Histological Validation of measurement of diffuse interstitial myocardial fibrosis by myocardial extravascular volume fraction from Modified Look-Locker imaging (MOLLI) T1 mapping at 3?T

摘要

BackgroundGadolinium (Gd) Extracellular volume fraction (ECV) by Cardiovascular Magnetic Resonance (CMR) has been proposed as a non-invasive method for assessment of diffuse myocardial fibrosis. Yet only few studies used 3?T CMR to measure ECV, and the accuracy of ECV measurements at 3?T has not been established. Therefore the aims of the present study were to validate measurement of ECV by MOLLI T1 mapping by 3?T CMR against fibrosis measured by histopathology. We also evaluated the recently proposed hypothesis that native-T1 mapping without contrast injection would be sufficient to detect fibrosis.Methods31 patients (age?=?58?±?17?years, 77?% men) with either severe aortic stenosis (n?=?12) severe aortic regurgitation (n?=?9) or severe mitral regurgitation (n?=?10), all free of coronary artery disease, underwent 3?T-CMR with late gadolinium enhancement (LGE) and pre- and post-contrast MOLLI T1 mapping and ECV computation, prior to valve surgery. LV biopsies were performed at the time of surgery, a median 13 [1–30] days later, and stained with picrosirius red. Pre-, and post-contrast T1 values, ECV, and amount of LGE were compared against magnitude of fibrosis by histopathology by Pearson correlation coefficients.ResultsThe average amount of interstitial fibrosis by picrosirius red staining in biopsy samples was 6.1?±?4.3?%. ECV computed from pre-post contrast MOLLI T1 time changes was 28.9?±?5.5?%, and correlated (r?=?0.78, p?