The influences of different spatial resolutions on the characteristics of T2 relaxation times in articular cartilage: A coarse-graining study of the microscopic MRI data

Microscopic MRI (μMRI) T2 data from canine cartilage at different tibial locations were analyzed to investigate the influences of spatial resolution and pixel position on the T2 sensitivity to osteoarthritis (OA). Five experimental factors were investigated: inaccurate pixel position, different pixel resolutions, different specimen orientations in the magnetic field, topographical variations over the tibial surface, and different OA stages. A number of significant trends were identified in this analysis, which shows the subtle but substantial influences to our abilities of detecting OA due to T2 changes. In particular, any deviation in locating the cartilage pixels may result in erratic values near the cartilage surface. Significant differences were found in T2 values between nearly any two comparison-groups under all resolutions both in the meniscus-covered and uncovered areas, which were also showed interaction between the OA degradation stages. This multi-resolution project should help to improve the detection sensitivities of MRI towards cartilage degeneration.