MR extracellular volume mapping and non-contrast T1ρ mapping allow early detection of myocardial fibrosis in diabetic monkeys

Abstract

Objective To detect diffuse myocardial fibrosis in different severity levels of left ventricular diastolic dysfunction (DD) in spontaneous type 2 diabetes mellitus (T2DM) rhesus monkeys. Methods Eighteen spontaneous T2DM and nine healthy monkeys were studied. Echocardiography was performed for diastolic function classification. Cardiac magnetic resonance (CMR) imaging was performed to obtain extracellular volume fraction (ECV) maps and T1ρ maps at two different spin-locking frequencies. ECV values, T1ρ values, and myocardial fibrosis index (mFI) values which are based on the dispersion of T1ρ, were calculated. Global peak diastolic longitudinal strain rates (GSrL) were also obtained. Results Echocardiography results showed mild DD in nine T2DM monkeys and moderate DD in the other nine. The global ECV values were significantly different among healthy animals as compared with animals with mild DD or moderate DD, and the ECV values of animals with moderate DD were significantly higher as compared with those of mild DD. The mFI values increased progressively from healthy animals to those with mild DD and then to those with moderate DD. Diastolic function indicators (e.g., early diastolic mitral annulus velocity, GSrL) correlated well with ECV and mFI. Conclusions Monkeys with T2DM exhibit increased ECV, T1ρ, and mFI values, which may be indicative of the expansion of extracellular volume and the deposition of excessive collagen. T1ρ mapping may have the potential to be used for diffuse myocardial fibrosis assessment. Key Points • Monkeys with T2DM exhibit increased ECV, T1ρ, and mFI values, which may be indicative of the expansion of extracellular volume and the deposition of excessive collagen . • The relationship between diastolic dysfunction and diffuse myocardial fibrosis may be demonstrated by imaging markers . • Non-contrast T1ρ mapping may have the potential to be used for diffuse myocardial assessment . Electronic supplementary material The online version of this article (10.1007/s00330-018-5950-9) contains supplementary material, which is available to authorized users.

Quantification correction for free-breathing myocardial T1ρ mapping in mice using a recursively derived description of a T1ρ* relaxation pathway

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Endogenous assessment of myocardial injury with single-shot model-based non-rigid motion-corrected T1 rho mapping

“…Application of T1ρ mapping to CMR has been reported in multiple studies [ 5 – 8 ], mostly to discriminate between infarct and healthy myocardium in swine, mouse and monkey models. These studies raise the interesting question of whether endogenous T1ρ mapping could be a useful adjunct to late gadolinium enhancement (LGE) imaging.…”

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