New York criteria for radiological grading of sacroiliitis

Devised in 1966, it was modified in 1984 to enable the diagnosis of ankylosing spondylitis. To date, it is the most used classification in radiography. Studies have shown that, it could take up to 9 years after disease onset for radiographic changes to appear. MRI is a no brainer in picking up disease way before a radiograph.

Stage 0

No abnormality in either sacroiliac joint on a radiograph

Stage 1

Suspicion of abnormality (blurring of joint margins)

Stage 2

Minimal abnormalities (solitary erosons, small juxta articular sclerosis of iliac or sacral areas)

Stage 3

Extensive erosions, juxta articular sclerosis, multiple erosions and widening of joint, partial ankylosis

Stage 4

Complete ankylosis

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1. Sudoł-Szopińska I, Kwiatkowska B, Włodkowska-Korytkowska M, Matuszewska G, Grochowska E. Diagnostics of Sacroiliitis According to ASAS Criteria: A Comparative Evaluation of Conventional Radiographs and MRI in Patients with a Clinical Suspicion of Spondyloarthropathy. Preliminary Results. (2015) Polish journal of radiology. 80: 266-76.