Fetal cardiovascular magnetic resonance feature tracking myocardial strain analysis in congenital heart disease.

Background: Cardiovascular magnetic resonance (CMR) is an emerging imaging modality for assessing the anatomy and function of the fetal heart in congenital heart disease (CHD). This study aimed to evaluate myocardial strain using fetal CMR feature tracking (FT) in different subtypes of CHD.

Methods: Fetal CMR FT analysis was retrospectively performed on four-chamber cine images acquired with Doppler ultrasound gating at 3T. Left ventricular (LV) global longitudinal strain (GLS), LV global radial strain (GRS), LV global longitudinal systolic strain rate, and right ventricular (RV) GLS were quantified using dedicated software optimized for fetal strain analysis. Analysis was performed in normal fetuses and different CHD subtypes (d-transposition of the great arteries [dTGA], hypoplastic left heart syndrome [HLHS], coarctation of the aorta [CoA], tetralogy of Fallot [TOF], RV-dominant atrioventricular septal defect [AVSD], and critical pulmonary stenosis or atresia [PS/PA]). Analysis of variance with Tukey post-hoc test was used for group comparisons.

Results: A total of 60 fetuses were analyzed (8/60 (13%) without CHD, 52/60 (87%) with CHD). Myocardial strain was successfully assessed in 113/120 ventricles (94%). Compared to controls, LV GLS was significantly reduced in fetuses with HLHS (-18.6±2.7% vs -6.2±5.6%; p<0.001) and RV-dominant AVSD (-18.6±2.7% vs -7.7±5.0%; p = 0.003) and higher in fetuses with CoA (-18.6±2.7% vs -25.0±4.3%; p = 0.038). LV GRS was significantly reduced in fetuses with HLHS (25.7±7.5% vs 11.4±9.7%; p = 0.024). Compared to controls, RV GRS was significantly reduced in fetuses with PS/PA (-16.1±2.8% vs -8.3±4.2%; p = 0.007). Across all strain parameters, no significant differences were present between controls and fetuses diagnosed with dTGA and TOF.

Conclusion: Fetal myocardial strain assessment with CMR FT in CHD is feasible. Distinct differences are present between various types of CHD, suggesting potential implications for clinical decision-making and prognostication in fetal CHD.