Subvoxel QSM of human knee cartilage: a preliminary study

Motivation: Subvoxel QSM could be beneficial for assessing the knee cartilage but requires two separate sequences for reconstruction by using APART-QSM. Goal(s): To achieve subvoxel QSM reconstruction of knee cartilage in a single scan. Approach: A multi-contrast framework was used to simultaneously estimate $$$T_1$$$, $$$T_2$$$ and $$$T_2^{*}$$$ mapping in one scan. The magnitude and phase images were generated based on the signal equation. The preprocessed phase and $$$R_2^{'}$$$(=$$$1/{T_2^*}$$$-$$$1/{T_2}$$$) were used for subvoxel QSM reconstruction. The results were compared with conventional approach using two sequences (GRE+MSE). Results: The subvoxel QSM results using the multi-contrast framework have good agreement with the conventional condition. Impact: The diamagnetic and paramagnetic susceptibility source separation of the knee cartilage could be achieved in a single scan using a multi-contrast framework. This technique can provide specific information to assess the tissue magnetic properties of the knee cartilage.