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Reference ranges for 2-dimensional sonographic lung measurements in healthy fetuses: a longitudinal study
Ingrid Schwach Werneck Britto1, Edward Araujo Júnior1, Haleh Sangi-Haghpeykar1
1Department of Obstetrics and Gynecology, Medical Science College of Santa Casa of São Paulo, São Paulo, Brazil (I.S.W.B., L.C.S.B.); Department of Obstetrics, Federal University of São Paulo, São Paulo, Brazil (E.A.J.); and Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Baylor College of Medicine and Texas Children's Hospital Fetal Center, Houston, Texas USA (H.S.-H., R.L.D., M.A.B., W.L., R.R.).
Objectives:
The purpose of this study was to establish reference ranges for 2-dimensional sonographic measurements of fetal lungs from longitudinal data.
Methods:
A total of 214 fetal lung measurements were longitudinally evaluated in 62 healthy fetuses between 20 and 36 weeks' menstrual age. Both right and left lung areas were measured in the heart 4-chamber view using lung area tracing and axis diameter methods. Multilevel modeling was used to evaluate the expected values and variability with respect to menstrual age and to generate reference ranges for the lung area, lung-to-head ratio, quantitative lung index, and observed-to-expected lung-to-head ratio for both lungs.
Results:
The expected values varied with menstrual age for all parameters. Variance was menstrual age dependent for all parameters except the longest diameter area measurements and their lung-to-head ratios.
Conclusions:
Models are presented for expected 2-dimensional sonographic lung size parameters and their variance as a function of menstrual age. These data have been used to generate age-specific reference ranges for both measurements and indices.
