Dual‑Energy CT in Inflammatory Arthritis: A Comprehensive Review

Inflammatory arthritis and crystal-associated arthropathies frequently present with overlapping clinical features, creating diagnostic and phenotypic challenges when conventional imaging findings are inconclusive. Dual-energy computed tomography (DECT) extends standard CT by enabling material-specific characterization, allowing differentiation of monosodium urate and calcium-containing deposits, and supporting selected applications beyond crystal detection. This narrative review synthesizes evidence from a curated set of PubMed-indexed studies to examine DECT principles, workflow considerations, interpretation pitfalls, and clinical utility across gout, calcium pyrophosphate deposition disease (CPPD), rheumatoid arthritis (RA), psoriatic arthritis (PsA), axial spondyloarthritis (axSpA), and osteoarthritis (OA). The focus is practical and clinically oriented, emphasizing qualitative evidence synthesis rather than quantitative pooling. DECT has its most established and evidence-supported role in gout, where it provides non-invasive crystal detection, burden mapping, and therapy monitoring. In CPPD, it functions primarily as a problem-solving adjunct when radiographs or ultrasound is inconclusive. In RA and PsA, applications such as iodine overlay imaging and virtual non-calcium reconstruction remain adjunctive and exploratory, with magnetic resonance imaging continuing as the reference standard for inflammatory assessment. In axSpA, DECT strengthens structural staging and may offer selective adjunct marrow evaluation, while in OA, its use is limited to targeted phenotyping in suspected crystal-overlap scenarios. Overall, DECT delivers the greatest clinical value when applied in a disease-specific, question-driven manner within multimodality imaging pathways and interpreted with attention to standardized protocols and potential artifacts.