CPT Code for DXA Study of the Hips in a Patient on Estrogen Replacement Therapy
The correct CPT code for a dual-energy X-ray absorptiometry (DXA) study of the hips in a patient on estrogen replacement therapy is 77080.
Rationale for CPT Code Selection
According to the American College of Radiology (ACR) Appropriateness Criteria, DXA of the lumbar spine and hip(s) is rated as "usually appropriate" (9/9) for bone mineral density (BMD) assessment in patients with risk factors, including those on hormone replacement therapy 1.
Understanding the CPT Code Options:
- 77080: DXA bone density study of axial skeleton (hips, pelvis, spine)
- 77077: DXA bone density study, limited (peripheral skeleton, e.g., radius, wrist, heel)
- 77078: CT bone density study, axial skeleton
- 77081: DXA bone density study, peripheral skeleton
Clinical Indications for DXA in Patients on Estrogen Therapy
Patients on estrogen replacement therapy are at risk for changes in bone mineral density, making them appropriate candidates for DXA scanning. The European Journal of Nuclear Medicine and Molecular Imaging guidelines highlight that:
- Hormone replacement therapy affects bone mineral density and is considered a risk factor that warrants monitoring 1
- DXA of the hip is particularly important as it provides valuable information about fracture risk 1
Proper Technique and Considerations
When performing DXA studies of the hip in patients on estrogen replacement therapy:
- Patient positioning is critical - the femur should be properly rotated with the lesser trochanter not visible 1
- Artifacts that may affect hip DXA measurements include:
- Hip osteoarthritis
- Prior history of osteosynthesis hardware
- Incorrect ROI positioning
- Improper rotation of the femur 1
Common Pitfalls to Avoid
Incorrect patient preparation: Patients should remove metal objects but can remain clothed in non-reflective materials 1
Improper site selection: In cases where one hip has artifacts or abnormalities, the contralateral hip should be used 1
Failure to recognize artifacts: Hip osteoarthritis can cause cortical bone thickening, resulting in falsely elevated BMD values 1
Incorrect code selection: Using peripheral DXA codes (77077,77081) when axial skeleton imaging is performed will result in improper billing
Follow-up Recommendations
For patients on estrogen replacement therapy:
- Follow-up DXA scans are typically recommended at 1-2 year intervals to monitor treatment effectiveness 1
- The same anatomical site and preferably the same DXA machine should be used for follow-up studies to ensure consistency in measurements
In conclusion, for a patient on estrogen replacement therapy receiving a DXA study of the hips, the appropriate CPT code is 77080, which represents a bone density study of the axial skeleton.