How to Order Combined Lumbar Spine and Hip CT
Order these as two separate studies: "CT Lumbar Spine without IV contrast" and "CT Hip without IV contrast" - both can be performed in a single scanning session by specifying the anatomic coverage needed.
Practical Ordering Approach
When you need imaging of both regions, the most efficient approach is to:
- Write two distinct orders or specify both anatomic regions on a single requisition if your system allows
- Use the terminology: "CT Lumbar Spine without IV contrast" AND "CT Hip without IV contrast"
- Indicate to radiology that these can be performed as a continuous acquisition to minimize repositioning and radiation exposure
- Specify the exact coverage needed (e.g., "L1-S1" for lumbar spine and "bilateral hips including acetabulum and proximal femur")
Clinical Context Matters
The appropriateness of ordering both studies depends on your clinical scenario:
For Lumbar Spine CT 1:
- Usually appropriate for low back pain with trauma, osteoporosis, elderly patients, or chronic steroid use
- Can be complementary with radiographs in these settings
- Consider MRI instead if evaluating for infection, cancer, or surgical planning (unless contraindicated)
For Hip CT 2:
- Usually appropriate after negative or indeterminate radiographs when occult hip fracture is suspected
- CT has 94% sensitivity and 100% specificity for radiographically occult hip fractures 2
- Particularly valuable for rapid diagnosis in trauma settings
Important Caveats
Radiation considerations: Combined lumbar spine and hip CT delivers significant radiation exposure. Lumbar spine CT alone carries an estimated cancer risk of approximately 1 in 3,200, with whole lumbar spine effective dose around 6-7 mSv 3. Adding hip imaging increases this burden.
Hip-spine syndrome: Be aware that hip and lumbar spine pathology frequently coexist and can produce overlapping symptoms (low back pain, buttock pain, groin pain, thigh pain) 4, 5. If you're ordering both studies, you're likely dealing with this diagnostic challenge - ensure you're addressing the primary pain generator first.
Consider MRI instead: If there's no contraindication and trauma is not the primary concern, MRI of both regions may provide superior soft tissue detail without radiation exposure, particularly for evaluating degenerative disease, infection, or malignancy 1.
Communication with Radiology
Specify on your requisition:
- Clinical indication for each region
- Whether studies can be performed as continuous acquisition
- Any specific anatomic landmarks or coverage requirements
- Urgency (trauma vs. non-urgent evaluation)
This approach minimizes patient repositioning, optimizes radiation dose through continuous scanning protocols, and ensures both anatomic regions are adequately evaluated 6.