Quantification of T sub(2) relaxation changes in articular cartilage with in situ mechanical loading of the knee

To devise a method for producing in vivo MRI images of the knee under physiologically significant loading, and to compare and evaluate the changes in cartilage characteristics before and during in situ compression of the knee. A total of 26 asymptomatic subjects were imaged on a 1.5 Tesla Philips Intera scanner using a commercially available knee coil. Routine anatomical images were followed by T sub(2) map acquisition. These scans were repeated following in situ compression of the knee using a MR compatible loading jig. Following loading to body weight, several regions of femoral cartilage show early alteration of T sub(2) relaxation time, most significantly in the medial and lateral peripheral zones. There were no significant changes in the tibial cartilage. The results establish the feasibility of measuring changes on MRI with in situ axial loading.