Bone Abstracts

Purpose: Children have greater lifetime risks of radiation-induced complications compared to adults. In children with osteogenesis imperfecta conventional radiographs are obtained to assess spine morphometry, while DXA assesses bone density. In adults DXA is now used for both. We aim to establish whether iDXA can replace spine radiographs in the assessment of paediatric vertebral morphometry.

Methods: An 18-month prospective recruitment of 200 consented children with, and 50 without suspected reduction in bone density, aged 5–15 years, will have lateral spine radiographs and lateral DXA scans on the same day. Three observers will independently assess all images (blinded to corresponding results of radiographs and DXA) using a modified ABQ technique. 100 random images will be interpreted twice. Diagnostic accuracy and inter and intra-observer reliability of DXA will be compared to the gold standard of radiography.

Patient/carer experience, radiation dose of DXA compared to radiographs and health economics will be assessed.

Results: Interim results of the first 50 recruited patients showed 26 had 1 or more vertebral fractures. The fracture detection sensitivity for DXA was 62.7% and specificity 87.8%. The overall accuracy for vertebral fracture detection with DXA was 83.5%. The overall agreement between radiographs and DXA was 68.7%.

Conclusion: Using the ABQ technique in children has limitations and a more reliable scoring system is required. Compared to radiography DXA does not appear to be worse for morphometry and given the reduced dose and comparable CEC qualities, DXA should be recommended for morphometry in children after more robust analyses.