Spatially Resolved Transverse Relaxation Times T2of Human Articular Cartilage – an in vitroand in vivoMRI Study

The transverse MR relaxation time T2of articular cartilage could be a helpful parameter for the noninvasive early diagnosis of degenerative joint diseases because it is related to collagen orientation and water content. T2maps were determined for human tibial plateau samples in vitro (5 patients) and for patellar cartilage in vivo (5 volunteers) in a standard whole-body MR scanner operating at a field strength of 1.5 Tesla by means of a multi-spin-echo sequence. A high spatial resolution with pixel sizes between 156 μm (in vitro) and 470 μm (in vivo) was achieved. Cartilage T2maps showed increases from approximately 10 ms at the bone interface to approximately 50 ms at the articular surface. The short-time reproducibility of the mean T2value was approximately 1.4 %. Our results demonstrate that T2maps of articular cartilage can be acquired in vivo with good precision. This method may have potential for noninvasive assessment of material properties of cartilage, e.g. to study degenerative changes with aging and disease.