Diagnostic accuracy of prenatal ultrasound and MRI in predicting survival in severe isolated congenital diaphragmatic Hernia: A systematic review and meta-analysis.

OBJECTIVE

To investigate the predictive accuracy of the ultrasound-measured observed/expected (O/E) lung-to-head ratio (LHR) versus MRI-measured O/E total fetal lung volume (TFLV) in predicting postnatal survival in fetuses with an isolated congenital diaphragmatic hernia (CDH) undergoing expectant management.

METHODS

A systematic review was conducted including studies reporting on the prognostic value of ultrasound-measured O/E LHR and MRI-measured O/E TFLV in predicting survival to hospital discharge in fetuses diagnosed with isolated CDH. Pregnancies undergoing fetal therapy were excluded. The overall accuracy was assessed by computing summary estimates of sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR-), and diagnostic odds ratio (DOR), using the hierarchical summary receiver operating characteristics (HSROC) model. Synthetic analysis included studies in which the number of true-positive, false-positive, false-negative, and true-negative cases was available or deducible. We planned a subgroup analysis based on index test cut-offs and the side of CDH (left or right). Heterogeneity was assessed using Cochran's Q statistic.

RESULTS

This systematic review included 33 studies comprising 1702 fetuses with isolated CDH published between 2000 and 2024. The meta-analysis included 18 studies encompassing 960 fetuses with ultrasound-measured O/E LHR and 742 fetuses with MRI-measured O/E TFLV. In the ultrasound studies, the pooled survival was 62 % compared to 68 % in the MRI studies. Both O/E LHR and O/E TFLV were significantly associated with survival (pooled O/E LHR 0.07, 95 % CI 0.04, 0.13; pooled O/E TFLV 0.09, 95 % CI 0.05, 0.17). In all severe CDH cases, both US and MRI appeared comparable. The O/E LHR had a pooled sensitivity of 72.2 % (95 % CI 64.9-78.4), specificity of 83.9 % (95 % CI 71.2-91.6), DOR of 13.5 (95 % CI 7.2-25.3), LR+ of 4.48 (95 % CI 2.5-8.0), and LR-of 0.33 (95 % CI 0.3-0.4). The O/E TFLV had a pooled sensitivity of 84 % (95 % CI 74.7 90.3), specificity of 62.5 % (95 % CI 45.5-76.8), DOR of 8.72 (95 % CI 3.4-22.4), +LR of 2.24 (95 % CI 1.4-3.5), and -LR of 0.26 (95 % CI 0.1-0.5). In the subgroup analysis of left-sided CDH, although the pooled sensitivity and DOR appeared higher using MRI, the 95 % CI overlapped: O/E LHR had a sensitivity of 73.6 (95 % CI 61.5-82.9), specificity 82.0 (95 % CI 63.8-92.2), DOR 12.7 (95 % CI 5.9-27.1), + LR 4.09 (95 % CI 2.0-8.2), and -LR 0.32 (95 % CI 0.2-0.5), while the O/E TFLV had sensitivity of 91.2 (95 % CI 79.7-96.5), specificity of 78.1 (95 % CI 65.3-87.1), DOR 37.1 (95 % CI 12.3-111.6), +LR 4.17 (95 % CI 2.5-6.9), and -LR 0.11 (95 % CI 0.04-0.3). While five studies investigated right-sided CDH in the ultrasound group, there was only one study in the MRI group. Seven studies included head-to-head comparison between prenatal ultrasound and MRI, of which the diagnostic accuracy appeared comparable in all CDH cases (P = 0.14). Limitations include variation in measurement methodology, reproducibility, as well as heterogeneity, and methodological concerns.

CONCLUSION

The assessment of lung size using antenatal ultrasound appears to have comparable accuracy to that using MRI in assessing the chances of survival in prenatally diagnosed isolated severe CDH undergoing expectant management (i.e., did not undergo fetal surgery). This finding was demonstrated in all cases of CDH and those with left-sided CDH. Future studies should aim at investigating new imaging prognostic markers for both US and MRI in predicting morbidity and mortality.