Impact of high field (3.0 T) magnetic resonance imaging on diagnosis of osteochondral defects in the ankle joint.

OBJECTIVE: To evaluate high field magnetic resonance (MR) imaging for imaging of osteochondral defects. MATERIALS AND METHODS: Nine osteochondral defects were simulated in three cadaveric talus specimens using a diamond drill. All specimens were examined on a 1.0 T MR unit and a 3.0 T MR unit. A T2-weighted turbo spin-echo (TSE) sequence with a 2 mm slice thickness and a 256 x 256 matrix size was used on both scanners. The visibility of the osteochondral separation and the presence of susceptibility artifacts at the drilling bores were scored on all images. RESULTS: Compared to the 1.0 T MR unit, the protocol on the 3.0 T MR unit allowed a better delineation of the disruption of the articular cartilage and a better demarcation of the subchondral defect. Differences regarding the visualization of the subchondral defect were found to be statistically significant (P<0.05). Differences with regard to susceptibility artifacts at the drilling bores were not statistically significant (P>0.05). The average SNR was higher using 3.0 T MRI (SNR=12), compared to 1.0 T MRI (SNR=7). CONCLUSION: High field MRI enables the acquisition of images with sufficient resolution and higher SNR and has therefore the potential to improve the staging of osteochondral defects.

[Diagnostic imaging of cartilage replacement therapy]. / Bildgebende Diagnostik von Knorpelersatztherapien.

Over the past decade a number of surgical interventions for durable cartilage repair have been developed. For the long-term follow-up of this procedures clinical scores and the morphological and biochemical evaluation of biopsies taken during arthroscopy are used.Magnetic resonance imaging is a useful noninvasive tool for the evaluation of the morphologic status of the cartilage repair tissue throughout the postoperative period. The MR imaging appearance of the most important cartilage transplantation techniques, such as autologous osteochondral transplantation, autologous chondrocyte implantation and matrix-based autologous chondrocyte implantation are described and possible complications of each technique are mentioned. The importance of new MR techniques such as high-resolution morphologic imaging and possible visualization of biochemical information of cartilage repair tissue is discussed.