[Imaging of the sacroiliac joints]

The sacroiliac joints (SIJ) are an important part of the axial skeleton and a main area to consider in the examination of back pain both clinically and on imaging. Patients with inflammatory-rheumatic symptoms as well as those with other diagnoses may present with pathological changes in the SIJ even at young ages. Although imaging of the SIJ is not the only factor in approaching the final diagnosis, it nevertheless provides a lot of important information about differential diagnoses, thereby enabling certain causes of back pain to be excluded. Overall, there are four important imaging methods that are being used to evaluate the SIJ in daily routine: conventional radiographs, computed tomography, scintigraphy and magnetic resonance imaging (MRI). In recent years, most of the scientific work on imaging of the SIJs has concentrated on a better understanding of the MRI in this context. This overview article describes the advantages and limitations of the different imaging techniques for the visualization of pathologic changes in the SIJ, also taking into account their value in helping the treating physician to make diagnostic and therapeutic decisions in daily clinical practice.