Initial evidence of presence of papillary muscle diffuse fibrosis in patients with cardiomyopathy

Background The left ventricular (LV) papillary muscles (PM) are important structure for mitral valve complex. Previous studies by echocardiography demonstrated that PM function was impaired in patients with hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). Native T1 mapping has emerged as a noninvasive magnetic resonance (MR) imaging method to assess LV diffuse myocardial fibrosis without using contrast agent. The aims of this study were to evaluate feasibility and reproducibility of PM native T1 measurement, and to compare PM T1 times between cardiomyopathy patients and controls subjects. Methods Seventeen cardiomyopathy patients (11 HCM; 6 DCM, age: 57 ± 15 years) and 16 control subjects (age: 50 ± 15 years) were enrolled. Native T1 mapping images were acquired with MOLLI (Messroghli DR et al. MRM 2004) sequence in 3 short-axis planes (basal, mid and apical slices) using an ECG-triggered single-shot acquisition with a balanced SSFP readout (TR, 3.1; TE, 1.5; FA, 35°; FOV, 360 × 337 mm; acquisition matrix, 188 × 135; voxel size, 1.9 × 2.5 mm; slice thickness, 8 mm). All data were corrected for motion (Roujol S et al. MRM 2014). Measurement of PM T1 was performed both in anterior PM and posterior PM in all subjects. Intra-observer and interobserver reproducibility was assessed by 2 readers in 20 PMs from 10 control subjects. Repeatability coefficients