Abstract： Objective To study the diagnostic value of non-contrast T1mapping in left ventricular hypertrophy(LVH).Methods Forty LVH patients(LVH group)including 11 cardiac amyloidosis(CA),19 hypertrophic cardiomyopathy (HCM) and 10 hypertensive heart disease (HHD) patients, and 14 healthy volunteers (control group) were enrolled in this retrospective study between November 2015 and October 2016.All subjects underwent cardiac magnetic resonance(CMR)on a 3 T scanner.The CMR scan protocol included cine sequences, first-pass perfusion, late Gadolinium enhancement (LGE) and non-contrast T1 mapping(MOLLI)prototype sequences.The cardiac morphology was assessed by cine,first-pass perfusion as well as LGE.Left-ventricular end-diastolic wall thickness(EDTH)was assessed for 16 segments,native T1 values were measured in hypertrophic segments. The differences in EDTH and native T1values between LVH group and control group were evaluated using t test. The ANOVA and LSD were used in the comparison of differences among four sub-groups.Sensitivity,specificity,cut-off values and area under the curve (AUC) were derived using receiver-operating characteristics curve (ROC) analysis. Results The EDTH and native T1values in LVH group were significantly higher than those of control group[(16.5±5.2)mm vs.(6.3±1.8)mm,(1 388.6±119.8)ms vs.(1 248.4±58.1)ms,t=28.8 16.4,both P<0.01].Moreover,CA showed significantly higher T1value [(1 495.5 ± 100.9)ms] than that of HCM [(1 342.0 ± 69.2)ms] and HDD [(1 290.7±45.5)ms](F=300.5,P<0.01),and T1values in HCM were also higher than HDD(P<0.01).HCM showed significantly higher EDTH than that of CA and HDD (P<0.01), and EDTH in CA was also higher than HDD (P<0.01). The native T1showed good diagnostic performance between CA and HCM with AUC 0.914,sensitivity 90.1%%,and specificity 84.3%,and cutoff value 1 382.8 ms,between CA and HHD with AUC 0.989,sensitivity 97.0%,specificity 93.5% and cutoff value 1 359.5 ms.Conclusion The elevated native T1values were useful for quantitatively differential diagnosis of LVH.