Objective:To apply cardiovascular magnetic resonance (CMR) to quantitatively evaluate the morphology and tissue characteristics of thoracic skeletal muscle (TSM) in patients with Danon disease and hypertrophic cardiomyopathy (HCM), in order to provide auxiliary differential diagnostic information.Methods:A retrospective study was conducted on 15 Danon disease patients (Danon disease group) who completed CMR examination, and 15 HCM patients (HCM group) and 15 healthy volunteers (control group) who were matched by gender and age were compared. TSM (pectoralis major, pectoralis minor, erector spinae, and subscapularis) area index (TSMAi), T1 relaxation time of four groups, and extracellular volume (ECV) of skeletal muscles of two groups (pectoralis major and subscapularis) were measured for all subjects. Single factor analysis of variance and KruskalWallis test were used to compare three sets of values.Results:The total TSMAi of the Danon disease group was lower than that of the HCM group and the control group [(15.37±3.28)cm 2/m 2 vs (23.02±3.88)cm 2/m 2 vs (22.33±4.67)cm 2/m 2, P<0.001], and the TSMAi of each TSM was also lower than that of the HCM group and the control group (all P<0.05). There was no statistically significant difference in TSMAi between the HCM group and the control group (all P>0.05). The native T1 values of the pectoralis major muscle in the Danon disease group and HCM group were higher than those in the control group (all P<0.05). The ECV of the pectoralis major muscle and subscapularis muscle in the Danon disease group were higher than those in the HCM group and control group, and the enhanced T1 values were lower than those in the HCM group and control group (all P<0.05); There was no statistically significant difference in ECV and the enhanced T1 values between the HCM group and the control group ( P>0.05). Conclusions:The application of CMR can effectively evaluate the changes in TSM morphology and tissue characteristics in Danon disease patients. Compared with HCM patients, Danon disease patients showed significant atrophy of TSM with increased extracellular volume. CMR provides a quantitative reference for TSM in the differential diagnosis of the two.

Cardiovascular disease is the leading cause of death among Chinese residents, and non-invasive imaging technology has important value in the diagnosis and treatment of cardiovascular disease. Cardiac magnetic resonance (CMR) can characterize cardiac pathophysiological information from multiple dimensions, including cardiac structure, function, tissue characteristics, and microstructure, through multi parameter and multi sequence " one-stop" imaging. This article will focus on new technologies such as CMRT1 mapping, feature tracking, and diffusion tensor imaging, and explain their applications and progress in the diagnosis, efficacy monitoring, and prognosis prediction of various myocardial lesions such as non ischemic heart disease and ischemic heart disease.