Introduction: Spondyloarthropathies including ankylosing spondylitis (AS) require early diagnosis to prevent irreversible changes. Sacroiliitis is a common initial manifestation of AS and is frequently diagnosed by magnetic resonance imaging (MRI). The goal of our study was to assess color Doppler ultrasonography as a potential diagnostic tool in suspected sacroiliitis in comparison with MRI representing the gold standard.
Materials and methods: Fifty-one consecutive patients with AS and sacroiliitis and 30 control subjects underwent contrast-enhanced MRI and high resolution color Doppler and duplex ultrasonography of both sacroiliac joints (SIJ) for the detection of vascularization and blood flow spectral Doppler waveform analysis.
Results: MRI demonstrated active disease in 27 and inactive disease in 24 patients. CDUS detected pulsatile monophasic wave spectral waveform flow in 22 patients with the active disease, and triphasic in 7 patients with inactive disease and in 8 control patients. The sensitivity, specificity, positive predictive value and negative predictive value for active sacroiliitis detection with CDUS were 82 % (95 % CI, 68-91 %), 92 % (95 % CI, 85-96 %), 91 % (95 % CI, 84-96 %), and 84 % (95 % CI, 70-92 %), respectively, for pulsatile monophasic wave spectral waveform Doppler sonography. MRI of SIJ was negative in all 30 (60 SIJ) control participants.
Conclusions: Our results show that CDUS is a practical and useful tool in the diagnosis of active sacroiliitis.