Redefining Osteoarthritis Through Imaging: from Magnetic Resonance Imaging to Genicular Artery Embolization

Abstract

Osteoarthritis is traditionally perceived as a disease of "wear and tear", often diagnosed through radiographic findings such as joint space narrowing and osteophyte formation. However, this structural approach often delays diagnosis until irreversible joint damage occurs. Contemporary understanding of OA now recognizes it as a biologically active process involving synovitis, neovascularization, cartilage degeneration, and subchondral bone remodeling. This shift demands a redefinition of diagnostic and therapeutic strategies, with radiology playing a central role in both. Objectives to review the evolving role of advanced imaging modalities in osteoarthritis (OA), including Magnetic Resonance Imaging (MRI), Ultrasonography (US), and Computed Tomography (CT), and to evaluate the emerging therapeutic role of Genicular Artery Embolization (GAE) as an image-guided, non-surgical option for knee OA. MRI allows early detection of bone marrow edema, cartilage softening, and synovial inflammation. Advanced techniques such as T2 mapping, T1ρ, and delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) provide quantitative evaluation of cartilage integrity. US enables dynamic, bedside assessment of synovial hypertrophy and vascularity, particularly using Doppler imaging, making it valuable for monitoring active inflammation. Dual-energy CT enhances visualization of subchondral bone changes and urate deposition. These modalities also support patient selection and post-procedural monitoring for GAE, a minimally invasive, image-guided intervention that targets abnormal periarticular neovessels to alleviate pain and inflammation. GAE has shown promising results in patients with moderate knee OA, particularly those who are not candidates for surgery. Modern imaging does more than confirm osteoarthritis; it reveals its pathophysiology, progression, and therapeutic targets. Radiologists are no longer passive observers, but active contributors to OA care. By integrating MRI, US, CT, and interventional radiology techniques such as GAE, radiology is reshaping both diagnosis and treatment in this era of robust technology and multidisciplinary excellence.