Neonatal transverse cerebellar diameter in normal and growth-restricted infants

OBJECTIVE: To assess the transverse cerebellar diameter (TCD) in preterm and term neonates with normal growth or growth restriction. METHODS: TCD was sonographically measured after birth in 404 neonates born between 23 and 42 weeks of gestation. The study included two groups: Group 1: 334 appropriately grown for gestational age (AGA) neonates (both birthweight (BW) and head circumference (HC) were between the 3rd and 97th centiles), which were subdivided into two subgroups according to the HC measurements. Group 2: 70 small for gestational age (SGA) neonates (BW <3rd centile), were further divided into three subgroups according to HC measurements. RESULTS: In Group 1 of AGA neonates, a linear growth function was observed between the TCD and GA (R = 0.914, P < 0.00001, TCD = 0.279 + 0.142 X GA), and between TCD and HC (R = 0.886, P < 0.00001, TCD = -0.333 + 1.777 X HC). The percentage of neonates with normal TCD (> or =10th centile) was more than 85% of the AGA and asymmetric SGA subgroups, and 60.7% of the microcephalic SGA subgroup (P < 0.02). CONCLUSIONS: This study provides normative data of neonatal TCD across gestational age. TCD measurement via sonography is a new adjunctive criterion for objectively assessing gestational age in infants when a precise determination of gestational age is necessary. This is very important since utility of the TCD is effective for both AGA and asymmetric SGA infants.