Mitral Annular Disjunction Assessed Using Cardiac MR Imaging in Pediatric Patients

Background/Objectives: Mitral annular disorders constitute a heterogeneous group of structural abnormalities that can significantly influence morbidity and mortality in both adult and pediatric populations. Advances in cardiac magnetic resonance (CMR) imaging have refined the ability to characterize these disorders with high spatial resolution and reproducibility. Among them, mitral annular disjunction (MAD) and mitral valve prolapse (MVP) have emerged as interrelated entities implicated in valvular dysfunction, arrhythmogenesis, and myocardial remodeling. This study aimed to determine the prevalence of MAD in a pediatric cohort, explore its association with MVP, and delineate related CMR findings, including myocardial fibrosis. Methods: A retrospective review was conducted in 295 pediatric patients who underwent clinically indicated CMR between September 2022 and June 2025. Echocardiographic and CMR data were systematically compared for the detection of MAD, MVP, and mitral regurgitation (MR). MAD length and mitral annular measurements were obtained from two-chamber and left ventricular outflow tract (LVOT) cine sequences. Late gadolinium enhancement (LGE) was evaluated to identify myocardial fibrosis. Results: MAD was detected more frequently by means of CMR than echocardiography (23.2% vs. 9.3%), as was MVP (34.2% vs. 22.4%), whereas MR was more often observed on echocardiography (31.2% vs. 15.2%). Inter-modality agreement was moderate for MAD, moderate-to-substantial for MVP, and fair for MR. LGE was identified only in patients with concomitant MAD and MVP, suggesting limited myocardial involvement in isolated MAD. Conclusions: CMR demonstrates superior sensitivity in detecting MAD and MVP compared with echocardiography and allows for early recognition of systolic-diastolic annular dissociation before advanced myocardial remodeling occurs. These findings underscore the clinical utility of CMR as a complementary modality for comprehensive assessment, risk stratification, and follow-up of pediatric patients with suspected mitral annular abnormalities.