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

Abstract

BackgroundMyocardial 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.MethodsBalanced 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.ResultsSR 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.ConclusionsSaturation-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.Electronic supplementary materialThe online version of this article (doi:10.1186/s12968-016-0302-x) contains supplementary material, which is available to authorized users.

Simultaneous multislice imaging for native myocardial T1 mapping: Improved spatial coverage in a single breath-hold

“…All MB and SB T 1 mapping were performed at 3T with a single‐shot electrocardiography (ECG)‐triggered FLASH sequence with the following imaging parameters: uniform in‐plane undersampling = 2; FOV = 320 × 320 mm 2 ; spatial resolution = 2.0 × 2.1 mm 2 ; slice thickness = 10 mm; slice gap = 10 mm; partial Fourier = 6/8; number of phase‐encode lines = 69; repetition time = 4.0 ms; echo time = 2.0 ms; flip angle = 10 °; bandwidth = 505 Hz/pixel; linear k‐space ordering; inversion pulse: tan/tanh adiabatic full passage, 2.56 ms ; saturation pulse: four compartment Water Suppression Enhanced through T 1 effect (WET) module . 24 reference lines were acquired in the k‐space center for each image.…”

FASt single‐breathhold 2D multislice myocardial T1 mapping (FAST1) at 1.5T for full left ventricular coverage in three breathholds

“…In these approaches, multiple images with different T 1 ‐weightings are acquired and fit in a pixelwise manner to a physical model of the MR signal evolution . Inversion recovery (IR)‐based approaches such as modified Look–Locker inversion recovery (MOLLI) are commonly used due to their high precision, reproducibility, and map quality . In these techniques, multiple (usually 7–13) 2D single‐shot electrocardiogram (ECG)‐triggered images of the same slice are acquired at different inversion times (TIs) in a single breathhold and used to generate one T 1 map.…”

Assessment of sympathetic reinnervation after cardiac transplantation using hybrid cardiac PET/MRI: A pilot study

“…Other technical issues may arise from MRI. Measuring the ECV on MRI in the short axis located at the base and apex of the LV is not the standard procedure recommended in the guidelines, but this has already been validated in healthy subjects . Higher native T 1 relaxation times over the anterior wall in our cohort might also have been caused by an increased blood flow based on reinnervation, as shown by Reiter et al, who compared intraindividual end‐systolic and end‐diastolic T 1 relaxation times .…”