Diagnosis of inflammatory sacroiliitis. Comparison of complementary examinations

: In order to test the sensitivity of different techniques in the diagnosis of sacroiliitis, we have made a prospective and non-controlled study of 22 patients using standard radiography of the sacroiliac joint; conventional tomography and axial scintigraphy (calculation of an ISI sacroiliac index). The normal upper limit of the sacroiliac index (1.42) was studied in parallel, using a group of 63 control subjects. Correlation between the radiological examinations was average, but was very poor between radiology and scintigraphy. Conventional tomography and calculation of the sacroiliac index were of equal value diagnostically. Clear images of juxta-articular geodes were seen during scanning, but were not taken into account in the diagnosis. They may represent the onset of larger erosions and need to be verified.