VALIDITY OF T2 MAPPING IN CHARACTERIZATION OF ARTICULAR CARTILAGE IN THE ANKLE JOINT

Abstract

Introduction: Qualitative evaluation of postoperative outcome in cartilage repair techniques is an issue due to morbidity of bioptic second look. T2 mapping is becoming increasingly popular in the knee, providing information about the histological and biochemical contents of healthy or reparative tissue. Nevertheless, little is known about its applicability to the ankle due to thinner cartilage layer.

Aim of this study was to investigate the validity of T2 mapping in ankle cartilage characterization.

Materials and Methods: 20 healthy volunteers and 30 patients affected by osteochondral lesions of the talus and previously treated by different cartilage repair techniques, were evaluated by T2 mapping. Reparative procedures included microfractures, Autologous Chondrocyte Implantation (open or arthroscopic) and Bone Marrow Derived Cell’s Transplantation. DPFSE with or without fat suppression, T2FSE with or without fat suppression, 3D SPGR and T2-Mapping using a dedicated phased array coil and 1.5 T MR scanner were used as MRI acquisition protocol.

MRI results were correlated with clinical score (AOFAS) in the cases who received a cartilage reconstruction treatment.

Results: A statistically significant correlation (p< 0.05) was shown between MRI and clinical results. A reduced mean T2 value, suggestive for fibrocartilage features, was shown at repair sites in microfractures, whereas no significative differences with healthy hyaline cartilage mean T2 value, were found in other repair techniques with good to excellent clinical score.

Conclusions: T2 mapping demonstrated to be adequate in characterizing cartilage tissue in the ankle. Further studies are required to implement a tool which may over time be a valuable non-invasive alternative to bioptic evaluation.