1 Rosa, et al: Ultrasound assessment of SIJ Personal non-commercial use only. The Journal of Rheumatology Copyright © 2018. All rights reserved. Value of Color Doppler Ultrasound Assessment of Sacroiliac Joints in Patients with Inflammatory Low Back Pain Javier E. Rosa, Santiago Ruta, Maximiliano Bravo, Luciano Pompermayer, Josefina Marin, Leandro Ferreyra-Garrot, Ricardo García-Mónaco, and Enrique R. Soriano ABSTRACT. Objective. To evaluate the diagnostic value of color Doppler ultrasound (CDUS) for the detection of sacroiliitis, in patients with inflammatory back pain (IBP). Methods. Consecutive patients with IBP and suspected axial spondyloarthritis (SpA), but without a definitive diagnosis, were included. Consecutive patients with defined SpA and axial involvement were included as a control group. All patients underwent clinical evaluation, magnetic resonance imaging (MRI), and CDUS of sacroiliac joints (SIJ) within the same week. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the diagnosis of sacroiliitis by CDUS were calculated, using MRI as the gold standard. Results. There were 198 SIJ evaluated in 99 patients (36 with previous SpA). There were 61 men (61.6%), with a mean age of 39.8 years (SD 11.3) and median disease duration of 24 months (IQR 12–84). At the patient level, CDUS had a sensitivity of 63% (95% CI 48.7–75.7%) and a specificity of 89% (95% CI 76–96%). The PPV was 87.2% (95% CI 72.6–95.7%) and the NPV was 66.7% (95% CI 53.3–78.3%). At joint level, CDUS had a sensitivity of 60% (95% CI 49–70%) and a specificity of 93% (95% CI 88–98%). The PPV was 83% (95% CI 78–95%) and the NPV was 43% (95% CI 33–56%). The sensitivity of CDUS for the diagnosis of axial SpA was 54% (95% CI 36.6–71.2%), specificity was 82% (95% CI 63.1–93.9%), PPV was 79% (95% CI 57.8–92.9%), and NPV was 59% (95% CI 42.1–74.4%). Conclusion. CDUS showed adequate diagnostic properties for detection of sacroiliitis and is a useful tool in patients with IBP. (J Rheumatol First Release December 15 2018; doi:10.3899/jrheum.180550) Key Indexing Terms: INFLAMMATORY BACK PAIN SACROILIITIS SPONDYLOARTHRITIS MAGNETIC RESONANCE IMAGING COLOR DOPPLER ULTRASOUND From the Rheumatology Unit, Internal Medicine Department, and the Radiology Department, Hospital Italiano de Buenos Aires; University Institute Hospital Italiano de Buenos Aires; Fundación Dr. Pedro M. Catoggio para el Progreso de la Reumatología, Buenos Aires, Argentina. This study was supported by an Investigator Initiated Study Grant from UCB. J.E. Rosa, MD, Rheumatology Unit, Internal Medicine Department, Hospital Italiano de Buenos Aires, and University Institute Hospital Italiano de Buenos Aires; S. Ruta, MD, Rheumatology Unit, Internal Medicine Department, Hospital Italiano de Buenos Aires, and University Institute Hospital Italiano de Buenos Aires; M. Bravo, MD, Rheumatology Unit, Internal Medicine Department, Hospital Italiano de Buenos Aires, and University Institute Hospital Italiano de Buenos Aires; L. Pompermayer, MD, Rheumatology Unit, Internal Medicine Department, Hospital Italiano de Buenos Aires, and University Institute Hospital Italiano de Buenos Aires; J. Marin, MD, Rheumatology Unit, Internal Medicine Department, Hospital Italiano de Buenos Aires, and University Institute Hospital Italiano de Buenos Aires; L. Ferreyra-Garrot, MD, Rheumatology Unit, Internal Medicine Department, Hospital Italiano de Buenos Aires, and University Institute Hospital Italiano de Buenos Aires; R. García-Mónaco, MD, Radiology Department, Hospital Italiano de Buenos Aires; E.R. Soriano, PhD, Rheumatology Unit, Internal Medicine Department, Hospital Italiano de Buenos Aires, and University Institute Hospital Italiano de Buenos Aires, and Fundación Dr. Pedro M. Catoggio para el Progreso de la Reumatología. Address correspondence to Dr. J.E. Rosa, Sección Reumatología, Servicio de Clínica Médica, Hospital Italiano de Buenos Aires, Gascón 450, Capital Federal 1181, Buenos Aires, Argentina. E-mail: javier.rosa@hospitalitaliano.org.ar Accepted for publication September 10, 2018. Spondyloarthritis (SpA) represents a set of pathologies that share certain clinical and genetic characteristics, the prototype of which is ankylosing spondylitis (AS). The prevalence of SpA ranges between 0.5 and 1.9% 1 . As with other chronic inflammatory conditions, early diagnosis is essential to prevent irreversible changes and functional disability. The inflammatory involvement of the sacroiliac joints (SIJ), called sacroiliitis, is one of the hallmarks of SpA. The clinical evaluation of SIJ is poorly reproducible and does not allow a safe differentiation between sacroiliitis and mechanical low back pain 2 . The presence of HLA-B27 and the increase of acute-phase reactants (erythrocyte sedimen- tation rate and C-reactive protein) could help the diagnosis of SpA; however, no laboratory tests are pathognomonic of the disease 3 . The radiograph of the SIJ has been traditionally used for the diagnosis, classification, and monitoring of SpA, radiographic sacroiliitis being a central part of the diagnostic www.jrheum.org Downloaded on January 22, 2022 from