Evaluation of age-related interstitial myocardial fibrosis with cardiac magnetic resonance contrast-enhanced T₁ mapping: MESA (Multi-Ethnic Study of Atherosclerosis)

Objectives This study sought to determine the relationship of cardiovascular magnetic resonance (CMR) measures of tissue composition to age in the Multi-Ethnic Study of Atherosclerosis (MESA). Background Animal and human studies have demonstrated increased collagen deposition in senescent hearts. New CMR indices of tissue composition by using T₁ mapping are sensitive to the presence of myocardial fibrosis. Methods A total of 1,231 study participants (51% women; age range 54 to 93 years) of the MESA cohort were evaluated with T₁ mapping by using 1.5-T CMR scanners. None of the participants had focal scar on delayed enhancement CMR. Single-slice T ₁ mapping was performed at the midventricular level before and at 12- and 25-min delay after administration of gadolinium contrast by using a modified Look-Locker inversion recovery sequence. The partition coefficient was determined by the slope of the linear relationship of (1/T_1myo vs. 1/T_1blood). The extracellular volume fraction (ECV) was derived accounting for the hematocrit level. Multivariable regression analyses were performed, adjusting for traditional risk factors and left ventricular structure. Results Women had significantly greater partition coefficient, ECV, and precontrast T₁ than men, as well as lower post-contrast T ₁ values (all p < 0.05). In general, linear regression analyses demonstrated that greater partition coefficient, pre-contrast T₁ values, and ECV were associated with older age in men (multivariate regression coefficients = 0.01; 5.9 ms; and 1.04% per 10 years' change; all p < 0.05). ECV was also significantly associated with age in women after multivariable adjustments. Conclusions CMR parameters that have been associated with myocardial fibrosis were related to older age in the MESA study. Women had higher ECV than men but less ECV change over time.