BackgroundTo investigate the diagnostic performance of native cardiac magnetic resonance (CMR) T1 and T2 mapping for cardiac iron overload (CIO) in thalassemia patients. MethodsAll thalassemia patients who underwent CMR were enrolled on a clinical 1.5T scanner. Native T1 mapping with the Modified Look-Locker Inversion recovery (MOLLI) technique, T2 mapping using a black-blood multi-echo spin-echo technique, and conventional T2* mapping using multi-echo gradient-echo techniques were performed. CIO was defined by a T2* of <20ms; while severe CIO was considered as <10ms. ResultsA total of 200 patients were enrolled in the study (23.9±14.6years old [mean±SD], 102 male). Among these, 8 patients (4.0%) had CIO. Both native T1 and T2 times were significant different among patients with no CIO, mild-to-moderate CIO, and severe CIO (1012.7±57.7 vs. 846.4±34.4 vs 601.3±34.6ms for T1, p<0.05; 59.6±6.5 vs. 48.7±2.5 vs. 32.8±1.2ms for T2, p<0.05). The best cut-off values for detection of CIO were 887 and 52ms for T1 and T2, respectively. This yielded a sensitivity, specificity and area under the curve (AUC) of 100%, 98.4% and 0.997 respectively for T1, in comparison to 100%, 88.8% and 0.961 respectively for T2. ConclusionsNative T1 mapping can differentiate between severe, mild-to-moderate, and no CIO, which appears to be a promising technique for detection and assessment of myocardial iron.