How to order an X-ray (X-ray) of the sacroiliac (SI) joints?

From the Guidelines

To order an X-ray of the sacroiliac (SI) joints, contact your healthcare provider's office or a radiology facility to request the examination, specifying anteroposterior (AP) views as the first-line imaging method, as recommended by the most recent guidelines 1. When ordering the X-ray, it is essential to include your clinical information and the reason for the examination, such as suspected sacroiliitis, inflammatory arthritis, or trauma. The X-ray procedure is quick and painless, taking only a few minutes, and is useful for detecting structural changes like joint erosion, sclerosis, or fusion that may indicate conditions such as ankylosing spondylitis, sacroiliitis, or arthritis. However, it is crucial to note that X-rays may not detect early inflammatory changes, and advanced imaging like MRI may be necessary for a more accurate diagnosis 1. Some key points to consider when ordering an X-ray of the SI joints include:

• Obtaining a referral or prescription from a healthcare provider, such as a primary care physician, rheumatologist, orthopedist, or pain specialist
• Specifying AP views, as they are the standard projections needed for proper evaluation
• Asking about any preparation instructions, though SI joint X-rays typically don't require special preparation
• Arriving early to complete paperwork, bringing insurance information and referral, and being prepared to remove metal objects from the imaging area
• Considering advanced imaging like MRI if X-rays are negative and sacroiliitis is still suspected, as recommended by the guidelines 1.

From the Research

Ordering X-ray of SI Joints

To order an X-ray of the sacroiliac (SI) joints, the following steps can be considered:

• The decision to order an X-ray should be based on clinical suspicion of sacroiliitis or other conditions affecting the SI joints 2, 3.
• A single AP projection of the pelvis may be sufficient for establishing the presence and severity of sacroiliitis, as it has been shown to have a high agreement rate with detailed oblique radiographs of the SI joints 2.
• However, in some cases, additional views such as oblique or lateral projections may be necessary to fully evaluate the SI joints 2, 3.
• It is essential to consider the patient's symptoms, medical history, and physical examination findings when interpreting the X-ray results 4, 5.
• Other imaging modalities such as MRI or CT may be necessary to confirm the diagnosis or to evaluate the extent of disease, especially in cases where X-ray findings are inconclusive or suspicious 4, 6, 5.

Key Considerations

• The choice of imaging modality depends on the clinical context and the suspected underlying condition 6, 3.
• MRI is particularly useful for visualizing inflammatory and destructive aspects of sacroiliitis and is a crucial element in the diagnosis and classification of axial spondyloarthritis (axSpA) 4, 5.
• X-ray and other imaging modalities should be used in conjunction with clinical evaluation and laboratory tests to establish an accurate diagnosis and develop an effective treatment plan 4, 2, 5, 3.