Which intervertebral space is essential to see on an L-spine DXA?

• A. Between L2 and L3
• B. Between L3 and L4
• C. Between L4 and L5
• D. Between L5 and S1

Answer: (C)

In a dual-energy X-ray absorptiometry (DXA) scan of the lumbar spine, the intervertebral space between L4 and L5 is essential to visualize. This space is critical because it is commonly included in the region of interest for bone mineral density (BMD) assessments of the lumbar spine. The densitometry measurements aim to evaluate bone health and risk of osteoporosis, particularly in the vertebrae that are at greater risk of fracture.

When performing a DXA scan, the L4-L5 intervertebral space typically provides reliable and reproducible measurements necessary for diagnosing and monitoring conditions such as osteoporosis. This region is often favored due to several factors, including anatomical stability and its position, which tends to reduce variability from surrounding structures or artifacts that might occur in adjacent levels.

The other intervertebral spaces may also be assessed, but L4-L5 is significant for standard BMD evaluations, and findings there contribute meaningfully to a patient's overall bone health assessment. Thus, placing emphasis on this area during DXA imaging is essential for accurate interpretation and clinical decision-making.