wall separation when fetuses were separated into normal and abnormal outcome groups, the range of measurements obtained in these two populations overlapped considerably. Outcomes were normal in all 13 patients in whom the choroid plexus-ventricular wall separation had returned to normal by the time of the last antenatal sonogram.
Conclusion: A separation of 3 mm or greater between the choroid plexus and the medial ventricular wall is an important finding that is associated with an increased risk of an abnormal outcome even in the subpopulation of fetuses with normal-sized ventricles. Although the outcome will be normal in the majority (80%) of such fetuses, identification of choroid plexus-ventricular wall separation mandates a meticulous examination of fetal anatomy.