Papillary muscle native T1 time is associated with severity of functional mitral regurgitation in patients with non-ischemic dilated cardiomyopathy

Methods Forty DCM patients (55 ± 13 years) and 20 healthy adult control subjects (54 ± 13 years) were enrolled. Slice interleaved T1 mapping sequence (STONE) was employed for the native T1 mapping, which enables acquisition of 5 slices in the short-axis plane within a 90 sec free-breathing scan. For calculating papillary muscle native T1 time, both anterior and posterior papillary muscles were manually traced on custom software (MediaCare, Boston, MA, USA). We measured papillary muscle diameter, length and shortening on cine MRI. Phase contrast images were acquired perpendicular to the proximal ascending aorta to quantify blood flow. Mitral regurgitation volume was calculated as the difference between the LV stroke volume and ascending aorta forward flow. DCM patients were allocated into 2 groups based on the presence or absence of functional mitral regurgitation.