Anterior Chest Wall in Axial Spondyloarthritis: Imaging, Interpretation, and Differential Diagnosis

Anterior chest wall (ACW) inflammation is not an uncommon finding in patients with axial spondyloarthritis (ax-SpA) and reportedly occurs in 26% of these patients. Radiologists may only be familiar with spinal and peripheral joint imaging, possibly due to the inherent challenges of ACW imaging on some cross-sectional imaging modalities. Knowledge of relevant joint anatomy and the location of sites of inflammation allows the interpreting radiologist to better plan appropriate imaging tests and imaging planes. Accurate assessment of disease burden, sometimes in the absence of clinical findings, may alert the treating rheumatologist, allowing a better estimation of disease burden, increased accuracy of potential imaging scoring systems, and optimize assessment and response to treatment. This article reviews salient anatomy and various imaging modalities to optimize diagnosis, important differential diagnoses, and the interpretation of ACW imaging findings in ax-SpA.