Goetz Hannes Welsch MD, Abstract Co-Author: Nothing to Disclose

Lukas Zak, Abstract Co-Author: Nothing to Disclose

Tallal Charles Mamisch MD, Presenter: Consultant, Siemens AG

Andreas Mauerer, Abstract Co-Author: Nothing to Disclose

Stefan Marlovits MD, Abstract Co-Author: Nothing to Disclose

Siegfried Trattnig MD, Abstract Co-Author: Nothing to Disclose

To use the capabilities of new isovoxel sequences and their 3D multiplanar-reconstruction (MPR) in the monitoring after cartilage repair, the 3D magnetic resonance observation of cartilage repair tissue (MOCART) scoring system was recently introduced. The purpose of this study was to evaluate a new isotropic 3D proton-density, turbo-spin-echo with variable flip-angle distribution (PD-SPACE) sequence compared to an isotropic 3D true-fast-imaging with steady-state-precession (True-FISP) sequence and to a set of 2D standard MR sequences in their depiction of the 3D-MOCART score.

Sixty consecutive MR scans on 37 patients (32.8±7.9 years) during clinical routine at standard follow-up intervals after matrix-associated autologous chondrocyte transplantation (MACT) of the knee at 3T were prospectively included. The new 3D-MOCART score with eleven variables was assessed using the standard 2D sequences (~15minutes) and the multiplanar-reconstruction (MPR) of both isotropic sequences (3D-PD-SPACE~7minutes; 3D-True-FISP~6minutes). Statistical correlation as well as subjective quality analysis was performed.

The correlation between the 3D-MOCART scoring performed by the different sequences was highly significant for the variables 1)defect fill, 2)cartilage interface, 3)bone interface, 4)surface, 7)subchondral lamina, 8)chondral osteophyte, and 11)effusion (Pearson-coefficients 0.514 to 0.865 (p<0.001)). The variables 5)structure, 6)signal intensity, 9)bone marrow edema, and 10)subchondral bone showed lower correlations with best results in between the standard sequences and the 3D-PD-SPACE sequence and in between the 3D-True-FISP sequence and the 3D-PD-SPACE sequence (0.307 to 0.633 (p=0.016 to p<0.001). Grading of subjective quality revealed good results for all sequences (p≥0.05). Artifacts were most often visible on the 3D-True-FISP sequence (p<0.05).

Different isotropic sequences can be used for the 3D evaluation of cartilage repair tissue with the benefits of isotropic 3D-MRI, MPR and significantly reduced scan time. The 3D-PD-SPACE sequence reveals best results due to a better performance in the subchondral bone and because of the suppression of susceptibility artifacts produced by implantation and previous surgeries.

In the depiction of cartilage repair tissue and its adjacent structures, by the MPR of isotropic 3D sequences, enormous time savings can be performed.

Welsch, G, Zak, L, Mamisch, T, Mauerer, A, Marlovits, S, Trattnig, S, Comparison of a New Isotropic 3D Proton-density, Turbo Spin Echo Sequence (PD-SPACE) to a 3D Steady State Free Precession Sequence (True-FISP) and Standard 2D Sequences Based on the 3D- MR Observation of Cartilage Repair Tissue (MOCART) Score.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9004510.html