Quantification of T2 relaxation changes in articular cartilage with in situ mechanical loading of the knee

Purpose 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. Material and Methods 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 T2 map acquisition. These scans were repeated following in situ compression of the knee using a MR compatible loading jig. Results Following loading to body weight, several regions of femoral cartilage show early alteration of T2 relaxation time, most significantly in the medial and lateral peripheral zones. There were no significant changes in the tibial cartilage. Conclusions The results establish the feasibility of measuring changes on MRI with in situ axial loading. J. Magn. Reson. Imaging 2004;19:317–322. © 2004 Wiley‐Liss, Inc.