ESPE Abstracts

Background: Vertebral fractures (VF) are recognised as an important aspect of bone health in children and adolescents, yet most of them are not clinically apparent. The clinical utility of vertebral fracture assessment (VFA) using dual-energy X-ray absorptiometry (DXA) for vertebral morphometry has not been evaluated in the paediatric population.

Method: VFA was performed independently by two non-radiologist observers in 110 patients (52M/58F) as part of their investigation for low bone mineral density. The median age of the patients was 13.6 years (3.6,19.2). Lateral DXA images of the spine from T6 to L4 were obtained using Lunar Prodigy DXA device. The diagnosis of VF was performed according to the extent of the difference in height ratios from 100% using Genant Semi-quantitative Method.

Results: Interobserver agreement in vertebral readability was 95% (κ,0.78). The vertebral bodies not readable by both observers were 210/1210 (17%) and 174 (83%) were located from T6 through T8. Conversely, 844/880 (96%) of vertebral bodies from T9 through L4 were adequately visualized (P<0.0001). Among the visualized vertebrae by both observers, 47 (4.7%) in 31 (28%) patients and 57 (5.7%) in 34 (31%) patients were classified as VF by observer 1 and by observer 2 respectively. Both observers detected a total of 46VF in 28 (26%) patients and 13 (28%) of them were classified as moderate or severe. The anatomical distribution of VF was biphasic with peaks located on T9(odds ratio, 2.1(1.2, 4.4)) and L4 (odds ratio, 1.7(1.0, 3.6)). Interobserver per-vertebra agreement for the presence of a fracture was 98.8%(κ, 0.88) and for the grade of the fracture was 98%(κ, 0.76). Interobserver per-patient agreement for the presence of a fracture was 92%(κ, 0.8).

Conclusion: VFA with DXA reach an excellent level of agreement between observers in identifying reduction of vertebral heights in paediatric population. The readability of vertebral bodies from T6 to T8 is suboptimal and interpretation at this level should be exercised with caution.