Endogenous assessment of diffuse myocardial fibrosis in patients with T1ρ‐mapping. Issue 1 (16th June 2016) - van Oorschot, Joep W.M.
Abstract : Purpose: Recently, it was shown that a significantly higher T1ρ is found in compact myocardial fibrosis after chronic myocardial infarction. In this study, we investigated the feasibility of native T1ρ ‐mapping for the detection of diffuse myocardial fibrosis in patients with dilated cardiomyopathy (DCM). Materials and Methods: T1ρ ‐mapping was performed on three explanted hearts from DCM patients at 3 Tesla (T). Histological fibrosis quantification was performed, and compared with the T1ρ ‐relaxation times in the heart. Furthermore, twenty DCM patients underwent an MRI at 1.5T. Native T1ρ ‐maps, native T1 ‐maps, and extracellular volume (ECV)‐maps were acquired. Additionally, eight healthy volunteers were scanned for reference values. Results: A significant correlation (Pearson r = 0.49; P = 0.005) was found between ex vivo T1ρ ‐values and fibrosis fraction from histology. Additionally, a significantly higher T1ρ ‐relaxation time (55.2 ± 2.7 ms) was found in DCM patients compared with healthy control subjects (51.5 ± 1.2 ms) ( P = 0.0024). The relation between in vivo T1ρ ‐values and ECV‐values was significant (Pearson r = 0.66). No significant relation was found between native T1 ‐ and ECV‐values in this study ( P = 0.89). Conclusion: This study showed proof of principle for the endogenous detection of diffuse myocardial fibrosis with T1ρ ‐MRI. Ex vivo and in vivo experiments showed promising results that T1ρ ‐MRI can be used to measure the extent of diffuse myocardial fibrosis in the myocardium. Level of Evidence: 2 J. Magn. Reson. Imaging 2017;45:132–138.