Skeletal and total body volumes of human fetuses: assessment of reference data by spiral CT

OBJECTIVE: To define reference data for skeletal and total body volumes of normal human fetuses. MATERIALS AND METHODS: Spiral CT was used to assess the skeletal and total body volumes of 31 normal human stillborn infants with gestational age (GA) and body weight (BW) ranging from 14 to 41.5 weeks and 22 to 3,760 g, respectively. CT scans (slice thickness 2.7 mm, pitch 0.7) were performed within the first 24 h after delivery. Precise bone and soft-tissue windows were defined from analysis of the density along the diaphysis of the fetal long bones and from the measurement of a phantom that mimics soft tissues. Lengths and volumes were obtained from 3D reconstructions. The femur lengths measured from CT images (FLct) were compared with those provided by US studies (FLus). RESULTS: Significant correlations ( r>0.9) were found between BW, measured volumes of the entire skeleton or head, long-bone lengths, biparietal diameter and GA. Strong linear correlations ( r>0.98) were observed between FLct and FLus. CONCLUSIONS: Skeletal and total body volume values obtained using spiral CT were significantly correlated with fetal biometric measurements. These data could complement those obtained in obstetric investigations with US.