Purpose or Case Report: To compare lung signal intensity between normal fetuses and those with left-sided congenital diaphragmatic hernia (CDH) with liver herniation, evaluating the contralateral (right) lung on T2-weighted MRI.
Methods & Materials: This retrospective study included fetal MRIs acquired on a 1.5 T scanner using T2 HASTE/SSFSE sequences. The control group comprised healthy fetuses divided into three gestational age ranges: Group 1 (20–23 weeks, n = 12), Group 2 (24–27 weeks, n = 10), and Group 3 (28–31 weeks, n = 10). The CDH group included 10 fetuses with left-sided CDH and intrathoracic liver herniation (3 in Group 1, 3 in Group 2, and 4 in Group 3). Signal intensity (SI) was measured in triplicate using circular regions of interest with a fixed area of 1.5 mm2 placed in the right (contralateral) lung—above, at, and below the hilum—avoiding vessels and motion artifacts. The mean SI per fetus was calculated. Normality was assessed using the Shapiro–Wilk test, and comparisons were performed using the Kruskal–Wallis test with Dunn’s post-hoc correction and Student’s t-test when applicable. Institutional review board approval was obtained.
Results: Normal fetuses showed a progressive increase in pulmonary SI with gestational age (p < 0.01), consistent with physiologic lung maturation. Mean right lung SI values were 287.3 ± 33.9, 314.7 ± 70.9, and 373.4 ± 75.7 for Groups 1, 2, and 3, respectively. Fetuses with left-sided CDH showed lower contralateral lung SI in all groups, with a significant difference at 28–31 weeks (CDH: 211.2 ± 58.6 vs. Controls: 373.4 ± 75.7; p = 0.006). The correlation between gestational age and SI was weaker in CDH (r = 0.41) compared with controls (r = 0.78), suggesting delayed pulmonary maturation even in the contralateral lung.
Conclusions: Quantitative analysis of contralateral lung T2 signal intensity reveals a significant reduction in fetuses with left-sided CDH and liver herniation, indicating global impairment of lung development. These findings suggest that pulmonary hypoplasia in CDH extends beyond the ipsilateral side and affects overall lung maturation. Quantitative T2 signal assessment therefore emerges as a reproducible and clinically meaningful imaging biomarker for evaluating the severity of pulmonary hypoplasia in affected fetuses.