What X-ray (XR) should I consider for a new finding of scoliosis?

Radiographic Evaluation for New Finding of Scoliosis

For a new finding of scoliosis, standing posteroanterior (PA) and lateral radiographs of the complete spine should be obtained as the initial imaging evaluation. 1, 2

Initial Radiographic Assessment

Primary Radiographic Protocol:

• Standing PA radiograph (preferred over AP to reduce breast radiation exposure)
• Standing lateral radiograph of the complete spine
• Images should include the entire spine from cervical to lumbar regions and visualize the iliac crests (for Risser staging)

Key Measurements to Obtain:

• Cobb angle measurement (angle ≥10° defines scoliosis) 3
• Assessment of vertebral rotation using Nash-Moe method 4
• Risser index (degree of iliac apophysis ossification) to assess skeletal maturity 1
• Evaluation for congenital vertebral anomalies

Follow-Up Imaging Considerations

The frequency of follow-up radiographs depends on patient factors:

• High risk for progression (Risser stages 0-3, curves >20°): Consider radiographs every 6-12 months 2
• Lower risk (Risser stages 4-5): Radiographs every 18 months 2
• Documented progression: More frequent monitoring may be needed

Advanced Imaging Indications

MRI of the complete spine is indicated when:

• Congenital scoliosis is identified on radiographs
• Neurological abnormalities are present on examination
• Atypical curve patterns are observed
• Patient reports back pain
• Patient is under 10 years of age with significant curve
• Rapid progression of curve is documented

Technical Considerations

• Use lower-dose radiography techniques (digital radiography preferred over conventional film) 1
• Biplanar slot scanners may be used if available to further reduce radiation exposure 1
• Consider EOS imaging system for follow-up if available (provides 3D information with lower radiation dose) 5

Common Pitfalls to Avoid

1. Inadequate imaging: Ensure radiographs include the entire spine and iliac crests
2. Improper positioning: Patient must be standing for accurate curve assessment
3. Overlooking non-idiopathic causes: Carefully evaluate for congenital anomalies, especially in children under 10 years
4. Excessive radiation: Limit follow-up radiographs to clinically necessary intervals
5. Underestimating the true curve: The projected Cobb angle on PA radiographs often underestimates the true three-dimensional curve magnitude 4

Patient Referral Guidelines

Refer to a spine specialist if:

• Curve is >10° in a patient younger than 10 years
• Curve is >20° in a patient 10 years or older
• Atypical features are present
• Back pain or neurological abnormalities are associated with the curve 6

The American College of Radiology and Society on Scoliosis Orthopedic and Rehabilitation Treatment (SOSORT) guidelines emphasize the importance of minimizing radiation exposure while obtaining adequate diagnostic information for proper management of scoliosis 1.