Optimizing the Diagnostic Assessment of Left Ventricular Noncompaction Cardiomyopathy: The Clinical Value of Cardiac Magnetic Resonance Imaging

Introduction: The current diagnostic criteria for noncompaction of the ventricular myocardium (NVM) remain inconsistent, and comprehensive cardiac magnetic resonance (CMR) imaging data on the disease are limited. Therefore, the purpose of this study is to evaluate the clinical utility of CMR imaging in the diagnosis and functional assessment of patients with NVM. Materials and Methods: Twenty patients with NVM and twenty age- and sex-matched healthy controls (HC) underwent comprehensive CMR imaging. Postprocessing software was used to quantify left ventricular longitudinal strain, both global longitudinal strain (GLS) and strain in the basal, middle, and apical segments (BLS, MLS, and ALS, respectively). Statistical analyses were performed to assess group differences. Results: Compared with the HC group, patients with NVM presented significantly increased left ventricular end-diastolic volume (LVEDV), end-systolic volume (LVESV), stroke volume (LVSV), and myocardial mass index (LVMI) and a significantly reduced left ventricular ejection fraction (LVEF) (all P < 0.001). All NVM patients presented prominent trabeculations and deep intertrabecular recesses in the left ventricle during diastole. Cine imaging revealed direct blood flow communication between the recesses and the ventricular cavity. The myocardium exhibited a thin compacted outer layer (C) and a thickened noncompacted inner layer (NC), with an average NC/C ratio of 2.8 ± 0.5. For these patients, NVM primarily involved the apical and adjacent mid-ventricular free wall segments; in five patients, it also involved the basal segment. Right ventricular noncompaction was observed in five patients, and apical ventricular aneurysms were identified in two patients. Compared with the HC group, the NVM group presented a significantly lower ALS (P < 0.05); however, the BLS, MLS, and GLS values were not significantly different between the groups (P > 0.05). Discussion: Our study demonstrated the feasibility of using CMR imaging to quantitatively assess left ventricular systolic function in NVM patients. The choice of longitudinal strain as a primary parameter was driven by the fact that NVM predominantly affects the endocardial myocardium, particularly the subendocardial fibers, which are primarily longitudinal. As such, longitudinal strain is particularly sensitive for detecting myocardial contractile dysfunction in NVM. Our results indicated that ALS apical longitudinal strain is a more significant marker of contractile dysfunction in NVM than MLS, which was not significantly altered in NVM patients relative to HCs. Conclusion: CMR imaging offers robust diagnostic capabilities for patients with NVM and, when combined with feature tracking, allows the quantitative assessment of left ventricular systolic function. The ALS may serve as a sensitive marker of early myocardial dysfunction and may be clinically important in guiding timely diagnosis and intervention.