1. A method for the analysis of three dimensional image data representing an articular cartilage to extract a quantitative parameter indicative of joint pathology, which method comprises determining from the data a measure representative of cartilage homogeneity, and further comprising comparing the measured value for the joint with measured values previously established in respect of healthy joints and/or in respect of joints characterised by a pathology, wherein said measure representative of cartilage homogeneity is the entropy, the mean, the standard deviation or the uniformity of measured intensities within a region of interest of the image.