Reference values for transverse cerebellar diameter throughout gestation.

The transverse cerebellar diameter (TCD) is well established in the ultrasound literature as a reliable parameter for estimating the duration of gestation. In cases of growth restriction the cerebellum is usually spared, making TCD a reliable indicator of gestational age even when other parameters fall off the appropriate growth curve. The purpose of this study is to establish normal values for the transverse diameter of the cerebellum in pathology specimens, and to determine if these values correlate with those obtained by ultrasound. We examined 96 specimens ranging from 14 to 42 weeks gestational age and found that our values correlate well with those published in the ultrasound literature. Mean TCD with 2 standard deviations for each gestational week were determined as reference values.