Background:The aim of the study was to analyze the development of the lateral ventricles during the 1[sup]st[/sup]sand 2 [sup]nd[/sup] trimester of fetal life using computerized image processing, and to compare the findings with the results obtained by ultrasound imaging and MRI.Material/Methods:The material consisted of 32 fetuses from spontaneous abortions,54 .235 mm crown-rump length. After detached craniotomy, the brains were cut into axial sections; the sections were filmed with a video camera and then analyzed using specialized software packages.Results:In 12 analyzed brains, no significant pathological changes were observed in the cerebral emispheres, whereas the remaining 20 (63%)demonstrated visible pathology. In 10 cases there were areas of leukomalacia, in 5 intra-and periventricular hemorrhages, and in 2 fetuses ventriculomegaly with lateral ventricular triangles over 10 mm wide (in cases of active hydrocephalus and colpocephaly).In 1 case of an 18-week-old fetus, lateral ventricular morphology typical of hydrocephalus (generalized distension)was observed with ventricular triangles 8.5 mm wide. The other 2 fetuses demonstrated developmental defects. The frontal horns were the most markedly enlarged in both cases of hydrocephalus (100%)and were semicircular, whereas after intra-and periventricular hemorrhages they were less enlarged and triangular, with the base of the triangle directed to the front and frequent significant asymmetry. Conclusions: The shape of the ventricular system, including that of the frontal horns, is important in the diagnostics of fetal CNS.

Keywords: Abortion, Spontaneous, Cerebral Ventricles - anatomy & histology, Cerebral Ventricles - growth & development, Cerebral Ventricles - pathology, Cerebral Ventricles - ultrasonography, Fetus - anatomy & histology, Pregnancy, Pregnancy Trimester, First, Pregnancy Trimester, Second, Prenatal Diagnosis