Fetal Liver Volume and Morphology in Growth‐Restricted Fetuses and Their Association With Neonatal Morbidity: An MRI Study

BACKGROUND: Fetal growth restriction (FGR) may induce redistribution of the fetal circulation to preserve perfusion of vital organs. Reduced hepatic delivery of oxygen- and nutrient-rich blood may cause volumetric and morphological remodeling. PURPOSE: To quantify fetal liver volume and morphology in FGR and assess associations with adverse neonatal outcomes. STUDY TYPE: Single-center, prospective and retrospective. POPULATION: Ninety-two singleton pregnancies: 36 FGR cases (prospective) and 56 appropriate-for-gestational-age (AGA) controls (retrospective). FIELD STRENGTH/SEQUENCE: 3-T, True Fast Imaging with Steady-State Free Precession (TrueFISP) for fetal liver and body imaging, and TrueFISP or Half-Fourier Acquisition Single-shot Turbo Spin-Echo for brain imaging. ASSESSMENT: The fetal liver, body, and brain were segmented using deep learning tools. Liver volume, liver-to-body and brain-to-liver volume ratios, and 12 liver PyRadiomics shape features were assessed. Neonates were followed for composite adverse neonatal outcomes (CANO) until discharge. STATISTICAL TESTS: Linear regression assessed associations with gestational age in AGA fetuses. Linear mixed-effects models compared groups, adjusting for gestational age and fetal sex. Univariable logistic regression assessed associations with CANO. Benjamini-Hochberg correction controlled the false discovery rate at 0.05. RESULTS: ), lower liver-to-body ratio (0.053 ± 0.001 vs. 0.057 ± 0.001), and higher brain-to-liver ratio (2.637 ± 0.085 vs. 1.978 ± 0.047). FGR fetuses demonstrated significantly less elongated liver geometry, (10.7% higher PyRadiomics elongation values) and had a significantly higher surface-to-volume ratio (11.9%). CANO occurred in 30/92 neonates (27 FGR, 3 AGA). Higher brain-to-liver ratio (OR = 4.12, 95% CI: 1.93-8.77), PyRadiomics elongation values (less elongated geometry; OR = 2.04, 95% CI: 1.26-3.30), PyRadiomics flatness values (less flattened geometry; OR = 1.69, 95% CI: 1.07-2.65), and surface-to-volume ratio (OR = 3.26, 95% CI: 1.80-5.90) were significantly associated with CANO. DATA CONCLUSION: FGR was associated with reduced fetal liver size and altered geometry, which were associated with neonatal morbidity. EVIDENCE LEVEL: 2. TECHNICAL EFFICACY: 2.