The aim of this study was to describe the duplex and color Doppler sonographic findings in active sacroiliitis.
Forty-one joints in 21 patients with active sacroiliitis, 20 sacroiliac joints in 10 patients with osteoarthritis, and 30 sacroiliac joints of 15 asymptomatic volunteers were investigated on duplex and color Doppler sonography. We investigated whether a vessel was present around the posterior portions of sacroiliac joints with color Doppler sonography. When an artery was detected, the resistive index (RI) was measured using duplex Doppler sonography in all groups and also after treatment in the patients with active sacroiliitis.
Vascularization around the posterior portions of sacroiliac joints was seen in 41 joints of the 21 patients with active sacroiliitis, nine joints of six patients with osteoarthritis, and 13 joints of eight volunteers. The mean RI values were 0.62 +/- 0.13, 0.91 +/- 0.09, and 0.97 +/- 0.03, respectively. In the patients with active sacroiliitis, the mean RI value was 0.91 +/- 0.07 after therapy. The RI values for the patients with active sacroiliitis were significantly different from those of the patients with osteoarthritis (p < .001) and of the volunteers (p < .001). In addition, the RI values were significantly different before and after treatment in the patients with active sacroiliitis (p < .001).
Vascularization around the posterior portions of sacroiliac joints increased and RI values decreased in patients with active sacroiliitis. Color and duplex Doppler sonography were able to reveal these changes and can be used in the diagnosis of active sacroiliitis and follow-up after treatment. Thus, RI values may be a quantitative indicator for clinical symptoms in patients with active sacroiliitis.