Comparison of different cardiovascular magnetic resonance sequences for native myocardial T1 mapping at 3T

Background: t1 mapping based on cardiovascular magnetic resonance (cmr) is a novel approach using the magnetic relaxation t1 time as a quantitative marker for myocardial tissue composition. various t1 mapping sequences are being used,with different strengths and weaknesses. data comparing different sequences head to head however are sparse. methods: we compared three t1 mapping sequences,shmolli,molli and sasha in phantoms and in a mid-ventricular slice of 40 healthy individuals (mean age 59 ± 7 years,45 % male) with low (68 %) or moderate cardiovascular risk. we calculated global and segmental t1 in vivo through exponential curve fitting and subsequent parametric mapping. we also analyzed image quality and inter-observer reproducibility. results: there was no association of t1 with cardiovascular risk groups. t1 however differed significantly depending on the sequence,with sasha providing consistently higher mean values than shmolli and molli (1487 ± 36 ms vs. 1174 ± 37 ms and 1199 ± 28 ms,respectively; p < 0.001). this difference between sequences was much smaller in phantom measurements. in patients,segmental values were lower in the anterior wall for all sequences. image quality,in general good for the steady-state-free-precession readouts in all sequences,was lower for sasha parametric maps. on multivariate regression analysis,a longer t1 measured by molli was correlated with lower ejection fraction and female gender. inter-observer variability as assessed by intra-class correlation coefficients was excellent for all sequences (shmolli: 0.995; molli: 0.991; sasha: 0.961; all p < 0.001). conclusion: in a cross-sectional population with low to moderate cardiovascular risk,we observed a variation in t1 mapping results between inversion-recovery vs. saturation-recovery sequences in vivo,which were less evident in phantom images,despite a small interobserver variability. thus,physiological factors,most likely related to b1 inhomogeneities,and tissue-specific properties,like magnetization transfer,that impact t1 values in vivo,render phantom validation insufficient,and have to be further investigated for a better understanding of the clinical utility of different t1 mapping approaches. trial registration: “canadian alliance for healthy hearts and minds” - clinicaltrials.gov nct02220582 ; registered august 18,2014. © 2016 the author(s).