Beyond Conventional Imaging: Nuclear Imaging in Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a systemic inflammatory disease characterized primarily by symmetrical small joint inflammation and damage, often accompanied by anti-cyclic citrullinated peptide (ACPA) and rheumatoid factor (RF) positivity. While conventional imaging modalities such as plain radiographs, ultrasound (US), and magnetic resonance imaging (MRI) are widely used to assess articular and some extra-articular manifestations, each presents limitations in terms of accessibility, comprehensiveness, and diagnostic scope. Nuclear imaging techniques, including positron emission tomography (PET), scintigraphy, and single-photon emission computed tomography (SPECT), offer whole-body imaging capabilities and the potential to simultaneously detect multi-system involvement, making them uniquely suited to the complex, systemic nature of RA. This review explores the current and potential roles of nuclear imaging in RA, highlighting its advantages in detecting both articular and extra-articular disease and its emerging promise as a routine tool in RA management.