Joao Tourais ^1,2 Masa Bozic-Iven ^1,2 Yidong Zhao ¹ Qian Tao ¹ Iain Pierce ^3,4 Christian Nitsche ^3,4 George D Thornton ^3,4 Lothar Schad ² Thomas A Treibel ^3,4 Sebastian Weingärtner ^1* Mehmet Akcakaya ^5,6

• ¹ Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Delft, Netherlands
• ² Mannheim Institute for Intelligent Systems in Medicine, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Baden-Württemberg, Germany
• ³ Barts Heart Centre, London, England, United Kingdom
• ⁴ Institute of Cardiovascular Science, Faculty of Population Health Sciences, University College London, London, England, United Kingdom
• ⁵ Department of Electrical and Computer Engineering, College of Science and Engineering, University of Minnesota, Minneapolis, Minnesota, United States
• ⁶ Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, United States

Purpose Evaluate the feasibility of quantification of Relaxation Along a Fictitious Field in the 2 nd rotating frame (RAFF2) relaxation times in the human myocardium at 3T. Methods T RAFF2 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 T RAFF2 maps were obtained after three-parameter exponential fitting. The repeatability of T RAFF2 , T 1 , and T 2 was assessed in phantom via the coefficient of variation (CV) across three repetitions. In seven healthy subjects, T RAFF2 was tested for precision, reproducibility, inter-subject variability, and image quality (IQ) on a Likert scale (1=Nondiagnostic, 5=Excellent). Additionally, T RAFF2 mapping was performed in three patients with suspected cardiovascular disease, comparing it to late gadolinium enhancement (LGE), native T 1 , T 2 , and ECV mapping.In phantom, T RAFF2 showed good repeatability (CV<1.5%) while showing no (R 2 =0.09) and high (R 2 =0.99) correlation with T 1 and T 2 , respectively. Myocardial T RAFF2 maps exhibited overall acceptable image quality (IQ=3.0±1.0) with moderate artifact levels, stemming from off-resonances near the coronary sinus. Average T RAFF2 time across subjects and repetitions was 79.1±7.3ms. Good precision (7.6±1.4%), reproducibility (1.0±0.6%), and low inter-subject variability (10.0±1.8%) were obtained. In patients, visual agreement of the infarcted area was observed in the T RAFF2 map and LGE.Myocardial T RAFF2 quantification at 3T was successfully achieved in a single breathhold with acceptable image quality, albeit with residual off-resonance artifacts. Nonetheless, preliminary clinical data indicate potential sensitivity of T RAFF2 mapping to myocardial infarction detection without the need for contrast agents, but off-resonance artifacts mitigation warrants further investigation.