T1, T2, and Fat Fraction Cardiac MR Fingerprinting: Preliminary Clinical Evaluation

Background: Dixon cardiac magnetic resonance fingerprinting (MRF) has been recently introduced to simultaneously provide water T-1, water T-2, and fat fraction (FF) maps. Purpose: To assess Dixon cardiac MRF repeatability in healthy subjects and its clinical feasibility in a cohort of patients with cardiovascular disease. Population: T1MES phantom, water-fat phantom, 11 healthy subjects and 19 patients with suspected cardiovascular disease. Study Type: Prospective. Field Strength/Sequence: 1.5T, inversion recovery spin echo (IRSE), multiecho spin echo (MESE), modified Look-Locker inversion recovery (MOLLI), T-2 gradient spin echo (T-2-GRASE), 6-echo gradient rewound echo (GRE), and Dixon cardiac MRF. Assessment: Dixon cardiac MRF precision was assessed through repeated scans against conventional MOLLI, T-2-GRASE, and PDFF in phantom and 11 healthy subjects. Dixon cardiac MRF native T-1, T-2, FF, postcontrast T-1 and synthetic extracellular volume (ECV) maps were assessed in 19 patients in comparison to conventional sequences. Measurements in patients were performed in the septum and in late gadolinium enhanced (LGE) areas and assessed using mean value distributions, correlation, and Bland-Altman plots. Image quality and diagnostic confidence were assessed by three experts using 5-point scoring scales. Statistical Tests: Paired Wilcoxon rank signed test and paired t-tests were applied. Statistical significance was indicated by *(P < 0.05). Results: Dixon cardiac MRF showed good overall precision in phantom and in vivo. Septal average repeatability was similar to 23 msec for T-1, similar to 2.2 msec for T-2, and similar to 1% for FF. Biases in healthy subjects/patients were measured at +37 msec*/+60 msec* and -8.8 msec*/-8 msec* when compared to MOLLI and T-2-GRASE, respectively. No statistically significant differences in postcontrast T-1 (P = 0.17) and synthetic ECV (P = 0.19) measurements were observed in patients. Data Conclusion Dixon cardiac MRF attained good overall precision in phantom and healthy subjects, while providing coregistered T-1, T-2, and fat fraction maps in a single breath-hold scan with similar or better image quality than conventional methods in patients.

Automated summary

Dixon cardiac MRF demonstrated good precision and repeatability in both phantom and in vivo studies. Image quality was comparable to conventional methods, with no significant differences observed in measurements among patients.