Sonographic Measurement of the Fetal Cerebellar Vermis

ABSTRACT

PURPOSE: To obtain a reference value for fetal vermian size measured with sonography. MATERIALS AND METHODS: A prospective study of normal singleton pregnancies was performed. The fetal vermian width and anterior-posterior (AP) diameter were measured with axial image by transabdominal sonography between 18 and 37 weeks of gestation in 264 singleton fetuses. Linear regressions of the vermian width and AP diameter as a function of gestational age (GA), biparietal diameter (BPD), head circumference (HC) and transcerebellar diameter (TCD) were calculated. RESULTS: Adequate vermis measurements were obtained in 264 fetuses. Vermian width was correlated well with GA (r2 = 0.851), BPD (r2 = 0.824), HC (r2 = 0.844) and TCD (r2 = 0.859). AP diameter was also correlated with GA (r2 = 0.826), BPD (r2 = 0.843), HC (r2 = 0.814) and TCD (r2 = 0.836). All the correlation coefficients were highly statistically significant (p < 0.001). Nomograms of the vermian width and AP diameter according to the gestational age were obtained. CONCLUSION: Measured fetal vermian size was correlated well with GA which confirmed the usefulness of the rermian size as a reference value for the assessment of vermian development.