Multimodal imaging evaluation of the entheses in spondyloarthritis

Multimodal imaging has become an important component in the evaluation of entheses in rheumatology. Clinical examination provides information on local tenderness and symptoms; however, these findings show variable correlation with structural or inflammatory alterations at the enthesis and should thus be complemented by imaging. Within the last decades, the availability, quality and diversity of imaging modalities have increased notably. Ultrasound (US) enables assessment of soft-tissue inflammation, structural abnormalities, and vascularization. Magnetic resonance imaging (MRI) allows visualization of bone marrow and peri-entheseal soft tissues. High-resolution peripheral quantitative computed tomography (HR-pQCT) provides detailed characterization of bone microstructure, while positron emission tomography combined with computed tomography (PET/CT) allows detection of metabolic activity associated with inflammatory processes. Through integration of serological and molecular biomarkers, the multimodal diagnostic approach may ultimately improve diagnostic accuracy.