Abstract
Introduction
Quantitative computed tomography (QCT) can supplement dual x-ray absorptiometry by
enabling geometric and compartmental bone assessments. Whole-body spiral CT scanners
are widely available and require a short scanning time of seconds, in contrast to
peripheral QCT scanners, which require several minutes of scanning time. This study
designed and evaluated the accuracy and precision of a homemade QCT calibration phantom
using a whole-body spiral CT scanner.
Materials and Methods
The QCT calibration phantom consisted of K2HPO4 solutions as reference. The reference material with various concentrations of 0,
50, 100, 200, 400, 1000, and 1200 mg/cc of K2HPO4 in water were used. For designing the phantom, we used the ABAQUS software.
Results
The phantoms were used for performance assessment of QCT method through measurement
of accuracy and precision errors, which were generally less than 5.1% for different
concentrations. The correlation between CT numbers and concentration were close to
one (R2 = 0.99).
Discussion
Because whole-body spiral CT scanners allow central bone densitometry, evaluating
the accuracy and precision for the easy to use calibration phantom may improve the
QCT bone densitometry test.
Conclusion
This study provides practical directions for applying a homemade calibration phantom
for bone mineral density quantification in QCT technique.
Résumé
Introduction
La tomodensitométrie quantitative (QCT) peut servir de complément à la DXA en facilitant
les évaluations géométriques et des compartiments des os. Les tomodensitomètres hélicoïdaux
pour corps entier sont largement accessibles et sont rapides comparativement à la
QCT périphérique qui, elle, peut nécessiter plusieurs minutes. Dans le cadre de cette
étude, nous avons évalué la justesse et la fidélité d'un fantôme de QCT préparé à
la main pour des tomodensitomètres hélicoïdaux pour corps entier dans le contexte
des évaluations quantitatives.
Matériaux et méthodes
Le fantôme pour l’étalonnage de la QCT comprenait une matière plastique et une solution
de K2HPO4 qui servaient de base et de référence respectivement. Des matériaux de référence
dont les concentrations de K2HPO4 étaient de 0, 50, 100, 200, 400, 1000 et 1200 mg/cm3 en solution aqueuse ont été utilisés. Pour créer le fantôme, nous avons eu recours
au logiciel ABAQUS.
Résultats
Nous avons utilisé les fantômes créés pour évaluer le rendement de la méthode de QCT
en mesurant les erreurs de justesse et de fidélité, qui étaient, de façon générale,
inférieures à 5,1% pour diverses concentrations. La corrélation entre les données
de tomodensitométrie et les concentrations se rapprochaient d'un (R2 = 0,99).
Discussion
Puisque les tomodensitomètres hélicoïdaux pour corps entier permettent de déterminer
la densitométrie osseuse centrale, le fait d’évaluer la justesse et la fidélité du
fantôme d’étalonnage facile pourrait améliorer le test de densitométrie osseuse effectué
au moyen de la QCT.
Conclusion
Cette étude a permis d’établir la stabilité du fantôme d’étalonnage K2HPO4 au cours d'une période limitée de trois mois. De plus, la grande plage dynamique
des concentrations pourrait servir à quantifier la faible et la forte densité des
os avec un pourcentage d'erreur relative acceptable.
Keywords
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Article Info
Publication History
Published online: November 09, 2018
Identification
Copyright
© 2018 Published by Elsevier Inc. on behalf of Canadian Association of Medical Radiation Technologists.
