A nomogram of fetal lung volumes estimated by 3-dimensional ultrasonography using the rotational technique (Virtual organ computer-aided analysis)

Objective. The purpose of this study was to build a nomogram of normal fetal lung volumes throughout gestational age estimated by 3-dimensional ultrasonography using the rotational technique (Virtual Organ Computer-Aided Analysis [VOCAL] GE Healthcare, Kretztechnik, Zipf, Austria). Methods. Fetal lung volume was assessed in 146 healthy fetuses by 3-dimensional ultrasonography using the technique of rotation of the multiplanar imaging (VOCAL). Inclusion criteria were healthy women with singleton normal pregnancies, normal fetal morphologic ultrasonographic findings, reliable dating established by dates and by ultrasonographic measurement of the crown-lump length in the first trimester, and gestational age from 20 to 37 weeks. Exclusion criteria were discordance between clinical and ultrasonographic dating, patients lost to follow-up, and birth weight disorders. Each patient was scanned once during pregnancy. Results. The right, left, and total mean pulmonary volumes ranged, respectively, from 5.37, 4.66, and 9.95 cm³ at 20 weeks to 46.06, 37.34, and 84.35 cm3 at 37 weeks. The logistic transformation analysis yielded the following formulas: right lung volume = exp(4.07/[1 + exp(21.90 - gestational age/5.44)]) left lung volume = exp(3.82/(1 + exp[22.03 - gestational age/5.17)]) and, total lung volume = exp(4.72/[1 + exp(20.30 - gestational age/6.05)]). Conclusions. A new nomogram of fetal lung (right, left, and total) volumes throughout gestational age using the rotational technique (VOCAL) is described, and reference values have been generated.