[Value of direct radiographic enlargement (DIMA) in early detection of rheumatic inflammatory lesions. Comparative evaluation with high resolution conventional imaging technique].

Rheumatological joint disorders were examined with mammographic film-screen combinations and high-definition microfocal magnification radiography. Our objective was to evaluate the potentials of magnification radiography in diagnosing arthritis by means of interobserver and ROC analysis. The microfocal X-ray unit had a spot size of 20-130 microns; 5-fold magnification was performed. Digital luminescence radiography was employed; digital image processing included simulation of conventional technique and edge enhancement. Eighty radiographs were obtained with conventional and magnification technique. All films were analyzed by five readers. Anatomical and pathological structures were evaluated. The percentage of uncertain findings in magnification radiography was lower compared to conventional radiographs (14% to 26%); in 8% (compared to 19%) the diagnosis of erosions was uncertain. Additionally ROC analysis was carried out. Magnification radiography was significantly (p < 0.03) better than the conventional films.