ORIGINAL ARTICLE Metabolic disturbances identified by SPECT-CT in patients with a clinical diagnosis of sacroiliac joint incompetence

Purpose To establish the sensitivity and specificity of cross-sectional scintigraphy [single photon emission com-puted tomography (SPECT)] combined with computed X-ray tomography (CT) in the detection of sacroiliac joint (SIJ) mechanical dysfunction and evaluate reproducibility of reporting. Methods Patients with pelvic girdle pain either on the basis of peri-partum SIJ dysfunction or trauma were included. These patients were imaged with bone scintig-raphy with hybrid imaging with SPECT/CT. Results The study group comprised 100 patients (72 females, 28 males). Trauma accounted for 52 % and the remainder were patients with peri-partum pain. Average age was 43 years and average length of history was [2 years. The major finding was increased uptake in the upper SIJ and posterior soft-tissues/ligaments. Hybrid imaging had a sensitivity of 95 % and specificity of 99 %. Positive predictive value was 99 % and negative predictive value 94 %. Power of the test was 1.0. Reproducibility of the test was good with kappa values of 0.85. Conclusion Hybrid imaging with SPECT/CT reproduc-ibly demonstrates metabolic alterations around the SIJ in patients with SIJ dysfunction, which we have termed SIJ incompetence. The condition is more common than pre-viously recognised and frequently occurs after trauma, which has not been reported previously