Rosette Cardiac MR Fingerprinting for Simultaneous T 1 , T 2 , T2*, and Fat Fraction Mapping Using a Multi‐Echo Deep Image Prior Reconstruction

ABSTRACT Purpose Quantitative mapping of cardiac tissue properties is used clinically in diagnosis and monitoring of a wide variety of cardiac pathologies. Cardiac Magnetic Resonance Fingerprinting (cMRF) enables rapid and simultaneous quantification of multiple parameters in the myocardium from a single scan. In this work, a multi‐echo cMRF acquisition is combined with a deep image prior framework to reconstruct cardiac T 1 , T 2 , , and fat fraction maps. Methods A 2D, single‐breathhold, ECG‐gated rosette trajectory cMRF sequence was deployed to sensitize the signal to T 1 , T 2 , , and fat off‐resonance effects. Data were processed using a deep image prior reconstruction trained with the cMRF encoding model to generate images consistent with the acquired k‐space data. These images were used in curve fitting and pattern matching algorithms to generate T 1 , T 2 , and fat fraction maps. The technique was validated using numerical simulations, standard phantoms, and 28 healthy subjects. Results In phantoms, good agreement was observed between the proposed technique and gold‐standard reference measurements. In healthy subjects, measurements made with the deep image prior (DIP) reconstruction agreed with clinical cardiac measurements and demonstrated smaller voxel‐level variance in a healthy population compared to iterative low‐rank and direct matching reconstructions. Conclusion The multi‐echo cMRF acquisition coupled with a DIP reconstruction enables the simultaneous quantification of T 1 , T 2 , , and fat in the heart and demonstrates good agreement with conventional mapping approaches in phantom and in vivo experiments. Additionally, the DIP reconstruction provides accurate measurements with a lower voxel‐level variance compared with direct gridding and iterative low‐rank reconstruction methods.