Noncontrast myocardial T1 mapping using cardiovascular magnetic resonance for iron overload.

Purpose To explore the use and reproducibility of magnetic resonance-derived myocardial T₁ mapping in patients with iron overload. Materials and Methods The research received ethics committee approval and all patients provided written informed consent. This was a prospective study of 88 patients and 67 healthy volunteers. Thirty-five patients underwent repeat scanning for reproducibility. T₁ mapping used the shortened modified Look-Locker inversion recovery sequence (ShMOLLI) with a second, confirmatory MOLLI sequence in the reproducibility group. T₂* was performed using a commercially available sequence. The analysis of the T₂* interstudy reproducibility data was performed by two different research groups using two different methods. Results Myocardial T₁ was lower in patients than healthy volunteers (836 ± 138 msec vs. 968 ± 32 msec, P < 0.0001). Myocardial T₁ correlated with T₂* (R = 0.79, P < 0.0001). No patient with low T₂* had normal T₁, but 32% ( n = 28) of cases characterized by a normal T₂* had low myocardial T₁. Interstudy reproducibility of either T₁ sequence was significantly better than T₂*, with the results suggesting that the use of T₁ in clinical trials could decrease potential sample sizes by 7-fold. Conclusion Myocardial T₁ mapping is an alternative method for cardiac iron quantification. T₁ mapping shows the potential for improved detection of mild iron loading. The superior reproducibility of T₁ has potential implications for clinical trial design and therapeutic monitoring. J. Magn. Reson. Imaging 2015;41:1505-1511. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]