Three-dimensional sonographic features of fetal central nervous system anomaly

Objective. To visualize an intracranial structure of the fetal central nerv ous system (CNS) anomaly using transabdominal three-dimensional (3D) sonogr aphy. Methods. A total of 12 cases with fetal CNS anomalies (one unilateral ventr iculomegaly; three hydrocephalus; three anencephaly; three holoprosencephal y; one Dandy-Walker cyst; and one enlarged cisterna magna) from 17 to 37 we eks of gestation were studied with transabdominal 3D sonography (3.5 MHz), Results. In unilateral ventriculomegaly, insight view of dilated lateral ve ntricle, especially dilated atrium was depicted. In hydrocephalus, severely dilated bilateral ventricles and thin brain mantle were very clearly shown . In anencephalus, an absence of the brain and defect of the vault of the s kull was clearly noted. In holoprosencephaly, absent interhemispheric fissu re, common ventricle, and the extent of thalamic fusion were evident. In Da ndy-Walker cyst, cerebellar hemisphere was clearly depicted due to the agen esis of cerebellar vermis. In enlarged cisterna magna, posterior intracrani al view of the fetus showed a large space of cisterna magna. Although the d iagnosis of each CNS anomaly was made using conventional two-dimensional so nography, 3D sonography proved most helpful delineating the exact nature an d anatomic level of the anomaly. Conclusions These results suggest that 3D sonography provides a novel means of visualizing fetal CNS anomalies in utero. However, it should be noted t hat our 3D sonography cannot depict intracranial brain structures in normal fetuses or some CNS anomaly such as intracranial tumor.