Abstract
PURPOSE: To develop a method for abdominal simultaneous 3D water T1 ( wT1 ) and T2 ( wT2 ) mapping with isotropic resolution using a free-breathing Cartesian acquisition with spiral profile ordering (CASPR) at 3 T. METHODS: The proposed data acquisition combines a Look-Locker scheme with the modified BIR-4 adiabatic preparation pulse for simultaneous wT1 and wT2 mapping. CASPR is employed for efficient and flexible k-space sampling at isotropic resolution during free breathing. The imaging pipeline includes subspace reconstruction, water-fat separation, and B0 -specific dictionary matching. The proposed method was validated in a water-fat relaxometry phantom using spin echo-based reference techniques and was compared with MOLLI T1 and GRASE T2 mapping in 10 volunteers. The method's flexibility was assessed at isotropic resolutions of 2.5, 3, and 3.5 mm, with corresponding scan times of 7:19, 5:23, and 3:52 min. Additionally, the method was applied to 9 oncological patients with abdominal pathologies. RESULTS: Phantom experiments demonstrated good agreement between the proposed method and spin echo-based reference techniques across a wide range of wT1 and wT2 values. The volunteer study assessed in vivo quantification performance and demonstrated the flexibility of the proposed method at different spatial resolutions. The 3 mm method was successively performed in patients with abdominal pathologies, whereby lesions with diameters below 1 cm could be assessed. CONCLUSION: The proposed Look-Locker-based method using CASPR enables efficient, flexible, and simultaneous wT1 and wT2 mapping at isotropic resolution in a fixed scan time during free breathing.