Cross-calibration of iDXA and pQCT scanners at rural and urban research sites in the Gambia, West Africa
Cross-calibration of iDXA and pQCT scanners at rural and urban research sites in the Gambia, West Africa
Between-scanner differences in measures of bone and body composition can obscure or exaggerate physiological differences in multi-site studies or the magnitude of changes in longitudinal studies. We conducted a cross-calibration study at two bone imaging centres in The Gambia, West Africa where DXA (dual-energy X-ray absorptiometry) and pQCT (peripheral Quantitative-Computed Tomography) are routinely used. Repeat scans were obtained from 64 Gambian adults (58% Male) aged Mean(SD) 30.9 (13.5) years with Mean(SD) body mass index (BMI) 21.7 (4.0) kg/m2, using DXA (GE Lunar iDXA, whole body [WB], total hip [TH], lumbar spine [LS]) and pQCT (Stratec XCT2000L/XCT2000, tibia 4%, 50% sites). Between-scanner differences were tested using paired t tests (p < 0.05). Between-scanner correlation was explored with linear regression, and cross-calibration equations derived. Bland-Altman analysis investigated machine trend/bias. When differences were detected (p < 0.05), cross-calibration equations were applied to urban values, with t tests and Bland Altman analysis repeated. Between-scanner differences exceeded the predefined level of statistical significance (p < 0.05) for WB aBMD and BA; all pQCT measures vBMD, BMC, cortical cross-sectional area (CSA) and stress-strain index (SSI). Between-scanner correlation was high (R2:0.92-0.99), except pQCT Mu.Den (R2 = 0.51). Bland Altman plots indicated bias increased with increasing BMD. Cross-calibration equations attenuated all between-scanner differences and systematic bias. Cross-calibration, particularly of pQCT scanners, is an important consideration in multi-site studies particularly where between population comparisons are intended. Our experiences and findings may be generalisable to other resource-limited settings where the logistics of sourcing parts and in-country repair may result in lengthy scanner downtime.
Body composition, Cross-calibration, DXA, Densitometry, pQCT
573-583
Ó Breasail, Mícheál
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Janha, Ramatoulie
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Zengin, Ayse
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Pearse, Camille
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Jarjou, Landing
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Prentice, Ann
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Ward, Kate A.
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1 May 2023
Ó Breasail, Mícheál
d9d3bc19-e3ca-4e67-90fc-0eec72004164
Janha, Ramatoulie
1a14cb0a-33f3-47f7-8da4-3f7e431d555e
Zengin, Ayse
b2023a08-983d-45bc-ba35-02b5e08aaaa3
Pearse, Camille
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Jarjou, Landing
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Prentice, Ann
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Ward, Kate A.
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Ó Breasail, Mícheál, Janha, Ramatoulie, Zengin, Ayse, Pearse, Camille, Jarjou, Landing, Prentice, Ann and Ward, Kate A.
(2023)
Cross-calibration of iDXA and pQCT scanners at rural and urban research sites in the Gambia, West Africa.
Calcified Tissue International, 112 (5), .
(doi:10.1007/s00223-023-01071-6).
Abstract
Between-scanner differences in measures of bone and body composition can obscure or exaggerate physiological differences in multi-site studies or the magnitude of changes in longitudinal studies. We conducted a cross-calibration study at two bone imaging centres in The Gambia, West Africa where DXA (dual-energy X-ray absorptiometry) and pQCT (peripheral Quantitative-Computed Tomography) are routinely used. Repeat scans were obtained from 64 Gambian adults (58% Male) aged Mean(SD) 30.9 (13.5) years with Mean(SD) body mass index (BMI) 21.7 (4.0) kg/m2, using DXA (GE Lunar iDXA, whole body [WB], total hip [TH], lumbar spine [LS]) and pQCT (Stratec XCT2000L/XCT2000, tibia 4%, 50% sites). Between-scanner differences were tested using paired t tests (p < 0.05). Between-scanner correlation was explored with linear regression, and cross-calibration equations derived. Bland-Altman analysis investigated machine trend/bias. When differences were detected (p < 0.05), cross-calibration equations were applied to urban values, with t tests and Bland Altman analysis repeated. Between-scanner differences exceeded the predefined level of statistical significance (p < 0.05) for WB aBMD and BA; all pQCT measures vBMD, BMC, cortical cross-sectional area (CSA) and stress-strain index (SSI). Between-scanner correlation was high (R2:0.92-0.99), except pQCT Mu.Den (R2 = 0.51). Bland Altman plots indicated bias increased with increasing BMD. Cross-calibration equations attenuated all between-scanner differences and systematic bias. Cross-calibration, particularly of pQCT scanners, is an important consideration in multi-site studies particularly where between population comparisons are intended. Our experiences and findings may be generalisable to other resource-limited settings where the logistics of sourcing parts and in-country repair may result in lengthy scanner downtime.
Text
Cross-calibration of rural and urban Gambian scanners v2 - Copy
- Accepted Manuscript
Text
s00223-023-01071-6
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More information
Accepted/In Press date: 7 February 2023
e-pub ahead of print date: 2 March 2023
Published date: 1 May 2023
Additional Information:
Funding Information:
This research was jointly funded by the MRC (programme codes U105960371, U123261351, MCA760-5QX00) and the Department for International Development (DFID) under the MRC/DFID Concordat agreement. For the purposes of Open Access, the authors (KAW, AP) have applied a Creative Commons Attribution (CC BY) licence to any Author Accepted Manuscript version arising.
Publisher Copyright:
© 2023, The Author(s).
Keywords:
Body composition, Cross-calibration, DXA, Densitometry, pQCT
Identifiers
Local EPrints ID: 476567
URI: http://eprints.soton.ac.uk/id/eprint/476567
ISSN: 0171-967X
PURE UUID: 3e3b19c1-359c-459a-9066-37520ae4202d
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Date deposited: 09 May 2023 16:37
Last modified: 17 Mar 2024 03:40
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Contributors
Author:
Mícheál Ó Breasail
Author:
Ramatoulie Janha
Author:
Ayse Zengin
Author:
Camille Pearse
Author:
Landing Jarjou
Author:
Ann Prentice
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