Repeatability of simultaneous 1H/23Na MR fingerprinting in knee cartilage at 7 T

Motivation: Simultaneous 1H/23Na MRF has potential for assessing pathologies in the knee cartilage. Goal(s): This pilot study aims to evaluate the repeatability of simultaneous 1H/23Na MR fingerprinting (MRF) in knee cartilage of healthy subjects, to establish a baseline for spin densities and relaxation times. Approach: We conducted four 3D 1H/23Na MRF acquisitions in six volunteers using a dual-tuned knee coil at 7T, obtaining sodium and proton maps through offline image reconstruction and MRF dictionary matching. Results: The findings reveal good repeatability (CV around 10%) for proton T1, sodium density, T1, and T2l, while higher CV was observed in proton density, T1 and sodium T2s. Impact: This is the first simultaneous acquisition of multinuclear MRF in knee cartilage at 7T. The pilot study indicates repeatability of measuring sodium and proton spin densities and relaxation times.