Frequency of potential causes of lower back pain and incidental findings in patients with suspected sacroiliitis: retrospective analysis of 886 patients with negative sacroiliac MRI examination for sacroiliitis.

In patients with suspected SI but negative MRI examinations for SI, some other possible causes for lower back pain and several incidental findings can be seen on imaging. The presence of these findings may explain the patient's symptoms, and awareness of these conditions may be helpful in patient management and individualizing treatment.