[Ankylosing spondylitis--current state of imaging including scoring methods].

Conventional radiography and magnetic resonance imaging (MRI) are currently the most widely used imaging methods for the initial diagnostic evaluation and follow-up of patients with ankylosing spondylitis (AS). Scintigraphy, computed tomography (CT), and positron emission tomography (PET) only play minor roles, although some are being further developed. AS is characterized by inflammatory changes to the sacroiliac joints (SIJs) and spine, as well as asymmetrical arthritis of the peripheral joints and joints near the trunk. The diagnosis of AS is based on clinical parameters and the presence of chronic inflammatory changes to the SIJs on conventional radiographs. Typical radiographic changes also involve the spine. MRI depicts not only chronic changes, but also active inflammatory lesions, which are important for the diagnosis of early disease and precursors of AS. The scoring system of choice for quantifying spinal changes depicted by conventional radiography is the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS). MRI allows the quantitative evaluation of changes involving the SIJs and the spine. Various MRI scoring systems have been proposed to quantify these changes, but they require further validation. This review article presents the imaging modalities used in AS patients, typical findings, and relevant methods of analysis. The most recent developments are discussed.