ESPE Abstracts

Background: The BoneXpert method for automated determination of bone age from hand X-rays has always included a determination of the Bone Health Index (BHI) from the cortical thicknesses in the metacarpals.

Objective and hypotheses: The aim was to extend this so-called digital X-ray radiogrammetry method into adults, and present reference curves for BHI and three other indices: the metacarpal index, the Exton-Smith index and the volume-per-area (proportional to areal BMD).

Method: The reference curves were based on a cross-sectional study of 1662 hand radiographs of healthy subjects of age 9–100 years collected in Jena in 2001–5. We also evaluated a longitudinal study of 116 healthy Danish children born 1952 with on average 11 images taken over the age range 7–40 years.

Results: The Danish BHI data were found to be consistent with the Jena data, and also with the published BHI reference for healthy children. BHI was found to have smaller relative SD than the other three indices in the Jena cohort over the age range 20–80 years.

Conclusion: With this extension, it is possible to follow pediatric patients at risk of poor bone health continuously from childhood into adulthood with exactly the same method. For instance, it can be useful for monitoring treatment effects of GH therapy for transition patients with GH deficiency until ‘peak bone mass’. The relevance of cortical thickness has been shown in this context (1), and the new implementation inside BoneXpert makes this assessment readily available to clinicians. Reference: 1. Hyldstrup L, Conway GS, et al. Growth hormone effects on cortical bone dimensions in young adults with childhood-onset growth hormone deficiency. Osteoporos Int 2012 23 2219–26.