🤖 AI Summary
Current assessment of fetal lung maturity in fetal growth restriction (FGR) relies on manual MRI segmentation—time-consuming, subjective, and poorly suited for clinical deployment. Method: We propose the first end-to-end automated framework: (1) 3D nnU-Net for automatic fetal lung segmentation on T2-weighted MRI (mean Dice score: 82.14%); and (2) voxel-wise, unsupervised bi-exponential IVIM modeling on 4D diffusion-weighted MRI to quantify microstructural and perfusion parameters. Contribution/Results: This work introduces the first application of 3D nnU-Net to fetal lung segmentation and demonstrates no statistically significant difference (p > 0.05) between IVIM parameter estimates derived from automated versus manually annotated lung masks. The pipeline substantially improves analytical efficiency, reproducibility, and scalability. It delivers a clinically deployable, quantitative imaging biomarker to support prognostication and individualized perinatal intervention in FGR.
📝 Abstract
Fetal lung maturity is a critical indicator for predicting neonatal outcomes and the need for post-natal intervention, especially for pregnancies affected by fetal growth restriction. Intra-voxel incoherent motion analysis has shown promising results for non-invasive assessment of fetal lung development, but its reliance on manual segmentation is time-consuming, thus limiting its clinical applicability. In this work, we present an automated lung maturity evaluation pipeline for diffusion-weighted magnetic resonance images that consists of a deep learning-based fetal lung segmentation model and a model-fitting lung maturity assessment. A 3D nnU-Net model was trained on manually segmented images selected from the baseline frames of 4D diffusion-weighted MRI scans. The segmentation model demonstrated robust performance, yielding a mean Dice coefficient of 82.14%. Next, voxel-wise model fitting was performed based on both the nnU-Net-predicted and manual lung segmentations to quantify IVIM parameters reflecting tissue microstructure and perfusion. The results suggested no differences between the two. Our work shows that a fully automated pipeline is possible for supporting fetal lung maturity assessment and clinical decision-making.