Feasibility of relaxation along a fictitious field in the 2nd rotating frame (T_RAFF2) mapping in the human myocardium at 3 T

Purpose: Evaluate the feasibility of quantification of Relaxation Along a Fictitious Field in the 2nd rotating frame (RAFF2) relaxation times in the human myocardium at 3 T. Methods: (Formula presented.) mapping was performed using a breath-held ECG-gated acquisition of five images: one without preparation, three preceded by RAFF2 trains of varying duration, and one preceded by a saturation prepulse. Pixel-wise (Formula presented.) maps were obtained after three-parameter exponential fitting. The repeatability of (Formula presented.), (Formula presented.), and (Formula presented.) was assessed in phantom via the coefficient of variation (CV) across three repetitions. In seven healthy subjects, (Formula presented.) was tested for precision, reproducibility, inter-subject variability, and image quality (IQ) on a Likert scale (1 = Nondiagnostic, 5 = Excellent). Additionally, (Formula presented.) mapping was performed in three patients with suspected cardiovascular disease, comparing it to late gadolinium enhancement (LGE), native (Formula presented.), (Formula presented.), and ECV mapping. Results: In phantom, (Formula presented.) showed good repeatability (CV < 1.5%) while showing no ( (Formula presented.) ) and high ( (Formula presented.) ) correlation with (Formula presented.) and (Formula presented.), respectively. Myocardial (Formula presented.) maps exhibited overall acceptable image quality (IQ = 3.0 (Formula presented.) 1.0) with moderate artifact levels, stemming from off-resonances near the coronary sinus. Average (Formula presented.) time across subjects and repetitions was 79.1 (Formula presented.) 7.3 ms. Good precision (7.6 (Formula presented.) 1.4%), reproducibility (1.0 (Formula presented.) 0.6%), and low inter-subject variability (10.0 (Formula presented.) 1.8%) were obtained. In patients, visual agreement of the infarcted area was observed in the (Formula presented.) map and LGE. Conclusion: Myocardial (Formula presented.) quantification at 3 T was successfully achieved in a single breath-hold with acceptable image quality, albeit with residual off-resonance artifacts. Nonetheless, preliminary clinical data indicate potential sensitivity of (Formula presented.) mapping to myocardial infarction detection without the need for contrast agents, but off-resonance artifacts mitigation warrants further investigation.