Evaluation of patient tissue selection methods for deriving equivalent density calibration for femoral bone quantitative CT analyses
Evaluation of patient tissue selection methods for deriving equivalent density calibration for femoral bone quantitative CT analyses
Osteoporosis affects an increasing number of people every year and patient specific finite element analysis of the femur has been proposed to identify patients that could benefit from preventative treatment. The aim of this study was to demonstrate, verify, and validate an objective process for selecting tissues for use as the basis of phantomless calibration to enable patient specific finite element analysis derived hip fracture risk prediction. Retrospective reanalysis of patient computed tomography (CT) scans has the potential to yield insights into more accurate prediction of osteoporotic fracture. Bone mineral density (BMD) specific calibration scans are not typically captured during routine clinical practice. Tissue-based BMD calibration can therefore empower the retrospective study of patient CT scans captured during routine clinical practice. Together the method for selecting tissues as the basis for phantomless calibration coupled with the post-processing steps for deriving a calibration equation using the selected tissues provide an estimation of quantitative equivalent density results derived using calibration phantoms. Patient tissues from a retrospective cohort of 211 patients were evaluated. The best phantomless calibration resulted in a femoral strength (FS) [N] bias of 0.069 ± 0.07% over FS derived from inline calibration and a BMD [kg/cm3] bias of 0.038 ± 0.037% over BMD derived from inline calibration. The phantomless calibration slope for the best method presented was within the range of patient specific calibration curves available for comparison and demonstrated a small bias of 0.028 ± 0.054 HU/(mg/cm3), assuming the Mindways Model 3 BMD inline calibration phantom as the gold standard. The presented method of estimating a calibration equation from tissues showed promise for CT-based femoral fracture analyses of retrospective cohorts without readily available calibration data.
Bone mineral density, Bone strength, Finite element analysis, Hip fractures, Internal tissue calibration, Osteoporosis, Phantomless calibration
115759
Winsor, C
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Li, X
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Qasim, M
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Henak, C R
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Pickhardt, P J
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Ploeg, H
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Viceconti, M
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1 February 2021
Winsor, C
77912bbe-6c67-4af9-9890-637165b6f052
Li, X
0c1123c2-1648-40ba-a5a0-7a39540c1251
Qasim, M
2952cbef-3a52-4fe2-a1a2-c58876c22f91
Henak, C R
359e2b8b-18bb-4e07-88d8-9c55eeb29e17
Pickhardt, P J
e21f657a-b739-40c1-a81e-3510c2718f6c
Ploeg, H
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Viceconti, M
dfd704ca-a3c5-4761-8b13-aee95ea66e0a
Winsor, C, Li, X, Qasim, M, Henak, C R, Pickhardt, P J, Ploeg, H and Viceconti, M
(2021)
Evaluation of patient tissue selection methods for deriving equivalent density calibration for femoral bone quantitative CT analyses.
Bone, 143, , [115759].
(doi:10.1016/j.bone.2020.115759).
Abstract
Osteoporosis affects an increasing number of people every year and patient specific finite element analysis of the femur has been proposed to identify patients that could benefit from preventative treatment. The aim of this study was to demonstrate, verify, and validate an objective process for selecting tissues for use as the basis of phantomless calibration to enable patient specific finite element analysis derived hip fracture risk prediction. Retrospective reanalysis of patient computed tomography (CT) scans has the potential to yield insights into more accurate prediction of osteoporotic fracture. Bone mineral density (BMD) specific calibration scans are not typically captured during routine clinical practice. Tissue-based BMD calibration can therefore empower the retrospective study of patient CT scans captured during routine clinical practice. Together the method for selecting tissues as the basis for phantomless calibration coupled with the post-processing steps for deriving a calibration equation using the selected tissues provide an estimation of quantitative equivalent density results derived using calibration phantoms. Patient tissues from a retrospective cohort of 211 patients were evaluated. The best phantomless calibration resulted in a femoral strength (FS) [N] bias of 0.069 ± 0.07% over FS derived from inline calibration and a BMD [kg/cm3] bias of 0.038 ± 0.037% over BMD derived from inline calibration. The phantomless calibration slope for the best method presented was within the range of patient specific calibration curves available for comparison and demonstrated a small bias of 0.028 ± 0.054 HU/(mg/cm3), assuming the Mindways Model 3 BMD inline calibration phantom as the gold standard. The presented method of estimating a calibration equation from tissues showed promise for CT-based femoral fracture analyses of retrospective cohorts without readily available calibration data.
Text
Evaluation of patient tissue
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More information
Accepted/In Press date: 13 November 2020
e-pub ahead of print date: 17 November 2020
Published date: 1 February 2021
Additional Information:
Funding Information:
The authors would like to thank the Whitaker Foundation for financial support of this project, the Institute for International Education for overseeing the Whitaker International Program Fellowship, and the funding from the European Commission H2020 CompBioMed2 project (Grant agreement ID: 823712 ). This study was funded in part by the EPSRC Frontier Engineering Awards, MultiSim and MultiSim2 projects (Grant Reference Numbers: EP/K03877X/1 and EP/S032940/1 ). Additional thanks go to: Leticia Campello, Ashley Pernsteiner, and Emily Cameron for assistance with repeatability assessments for the phantomless methodology; Bara Kubanova for segmenting patient femurs; Carrie Bartels and Baixuan Yang for assistance capturing CT calibration scans; and Keenan Brown for helpful discussions regarding phantom-based calibration and his experience with GE LightSpeed family CT scanners.
Publisher Copyright:
© 2020
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
Keywords:
Bone mineral density, Bone strength, Finite element analysis, Hip fractures, Internal tissue calibration, Osteoporosis, Phantomless calibration
Identifiers
Local EPrints ID: 446805
URI: http://eprints.soton.ac.uk/id/eprint/446805
ISSN: 8756-3282
PURE UUID: 3c3f3a6d-3645-4621-8f98-9574ebc66ab5
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Date deposited: 23 Feb 2021 17:31
Last modified: 16 Mar 2024 10:48
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Author:
C Winsor
Author:
X Li
Author:
M Qasim
Author:
C R Henak
Author:
P J Pickhardt
Author:
H Ploeg
Author:
M Viceconti
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