Vertebral morphometry: repeat scan precision using the Lunar Expert-XL and the Hologic 4500A. A study for the...

Area of Science:

• Osteoporosis Research
• Radiological Imaging
• Clinical Trial Methodology

Background:

• Routine spine radiographs in fracture prevention trials raise radiation safety concerns.
• Vertebral morphometry using dual-energy X-ray absorptiometry (DXA) offers a lower-radiation alternative.
• The precision of low-dose DXA vertebral morphometry needs evaluation for clinical trial use.

Purpose of the Study:

• To assess the short-term inter-scan imprecision of vertebral morphometry.
• To evaluate imprecision due to same-operator, different-day analysis and different-operator analysis.
• To compare the precision of low-dose DXA morphometry with standard radiography.

Main Methods:

• Two DXA morphometry scans were performed on participants (aged ~59) in a hormone replacement therapy trial pilot study.
• Exclusion criteria included osteoporosis (WHO definition) and BMI > 30.9 kg/m².
• Scans assessed vertebrae T7-L4 using Hologic QDR 4500A and Lunar Expert XL equipment.

Main Results:

• Between-scan imprecision was greater than reanalysis imprecision by the same or different operators.
• Measurement uncertainty varied by vertebral level, particularly near the diaphragm and at T7.
• Coefficients of variation for height measurements (1.75–3.40%) were favorable compared to standard radiography (3.1–3.9%).

Conclusions:

• Low-dose DXA vertebral morphometry is preferable to standard radiographs for safety in fracture prevention trials of non-osteoporotic individuals.
• This technique demonstrates good precision, comparable or superior to conventional radiology.
• Conventional radiology may still be necessary for assessing prevalent or incident deformities from non-osteoporotic causes.