Abstract Objective:Evaluate deformable slice-to-volume registration
(DSVR) to calculate 3D-segmented total lung volume (TLV) in fetuses with
congenital diaphragmatic hernia, congenital lung lesions and healthy
controls, with comparison to 2D-manual segmentation. Design:Pilot study
Setting:Regional fetal medicine referral centre Sample:Fetal MRIs
performed for clinical indications (abnormal cases) or as research
participants (healthy controls) Methods:Sixteen MRI datasets of fetuses
(22-32 weeks GA). Diagnosis: CDH(n=5), CPAM(n=2), CDH with BPS(n=1) and
healthy control(n=8). DSVR was used for reconstruction of 3D isotropic
(0.85 mm) volumes of fetal body followed by semi-automated lung
segmentation. The resulting 3D TLV were compared to the traditional
2D-based volumetry, and a normogram of DSVR-derived fetal lung volumes
from 100 cases was produced. Main Outcome Measures:Concordance with
2D-volumetry assessed with Bland-Altman analysis, results of
segmentations presented visually. Observed/Expected values were
calculated for abnormal cases based upon the normogram.
Results:DSVR-derived TLV values have high correlation with the 2D-based
measurements but with a consistently lower volume; bias -1.44cm3 [95%
limits: -2.6 to -0.3] with improved resolution able to exclude hilar
structures even in severe motion corruption or in cases of lung
hypoplasia. Conclusions:Application of DSVR for fetal MRI provides a
solution for analysis of motion corrupted scans and does not suffer from
the interpolation error inherent in 2D-segmentation as per current
clinical practice. It increases information content of acquired data in
terms of visualising organs in 3D space and quantification of volumes,
which we believe will have important value for counselling and surgical
planning. Keywords:Fetal MRI; congenital diaphragmatic hernia; CPAM;
lung volume
P255: Fetal lung volume assessment by three-dimensional ultrasound in isolated congenital diaphragmatic hernia as a prognostic factor