[New imaging techniques in the evaluation of joint cartilage]

Magnetic resonance (MR) imaging provides an excellent spatial resolution to visualize cartilage and define its main properties. Both 1.5 and especially 3 Tesla equipments have become very efficient in showing the whole articular cartilage and classifying the degenerative damage by analyzing morphological, structural and physical properties. MR evaluation of articular cartilage is of great clinical importance due to the prevalence of degenerative lesions and the development of new drugs and surgery-based treatments. In this work we explain the advances in the MR quantitation of the articular cartilage properties, particularly focusing on T2 and T1 relaxation times, the distribution of first-pass contrast agent (pharmacokinetic study) and late enhancement percentage. By using specific sequences and adequate measuring techniques, MR allows the evaluation of important parameters such as cartilage surface, thickness and volume; signal intensity and the physical properties related to collagen integrity and edema; cartilage perfusion and endothelial permeability related to neovascularization; and the presence of late enhancement areas, related to proteoglycan concentrations. This information will aid early diagnosis, establishment of the degree of degeneration, assessment of prognosis, definition of therapeutic options and evaluation of treatment effectiveness. The study of the cartilage structural and functional alterations by MR imaging is an excellent biomarker of tissue degeneration.