Human fetal lung morphometry at autopsy with new modeling to quantitate structural maturity.
To demonstrate a simplified morphometric procedure, including a new model for acinar structural maturity, applicable to autopsy fetal lung and present reference values for these parameters.



Cases with autopsy consent for research were studied. To simplify analysis only critical morphometric parameters were measured to allow calculation of gas-exchange surface area.



A total of 58 fetuses, 16-40 weeks were included. Subjects were rejected with any condition predisposing to pulmonary hypo/hyperplasia, significant maceration, or if lung weight/bodyweight or microscopy identified pulmonary hypoplasia or lung growth disorders.



Lungs were inflation fixed, weights and volumes determined, sampled, then returned to the body. Volume densities (VV) of parenchyma/non-parenchyma and air-space/gas-exchange tissue, gas-exchange surface density (SV), and total surface area (SA) were determined. The number, mean radius, and septal thickness of modeled airspace-spheres were calculated. Equations were generated for each parameter function of gestation and bodyweight.



From 16 to 40-week weights and volumes increased as power functions from ∼4 g/mL to ∼90 g/mL. Parenchyma/non-parenchyma changed little-75:25 (16 weeks) to 71:29 (term). Parenchyma was 10% airspace:90% tissue early and 50:50 by term. Gas-exchange SVincreased from 175 to 450 cm2/cm3and total SA increased from 0.059 to 4.793 m2. There were 3.31 × 106airspace-spheres, 12 µ radius, septal thickness 30 µ at 16 weeks, increasing to 56.92 × 106, 26 µ radius, septal thickness 13 µ by term.



Morphometry can feasibly be performed at autopsy, providing more informative quantitative data on lung structural development than current methods utilized. This reference data set compares well with published data.
Department of Anatomical Pathology, S.A. Pathology, Women's and Children's Hospital, Adelaide, South Australia.|Department of Obstetrics and Gynaecology, University of Adelaide, Adelaide, South Australia.
Jill
J
Lipsett
D001344:Autopsy; D005333:Fetus / Q000033:anatomy & histology*; D006801:Humans; D008168:Lung / Q000033:anatomy & histology*
pulmonary development morphometry