Magnetic resonance imaging in the foot and ankle

The first image obtained in a live human with MR was performed in July 1977. It took 4 hours and 45 minutes to produce a single slice. Imaging devices became available routinely in late 1982 and early 1983. Since that time, dramatic technologic growth and improvement has brought MR to the forefront of radiology. It is now believed to be the modality of choice for delineating and staging soft-tissue abnormalities and also shows great promise for evaluating marrow replacing processes. Recently, hyaline cartilage has been identified with MR. Previously in radiology, hyaline cartilage could only be identified when it was outlined by contrast material. Cartilage per se is not a radiographic density. MRI therefore offers potential hope as a cartilage-imaging modality. In addition, the synovium is well delineated with MRI, and it is conceivable that in the future we will use MRI to quantitate synovial proliferation and to monitor response to therapy. The future is quite bright. Currently, spatial resolutions below 1 mm are common with slice thicknesses available at 2 to 2.5 mm. In the future, however, sections will become thinner, spatial resolution will become greater, and localized radiofrequency coils will be developed for specific anatomic regions. Practicing podiatrists should now consider MR a useful tool in the imaging armamentarium.