CT of the sacroiliac joints shows these paired joints between the sacrum and the iliac bones of the pelvis, and the bones that form them. It is used when an X-ray is not enough, for example at early stages or with subtle changes.
- Duration5 min
- Contrastusually not needed
- Preparationnone
- Report30 min – 1 hour
What it shows
- Fractures and cracks of the sacrum and pelvic bones next to the joint surfaces
- Multiple and complex pelvic fractures
- Sacroiliitis, including in ankylosing spondylitis and psoriatic arthritis
- Developmental anomalies of the joint
- Tumours in the joint area
- Haematomas of the surrounding tissues
When it is recommended
- Pain, crunching or discomfort in the sacroiliac joint area
- Pelvic injury
- Suspected sacroiliitis in rheumatic diseases
- X-ray that has not given enough information
Good to know
- MRI shows cartilage, the joint capsule and ligaments better, so it is often chosen first for early sacroiliitis; CT is best for bone injury.
General information about CT — safety, contraindications, contrast and what to expect — is on the CT page.