Tomosynthesis of the thoracic spine: added value in diagnosing vertebral fractures in the elderly

Objectives: Thoracic spine radiography becomes more difficult with age. Tomosynthesis is a low-dose tomographic extension of radiography which may facilitate thoracic spine evaluation. This study assessed the added value of tomosynthesis in imaging of the thoracic spine in the elderly. Methods: Four observers compared the image quality of 50 consecutive thoracic spine radiography and tomosynthesis data sets from 48 patients (median age 67 years, range 55–92 years) on a number of image quality criteria. Observer variation was determined by free-marginal multirater kappa. The conversion factor and effective dose were determined from the dose–area product values. Results: For all observers significantly more vertebrae were seen with tomosynthesis than with radiography (mean 12.4/9.3, P <0.001) as well as significantly more fractures (mean 0.9/0.7, P = 0.017). The image quality score for tomosynthesis was significantly higher than for radiography, for all evaluated structures. Tomosynthesis took longer to evaluate than radiography. Despite this, all observers scored a clear preference for tomosynthesis. Observer agreement was substantial (mean κ = 0.73, range 0.51–0.94). The calibration or conversion factor was 0.11 mSv/(Gy cm²) for the combined examination. The resulting effective dose was 0.87 mSv. Conclusion: Tomosynthesis can increase the detection rate of thoracic vertebral fractures in the elderly, at low added radiation dose. Key Points: • Tomosynthesis helps evaluate the thoracic spine in the elderly.• Observer agreement for thoracic spine tomosynthesis was substantial (mean κ = 0.73).• Significantly more vertebrae and significantly more fractures were seen with tomosynthesis.• Tomosynthesis took longer to evaluate than radiography.• There was a clear preference among all observers for tomosynthesis over radiography.