Endogenous assessment of late gadolinium enhancement grey zone in patients with non-ischaemic cardiomyopathy with T1ρ and native T1 mapping

Aims This study aims to validate and compare the feasibility of T1 rho and native longitudinal relaxation time (T1) mapping in detection of myocardial fibrosis in patients with non-ischaemic cardiomyopathy, focusing on the performance of both methods in identifying late gadolinium enhancement (LGE) grey zone. Methods and results Twenty-seven hypertrophic cardiomyopathy (HCM) patients, 16 idiopathic dilated cardiomyopathy (DCM) patients, and 18 healthy controls were prospectively enrolled for native T1 and T1 rho mapping imaging and then all the patients underwent enhancement scan for LGE extent and extracellular volume (ECV) values. In LGE positive patients, the LGE areas were divided into LGE core (6 SDs above remote myocardium) and grey zone (2-6 SDs above remote myocardium) according to the signal intensity of LGE. Both HCM and DCM patients showed significantly higher native T1 values and T1 rho values than controls no matter the presence of LGE (all P< 0.01). There were significant differences in native T1 and T1 rho values among four different types of myocardia (LGE core, grey zone, remote area and control, P< 0.0001). However, the T1 rho values of grey zone were significantly higher than control (P< 0.01), while the native T1 values were not (P= 0.089). T1 rho values were significantly associated with both native T1 values (r= 0.54, P< 0.001) and ECV values (r= 0.54, P< 0.001). Conclusion T1. mapping is a feasible method to detect myocardial fibrosis in patients with non-ischaemic cardiomyopathy no matter the presence of LGE. Compared with native T1, T1 rho may serve as a better discriminator in the identification of LGE grey zone. [GRAPHICS] .