MR assessment of fetal lung development using lung volumes and signal intensities

Abstract

The purpose of this study was to evaluate the monitoring and diagnostic potential of MRI in fetal lung development and disease using lung volume and signal intensity changes through gestation. Thirtyfive healthy fetuses (22-42 weeks) were examined on a 1.5-T MR system using sagittal T2w singleshot fast spin-echo imaging (TR indefinite, TE 90 ms, slice thickness/gap 3-5/0 mm, FOV 26-40 cm, NEX 0.5). Fetal body and lung were segmented manually and volumes calculated. Signal intensities (SI) of fetal lung and three reference values were measured on the section best displaying the lung. Regions of interests were defined by including the maximal organ area possible. The following SI ratios were generated: lung/liver, lung/amniotic fluid, lung/muscle, liver/fluid and liver/ muscle. Volumes and ratios were correlated with gestational age. Data from seven fetuses with pulmonary pathology were compared with these normative values. Absolute lung volume varied from 12.3 to 143.5 cm 3 in correlation with gestational age (P<0.001); lung volume relative to total body volume ranged from 1.6 to 5.0%, decreasing with gestational age (P=0.001). All SI ratios measured were unrelated to gestational age. Diagnoses in the seven abnormal fetuses were hydrothorax (n=2), congenital cystic adenomatoid malformation (n=2), diaphragmatic hernia (n=2) and pulmonary sequestration (n=1); their absolute and relative lung volumes were below normal (P<0.001). The SI ratios did not differ significantly from those in the normal population. Normative MR fetal lung volumes may have important clinical applications in confirming and quantifying intrauterine pulmonary hypoplasia and in complementing ultrasound in the planning of fetal and post-natal surgery. No clinical relevance was found for fetal lung SI values.

Prediction of postnatal outcomes in congenital diaphragmatic hernia using MRI signal intensity of the fetal lung

“…29 To standardize lung signal intensity, various organs such as spinal fluid, 11 liver 18,30 and muscle 31 have been used. We chosen the spinal fluid as the reference for the following reasons: (1) the spinal canal exists close to the lung, and in every transverse section of the lung; (2) the spinal fluid signal intensity is high, which reduces random error attributable to noise in the calculation of the final ratio; and (3) the spinal fluid signal intensity is not expected to change with increasing gestation time, 11 whereas liver intensity changes.…”

Radiographic findings of diaphragmatic hernia and hypoplastic lung

“…We can identify the characteristics of patients with CDH by prenatal diagnostic methods, and can estimate fetal-lung volume by threedimensional ultrasound, magnetic resonance images [8][9][10][11] or computed tomography and scintigram. 12 Nagaya et al 12 studied the lung function of 32 patients with CDH, in whom two parameters, lung volume by computed tomography and pulmonary perfusion amount by scintigram, were used.…”

Motion Corrected 3D Reconstruction of the Fetal Thorax from Prenatal MRI

“…Related Work: So far, fetal lung volumetry has been performed post mortem by weighing the inflated lungs in water and air [12] or in-vivo using either ultrasound [14] or manual segmentation of individual motion corrupted slices from MRI, taking only into account the thickness of the individual slices [9,8]. An overview over the variability of these methods is given in [4].…”