Myocardial T1-mapping at 3T using saturation-recovery: reference values,precision and comparison with MOLLI

Background: myocardial t1-mapping recently emerged as a promising quantitative method for non-invasive tissue characterization in numerous cardiomyopathies. commonly performed with an inversion-recovery (ir) magnetization preparation at 1.5t,the application at 3t has gained due to increased quantification precision. alternatively,saturation-recovery (sr) t1-mapping has recently been introduced at 1.5t for improved accuracy. thus,the purpose of this study is to investigate the robustness and precision of sr t1-mapping at 3t and to establish accurate reference values for native t1-times and extracellular volume fraction (ecv) of healthy myocardium. methods: balanced steady-state free-precession (bssfp) saturation-pulse prepared heart-rate independent inversion-recovery (sapphire) and saturation-recovery single-shot acquisition (sasha) t1-mapping were compared with the modified look-locker inversion recovery (molli) sequence at 3t. accuracy and precision were studied in phantom. native and post-contrast t1-times and regional ecv were determined in 20 healthy subjects (10 men,27 ± 5 years). subjective image quality,susceptibility artifact rating,in-vivo precision and reproducibility were analyzed. results: sr t1-mapping showed <4 % deviation from the spin-echo reference in phantom in the range of t1 = 100-2300 ms. the average quality and artifact scores of the t1-mapping methods were: molli:3.4/3.6,sapphire:3.1/3.4,sasha:2.9/3.2; (1: poor - 4: excellent/1: strong - 4: none). sapphire and sasha yielded significantly higher t1-times (sapphire: 1578 ± 42 ms,sasha: 1523 ± 46 ms),in-vivo t1-time variation (sapphire: 60.1 ± 8.7 ms,sasha: 70.0 ± 9.3 ms) and lower ecv-values (sapphire: 0.20 ± 0.02,sasha: 0.21 ± 0.03) compared with molli (t1: 1181 ± 47 ms,ecv: 0.26 ± 0.03,precision: 53.7 ± 8.1 ms). no significant difference was found in the inter-subject variability of t1-times or ecv-values (t1: p = 0.90,ecv: p = 0.78),the observer agreement (inter: p > 0.19; intra: p > 0.09) or consistency (inter: p > 0.07; intra: p > 0.17) between the three methods. conclusions: saturation-recovery t1-mapping at 3t yields higher accuracy,comparable inter-subject,inter- and intra-observer variability and less than 30 % precision-loss compared to molli. © 2016 the author(s).