EVALUATION OF SACROILIAC JOINTS IN ANKYLOSING-SPONDYLITIS BY CONVENTIONAL RADIOGRAPHY, COMPUTED-TOMOGRAPHY AND QUANTITATIVE SCINTIGRAPHY

Sacroiliac joints of 30 patients clinically diagnosed as ankylosing sp ondylitis were investigated by suprapubic sacroiliac radiography (SRR) , sacroiliac computed tomography (SCT) and quantitative sacroiliac sci ntigraphy (QSS) and these methods were compared. In the case of diagno sing definite sacroiliitis, SSR was positive in 23 patients (76.6%), S CT in 25 patients (83.3%) and QSS in 17 patients (56.6%). Although the re was no significant difference between SSR and SCT in the case of gr ading sacroiliitis, the number of normal patients was 7 with SSR and 3 with SCT. When grading was done by taking CT as standard, mean SI ind ex values with QSS were in the normal range in grades 0, 1 and 4. In g rades 2 and 3, SI index values showed sacroiliitis as compared with gr ade 4. Therefore, if plain radiography is normal or doubtful in patien ts clinically fitting ankylosing spondylitis, computed tomography must be the choice of investigation. On the other hand, QSS is effective i n showing activation of inflammation quantitatively instead of diagnos ing sacroiliitis. Thus it is useful in following physiopathological ch anges.