Advanced Morphological 3D Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) Scoring Using a New Isotropic 3D Proton-Density, Turbo Spin Echo Sequence With Variable Flip Angle Distribution (PD-SPACE) Compared to an Isotropic 3D Steady-State Free Precession Sequence (True-FISP) and Standard 2D Sequences

Purpose: To evaluate a new isotropic 3D proton-density, turbo-spin-echo sequence with variable flip-angle distribution (PD-SPACE) sequence compared to an isotropic 3D true-fast-imaging with steady-state-precession (True-FISP) sequence and 2D standard MR sequences with regard to the new 3D magnetic resonance observation of cartilage repair tissue (MOCART) score. Materials and Methods: Sixty consecutive MR scans on 37 patients (age: 32.8 +/- 7.9 years) after matrix-associated autologous chondrocyte transplantation (MACT) of the knee were prospectively included. The 3D MOCART score was assessed using the standard 2D sequences and the multiplanar-reconstruction (MPR) of both isotropic sequences. Statistical, Bonferroni-corrected correlation as well as subjective quality analysis were performed. Results: The correlation of the different sequences was significant for the variables defect fill, cartilage interface, bone interface, surface, subchondral lamina, chondral osteophytes, and effusion (Pearson coefficients 0.514-0.865). Especially between the standard sequences and the 3D True-FISP sequence, the variables structure, signal intensity, subchondral bone, and bone marrow edema revealed lower, not significant, correlation values (0.242-0.383). Subjective quality was good for all sequences (P >= 0.05). Artifacts were most often visible on the 3D True-FISP sequence (P < 0.05). Conclusion: Different isotropic sequences can be used for the 3D evaluation of cartilage repair with the benefits of isotropic 3D MRI, MPR, and a significantly reduced scan time, where the 3D PD-SPACE sequence reveals the best results.