Comparative Analysis of 2-D Versus 3-D Ultrasound Estimation of the Fetal Adrenal Gland Volume and Prediction of Preterm Birth
American Journal of Perinatology, 05/30/2012
Turan OM et al. – 2–D volume estimation of fetal adrenal gland using ellipsoid formula cannot replace 3–D AGV calculations for prediction of PTB.Methods
- Fetal AGV was estimated by three–dimensional (3–D) ultrasound (VOCAL) in 93 women with signs/symptoms of preterm labor and 73 controls.
- Fetal AGV was calculated using an ellipsoid formula derived from 2–D measurements of the same blocks (0.523 × length × width × depth).
- Comparisons were performed by intraclass correlation coefficient (ICC), coefficient of repeatability, and Bland–Altman method.
- The corrected AGV (cAGV; AGV/fetal weight) was calculated for both methods and compared for prediction of preterm birth (PTB) within 7 days.
- Among 168 volumes, there was a significant correlation between 3–D and 2–D methods (ICC = 0.979; 95% confidence interval [CI]: 0.971 to 0.984).
- The coefficient of repeatability for the 3–D was superior to the 2–D method (intraobserver 3–D: 30.8, 2–D:57.6; interobserver 3–D:12.2, 2–D: 15.6).
- Based on 2–D calculations, cAGV≥ 433 mm3/kg was best for prediction of PTB (sensitivity: 75%, 95% CI = 59 to 87; specificity: 89%, 95% CI = 82 to 94). Sensitivity and specificity for the 3–D cAGV (cutoff≥ 420 mm3/kg) was 85% (95% CI = 70 to 94) and 95% (95% CI = 90 to 98), respectively.
- In receiver–operating–curve curve analysis, 3–D cAGV was superior to 2–D cAGV for prediction of PTB (z = 1.99, p = 0.047).