RESUMO
OBJECTIVE: To compare direct evaluation of cartilage with high resolution MRI (hrMRI) to indirect cartilage evaluation using MRI inter-bone distance in hand OA patients and healthy controls. DESIGN: 41 hand OA patients and 18 healthy controls underwent hrMRI of the 2nd and 3rd metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints. The images were read by two independent readers using OMERACT hand OA MRI inter-bone distance score (0-3 scale) and a new hrMRI cartilage score with direct evaluation of the cartilage (0-3 scale). Inter-reader and intra-reader reliability was calculated using exact and close agreement and kappa values. The prevalence of abnormal scores and agreement between methods was assessed in both hand OA patients and healthy controls. RESULTS: The intra- and inter-reader reliability of both scores was comparable, with exact agreement in 73-83% and close agreement in 95-100%. In hand OA patients 27% of 161 joints had both cartilage damage and loss of inter-bone distance, cartilage damage by hrMRI only was present in 20% of joints and reduced inter-bone distance only in 4% of joints. In the healthy controls, 1 of 71 joints were scored as abnormal by both hrMRI and inter bone distance scoring, 1 joint was scored as abnormal using the hrMRI cartilage score only, whereas 15% of joints had only reduced inter bone distance. CONCLUSIONS: Direct cartilage evaluation of MCP and PIP joints using hrMRI has a good reliability, and the higher prevalence of hrMRI cartilage damage in hand OA patients and the lower prevalence in healthy controls in comparison to evaluation of inter-bone distance suggests a better validity.