BACKGROUND: No study has assessed myocardial T1 and T2 values in patients with beta-thalassemia intermedia (β-TI). PURPOSE: To assess the prevalence of myocardial involvement in β-TI patients by T2* relaxometry and native T1 and T2 mapping and to determine the correlation of myocardial relaxation times with demographic and clinical parameters. STUDY TYPE: Prospective matched-cohort study. SUBJECTS: 42 β-TI patients (27 females, 39.65 ± 12.32 years), enrolled in the Extension-Myocardial Iron Overload in Thalassaemia Network, and 42 age- and sex-matched healthy volunteers (27 females, 40.01 ± 11.36 years) and thalassemia major (TM) patients (27 females, 39.27 ± 11.57 years). FIELD STRENGTH/SEQUENCE: 1.5 T/multi-echo gradient echo, modified Look-Locker inversion recovery, multi-echo fast-spin-echo, cine balanced steady-state-free precession, and late gadolinium enhancement (LGE) sequences. ASSESSMENT: Hepatic, pancreatic, and left ventricular (LV) T2* values, LV native T1 and T2 values, biventricular ejection fractions and volumes, and presence and extent of replacement myocardial fibrosis. STATISTICAL TESTS: Comparisons between two groups were performed with two-sample t tests, Wilcoxon's signed rank tests, or χ RESULTS: β-TI patients had significantly higher LV T2 values than healthy subjects (56.84 ± 4.03 vs. 52.46 ± 2.50 msec, P <
0.0001) and significantly higher LV T1 values than TM patients (1018.32 ± 48.94 vs. 966.66 ± 66.47 msec, P <
0.0001). In β-TI, female gender was associated with significantly increased LV T1 (P = 0.041) and T2 values (P <
0.0001), while splenectomy and presence of regular transfusions were associated with significantly lower LV T1 values (P = 0.014 and P = 0.001, respectively). In β-TI patients, all LV relaxation times were significantly correlated with each other (T2*-T1: P = 0.003
T2*-T2: P = 0.003
T1-T2: P <
0.0001). Two patients with a reduced LV T2* also had a reduced LV T1, while only one had a reduced LV T2. Three patients had a reduced LV T1 but a normal LV T2*
66.7% of the patients had an increased LV T2. All LV relaxation times were significantly correlated with pancreas T2* values (T2*: P = 0.033
T1: P <
0.0001
T2: P = 0.014). No LV relaxation time was associated (P >
0.05) with hepatic iron concentration, biventricular function parameters, or LGE presence. CONCLUSION: The combined use of all three myocardial relaxation times has potential to improve sensitivity in the detection of early/subclinical myocardial involvement in β-Tl patients. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 2.