Kato, ShingoNakamori, ShiroRoujol, SébastienDelling, Francesca N.Akhtari, ShadiJang, JihyeBasha, Tamer ABerg, SophieKissinger, Kraig V.Goddu, BethManning, WarrenNezafat, Reza2016-12-022016Kato, S., S. Nakamori, S. Roujol, F. N. Delling, S. Akhtari, J. Jang, T. Basha, et al. 2016. “Relationship between native papillary muscle T1 time and severity of functional mitral regurgitation in patients with non-ischemic dilated cardiomyopathy.” Journal of Cardiovascular Magnetic Resonance 18 (1): 79. doi:10.1186/s12968-016-0301-y. http://dx.doi.org/10.1186/s12968-016-0301-y.1097-6647http://nrs.harvard.edu/urn-3:HUL.InstRepos:29626090Background: Functional mitral regurgitation is one of the severe complications of non-ischemic dilated cardiomyopathy (DCM). Non-contrast native T1 mapping has emerged as a non-invasive method to evaluate myocardial fibrosis. We sought to evaluate the potential relationship between papillary muscle T1 time and mitral regurgitation in DCM patients. Methods: Forty DCM patients (55 ± 13 years) and 20 healthy adult control subjects (54 ± 13 years) were studied. Native T1 mapping was performed using a slice interleaved T1 mapping sequence (STONE) which enables acquisition of 5 slices in the short-axis plane within a 90 s free-breathing scan. We measured papillary muscle diameter, length and shortening. DCM patients were allocated into 2 groups based on the presence or absence of functional mitral regurgitation. Results: Papillary muscle T1 time was significantly elevated in DCM patients with mitral regurgitation (n = 22) in comparison to those without mitral regurgitation (n = 18) (anterior papillary muscle: 1127 ± 36 msec vs 1063 ± 16 msec, p < 0.05; posterior papillary muscle: 1124 ± 30 msec vs 1062 ± 19 msec, p < 0.05), but LV T1 time was similar (1129 ± 38 msec vs 1134 ± 58 msec, p = 0.93). Multivariate linear regression analysis showed that papillary muscle native T1 time (β = 0.10, 95 % CI: 0.05–0.17, p < 0.05) is significantly correlated with mitral regurgitant fraction. Elevated papillary muscle T1 time was associated with larger diameter, longer length and decreased papillary muscle shortening (all p values <0.05). Conclusions: In DCM, papillary muscle native T1 time is significantly elevated and related to mitral regurgitant fraction.en-USJournal Article2016-12-0210.1186/s12968-016-0301-y