A Novel Approach to Prenatal Measurement of the Fetal Frontal Lobe Using Three-Dimensional Sonography

To assess the feasibility of a standardized approach to biometric measurement of the fetal frontal lobe and to construct frontal lobe growth trajectories throughout gestation.

A sonographic 3-dimensional (3D) volume set was obtained and measured in 101 patients between 16.1 and 33.7 gestational weeks. Measurements were obtained by 2 independent raters. To model the relationship between gestational age and each frontal lobe measurement, flexible linear regression models were fit using penalized regression splines.

The sample contained an ethnically diverse population (7.9% Native Americans, 45.5% Hispanics/Latinas). There was high interrater reliability (correlation coefficients 0.95, 1.0, and 0.87 for frontal lobe length, width, and height; p values <0.001). Graphs of the growth trajectories and corresponding percentiles were estimated as a function of gestational age. The estimated rates of frontal lobe growth were 0.096 cm/week, 0.247 cm/week, and 0.111 cm/week for length, width, and height, respectively.

To our knowledge, this is the first study to examine fetal frontal lobe growth trajectories through 3D prenatal ultrasound examination. Such normative data will allow for future prenatal evaluation of a particular disease state by 3D ultrasound imaging.