Magnetic Resonance Imaging in Peripheral Spondyloarthritis

Abstract Peripheral spondyloarthritis is diagnostically challenging due to its vague symptoms, such as joint pain or swelling, which are often mistaken for mechanical injuries or osteoarthritis. It is a seronegative condition with no definitive blood test, and diagnosis relies on clinical features such as dactylitis or human leukocyte antigen-B 27 positivity, which may not always be present. Imaging can also be challenging, as early radiographs are often normal, and magnetic resonance imaging (MRI) findings, such as entheseal bone marrow edema, are frequently misdiagnosed as nonspecific changes or bone bruises. Without clear extra-articular features such as psoriasis, the inflammatory nature of the disease may be overlooked, leading to delays in diagnosis and unnecessary treatments. Early diagnosis is essential to prevent long-term disability. This case series of six patients highlights the role of MRI in diagnosing this challenging condition.