Table 2: Summary of patients’ ages at examination two and interval between examinations one and two for patients with no interval changes, minor CT changes within the same scoring grade, progression into sacroiliitis, and progression of already established sacroiliitis. Age and examination interval in years.

No changes between examinationsNew sacroiliitisProgression of sacroiliitisMinor changesAll patients

Median patient age383934.53238
Patient age range19–7229–5821–6627–4519–72
Median interval between examinations35434
Range of interval between examinations<1–211–21<1–16<1–17<1–21