Value of the Newly Designed Major and Minor Checklists in Diagnosis of Congenital Cardiovascular Disease and Associated Malformation: New Era of Fetal Cardiac MRI.

RATIONALE AND OBJECTIVES: Fetal echocardiography is the standard, rapid, affordable, and noninvasive modality for prenatal assessment of suspected congenital heart disease. Fetal cardiac magnetic resonance imaging (FCMRI) has emerged as a valuable adjunct, particularly when ultrasound is limited by maternal obesity, uterine fibroids, oligohydramnios, fetal malposition, or late-gestational acoustic shadowing. Consequently, this study aimed to evaluate the diagnostic utility of a newly proposed structured major/minor checklist system for FCMRI interpretation. By correlating structured FCMRI interpretations with postnatal echocardiographic outcomes, we assess the framework's reliability in characterizing structural cardiovascular anomalies, particularly when initial ultrasound evaluation is suboptimal. MATERIALS AND METHODS: Between May 2024 and November 2025, an initial cohort of 60 pregnant women was screened, yielding 52 singleton pregnancies with suspected fetal cardiac anomalies. These cases were prospectively evaluated with fetal echocardiography and FCMRI. Image interpretation was performed by two radiologists experienced in prenatal imaging and one pediatric cardiologist. Postnatal confirmation was available for 40 live-born infants; 12 intrauterine fetal death cases were excluded from postnatal diagnostic-performance analysis. RESULTS: Based on postnatal echocardiography, both modalities demonstrated high diagnostic performance. Fetal echocardiography yielded slightly higher sensitivity than FCMRI (96.5% vs. 93.1%), whereas FCMRI exhibited higher specificity (100% vs. 81.8%) and overall diagnostic accuracy (95.0% vs. 92.5%). Notably, FCMRI demonstrated a significantly higher overall concordance with postnatal echocardiography compared to fetal echocardiography for ductus-dependent critical lesions (90.0% vs. 77.5% total agreement). This superior concordance for FCMRI was particularly pronounced in identifying emergency ductus-dependent lesions (72.7% vs. 36.4% agreement in positive cases), alongside higher exact concordance in normal, conotruncal, and hypoplastic heart-spectrum categories, whereas fetal echocardiography showed higher concordance in tetralogy of Fallot and Ebstein anomaly. Both modalities showed similar concordance for atrioventricular septal defects. CONCLUSION: FCMRI is a useful complementary adjunct to fetal echocardiography, improving diagnostic confidence in complex cases and supporting prenatal counseling, delivery planning, and postnatal management.