Correlation of prenatal ultrasound diagnosis and pathologic findings in fetal brain abnormalities

To determine the degree of agreement between prenatal ultrasound diagnosis of brain abnormalities and subsequent pathologic findings.

Between August 1993 and August 1999 there were 62 cases where a fetus with a prenatal ultrasound diagnosis of a brain abnormality other than neural tube defects underwent autopsy at the Regional Department of Pediatric Pathology. The cerebral diagnosis at ultrasound was compared with the findings at autopsy in all cases.

In 47 of 61 (77%) cases the same defects were seen on ultrasound and at autopsy. The most common disparity was with the Dandy-Walker malformation or variant, where only six of the 14 (43%) cases prenatally diagnosed with this condition showed the same abnormality at autopsy. When fetuses with the Dandy-Walker malformation or variant were excluded, the scan findings correlated with autopsy in 41 of 47 (87%). In the main group with discordant findings, five of the seven cases where termination of pregnancy was undertaken had other fetal anomalies on ultrasound examination which were confirmed at autopsy. In the sixth case there was autolysis of brain tissue which affected detailed autopsy.

A very high level of agreement between prenatal ultrasound and autopsy findings was found for all abnormalities of the fetal brain, except for the Dandy-Walker malformation or variant. Potential discrepancy in findings between ultrasound and autopsy should be explained to patients who are considering termination of pregnancy for the Dandy-Walker type of abnormality.