Cavum velum interpositum cysts in normal and anomalous fetuses in second trimester of pregnancy: Comparison of its size and prevalence.

ABSTRACT

OBJECTIVE: Cavum veli interpositi (CVI) is a potential space below the splenium of corpus callosum and sometimes presents as a cyst. MATERIALS AND METHODS: In this prospective cross-sectional study, 360 fetuses with normal second trimester scan and 152 s trimester fetuses with structural abnormalities were included. RESULTS: The CVI cysts were more common in fetuses with brain anomaly compared to normal fetuses and fetuses with extra-central nervous system (CNS) anomalies (23% vs 18.3% and 18% respectively; p value < 0.01). The mean size of cysts in normal fetuses, fetuses with extra-CNS anomalies and fetuses with brain abnormalities was 4.6 mm, 5.8 mm and 9.2 mm respectively. There was a significant difference between cysts size in normal fetuses and fetuses with brain anomalies (p value < 0.01) and the cut-point was 7.1 mm. CONCLUSION: The prevalence of CVI cysts is more in fetuses with brain anomaly. Fetuses with a cyst size >7.1 mm need a more detailed brain examination.