Abstract: An orthopedic magnetic resonance imaging system is disclosed. This system includes a source of magnetic resonance imaging data sets resulting from successive magnetic resonance imaging acquisitions from a diseased joint of a patient. A segmentation module segments surfaces in the joint based on information contained within at least one of the data sets, and a registration module spatially registers, in three dimensions, information represented by a first of the data sets with respect to information represented by one or more further data sets for the same patient. A comparison module detects differences between information represented by the data sets caused by progression of the disease in the joint of the patient between acquisitions. A cross-patient comparison module can compare detected differences for the patient with detected differences for at least one other patient.