Publication: Simulated increased soft tissue thickness artefactually decreases trabecular bone score: a phantom study
Issued Date
2016
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eng
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Mahidol University
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BioMed Central
Bibliographic Citation
BMC Musculoskeletal Disorders. Vol. 17, (2016), 17
Suggested Citation
Sasithorn Amnuaywattakorn, Chanika Sritara, Chirawat Utamakul, Wichana Chamroonrat, Arpakorn Kositwattanarerk, Kanungnij Thamnirat, Boonsong Ongphiphadhanakul Simulated increased soft tissue thickness artefactually decreases trabecular bone score: a phantom study. BMC Musculoskeletal Disorders. Vol. 17, (2016), 17. doi:10.1186/s12891-016-0886-1 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/2717
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Title
Simulated increased soft tissue thickness artefactually decreases trabecular bone score: a phantom study
Abstract
Background: Trabecular bone score (TBS), which has been proposed to be used in complementary with bone
mineral density (BMD) to improve the assessment of fracture risk, is negatively associated with body mass index
(BMI). The effect of soft tissue, which is expected to be thicker in subjects with high BMI, on TBS was studied using
three scan types: Hologic with fast array mode (Hfa), Hologic with high definition mode (Hhd), and GE-Lunar iDXA.
Methods: A spine phantom provided by Hologic for routine quality control procedure was scanned using three
scan types: Hfa, Hhd, and iDXA. The phantom was scanned with an overlying soft tissue equivalent material (bolus
used in radiotherapy) of 0 (without), 1, 2.5, 3.5, 5 and 7.5 cm thick. For each setting, 30 acquisitions were performed
in the same way as for the quality control procedure. TBS was calculated using TBS iNsight® software version 2.1 on
the same regions of interest as those used for lumbar spine BMD.
Results: Mean ± SD TBS of the phantom (without overlying soft tissue) were 1.379 ± 0.018, 1.430 ± 0.009, and 1.423
± 0.005 using Hfa, Hhd, and iDXA, respectively. A one-way repeated measures ANOVA showed that there were
statistically differences in TBS due to different thicknesses of soft tissue equivalent materials for all three scan types
(p < 0.001). A Tukey post-hoc test revealed that the decrease in TBS was statistically significant (p < 0.001) when the
soft tissue thickness was 1 cm (−0.0246 ± 0.0044, −0.0319 ± 0.0036, and −0.0552 ± 0.0015 for Hfa, Hhd, and iDXA,
respectively). Although to a lesser degree, the effects were also statistically significant for BMD (p < 0.05): an increase
for Hfa and Hhd but a decrease for iDXA. However, these changes did not exceed the least significant change (LSC)
derived from patients.
Conclusions: Increased soft tissue thickness results in lower TBS value. Although BMD is also affected, it is unlikely
to pose a clinical problem because the change is unlikely to exceed the patient-derived LSC.