Advances in the radiological assessment of rheumatoid arthritis.

Standard radiographic assessment of changes in rheumatoid joints is limited by factors within the radiographic process, i.e. the performance of the X-ray equipment, recording medium and X-ray assessment. The development of microfocal X-ray units overcomes many of the limitations of conventional radiology. The radiographs of high magnification and resolution produced by this system permit early diagnosis and direct quantitative evaluation of disease progress, providing a more effective assessment in therapeutic trials. Advances in other imaging techniques such as computed tomography (CT), nuclear magnetic resonance (NMR) and emission tomography are evaluated in terms of their potential value in assessing disease activity.