Assessing the Effect of in-vitro Soft Tissue Thickness on Bone Mineral Density Using Dual-Energy X-ray Absorptiometry

Bone mineral density (BMD) assessment by using dual-energy X-ray absorptiometry (DXA) plays an important role in diagnosis and treatment of osteoporosis. Variation in soft tissue thickness may cause probability errors in DXA bone values. The aim of this study was to assess the effect of soft tissue thickness on bone mineral.
A spine phantom consisting of bone and soft tissue equivalents (Aluminum and Perspex respectively) was made to simulate different status of bone (normal, osteopenia and osteoporosis) and abdominal thicknesses. BMD measurements were performed by DXA using a Norland XR-46 on 45 patients. The statistical analysis for determining the BMD, bone mineral content (BMC), bone area (BA) measurements was done using SPSS software.
Findings: According to Pearson correlation test, variation of soft tissue thickness had no statistically significant relation on BMD, BMC and BA (P > 0.05). But non-parametric regression determined soft tissue thickness had some effect on BMD and BMC (P 0.05).
Variation of soft tissue thickness had no considerable effect (less than1%) on bone mineral results, so errors arising from soft tissue thickness in DXA are negligible