MR-IMAGING OPTIMIZATION OF THE ARTICULAR HIP CARTILAGE BY USING A T-1-WEIGHTED 3-DIMENSIONAL GRADIENT-ECHO SEQUENCE AND THE APPLICATION OF A HIP-JOINT TRACTION

Purpose: The Purpose of this study was to examine the accuracy of MR-I maging of the healthy and the arthrotically altered articular hip cart ilage with in vivo and in vitro separation of femoral head cartilage a nd acetabular cartilage.Material and methods: Images of three animal c adaver hips, 8 dissected patient femoral heads and 18 hip joints of hu man corpses, all either with arthrosis stage I-III or artificial carti lage defects, were compared with their corresponding anatomic sections , Additional histomorphologic examinations of the arthrotic cartilages were conducted, and MR-Imaging of 20 healthy and 21 arthrotic patient hips was performed using a specific traction method. Results: Using a T-1-weighted 3-dimensional gradient-echo sequence and a traction of t he hip joint, it was possible due to the low-signal imaging of the joi nt space to separate in vivo the high-signal femoral head cartilage fr om the high-signal acetabular cartilage, In horizontal position of the phase-encoding parameter, minimisation of the chemical-shift artifact , mainly in the ventro-lateral areas, was accomplished. MRI measuremen ts of the articular cartilage widths showed significant correlations ( p<0.001) with the corresponding anatomic sections. At the same time th e T-1 3-dimensional gradient-echo sequence of the lateral femoral head with r=0.94 showed the lowest deviations of the measurements. It was possible with MR-Imaging to distinguish four cartilage qualitites. Con clusions: Using these MR-examinations, an improved imaging of early st age arthrotic cartilage defects is possible, and the status of the art hrotic hip cartilage with regard to intertrochanteric osteotomy can al so be assessed.