[Clinical use of magnification radiography in rheumatologic differential diagnosis]

Rheumatologic joint disorders were examined with high-definition microfocal magnification radiography. The magnification technique was compared to conventional radiographs (mammographic film-screen combinations). The microfocal x-ray unit had a spot size of 20-130 microns. Fourty patients with early arthritis (history of less than 18 months) were examined; x5 magnification was used. Digital luminescence radiography was employed to minimize radiation dose. Digital image processing included simulation of conventional technique and edge enhancement. Magnification radiographs and conventional technique were evaluated. In 20/40 patients articular lesions were detected. Magnification radiography gave additional information in 14/20 patients: in 5/14 patients lesions were seen only with magnification radiography (erosions n = 3, loss of the cortical white line n = 2), in 9/14 patients the extent of the lesions could be evaluated better. Hence, magnification radiography proved a valuable mean in early diagnosing and evaluating rheumatic disease.