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Proceedings Paper

Multi-energy spectral photon-counting CT in crystal-related arthropathies: initial experience and diagnostic performance in vitro
Author(s): Anais Viry; Aamir Y. Raja; Tracy E. Kirkbride; Chloe Choi; Lisa K. Stamp; Nicola Dalbeth; Christele Combes; Francis R. Verdun; Nigel G. Anderson; Fabio Becce
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Paper Abstract

Purpose: We aimed to determine the in-vitro diagnostic performance of multi-energy spectral photon-counting CT (SPCCT) in crystal-related arthropathies. Methods: Four crystal types (monosodium urate, MSU; calcium pyrophosphate, CPP; octacalcium phosphate, OCP; and calcium hydroxyapatite, CHA) were synthesized and blended with agar at the following concentrations: 240, 88, 46, and 72 mg/mL, respectively. Crystal suspensions were scanned on a pre-clinical SPCCT system at 80 kVp using the following four energy thresholds: 20, 30, 40, and 50 keV. Differences in linear attenuation coefficients between the various crystal suspensions were compared using the receiver operating characteristic (ROC) paradigm. Areas under the ROC curves (AUC), sensitivities, specificities, and diagnostic accuracies were calculated. Crystal differentiation was considered successful if AUC>0.95. Results: For each paired comparison of crystal suspensions, AUCs were significantly higher in the first energy range (20-30 keV). In the first energy range, MSU was confidently differentiated from CPP (sensitivity, 0.978; specificity, 0.990; accuracy, 0.984) and CHA (sensitivity, 0.957; specificity, 0.970; accuracy, 0.964), while only moderately distinguished from OCP (sensitivity, 0.663; specificity, 0.714; accuracy, 0.688). CPP was confidently differentiated from OCP (sensitivity, 0.950; specificity, 0.954; accuracy, 0.952), while only moderately from CHA (sensitivity, 0.564; specificity, 0.885; accuracy, 0.727). OCP was accurately differentiated from CHA (sensitivity, 0.898; specificity, 0.917; accuracy, 0.907). Conclusions: Multi-energy SPCCT can accurately differentiate MSU from CPP and CHA, CPP from OCP, and OCP from CHA in vitro. The distinction between MSU and OCP, and CPP and CHA is more challenging.

Paper Details

Date Published: 9 March 2018
PDF: 7 pages
Proc. SPIE 10573, Medical Imaging 2018: Physics of Medical Imaging, 1057351 (9 March 2018); doi: 10.1117/12.2293458
Show Author Affiliations
Anais Viry, Institute of Radiation Physics, Lausanne Univ. Hospital (Switzerland)
Aamir Y. Raja, Univ. of Otago, Christchurch (New Zealand)
Tracy E. Kirkbride, Ara Institute of Canterbury (New Zealand)
Chloe Choi, The Univ. of Auckland (New Zealand)
Lisa K. Stamp, Univ. of Otago, Christchurch (New Zealand)
Nicola Dalbeth, The Univ. of Auckland (New Zealand)
Christele Combes, CIRIMAT, Univ. de Toulouse, CNRS, INPT, UPS, ENSIACET (France)
Francis R. Verdun, Institute of Radiation Physics, Lausanne Univ. Hospital (Switzerland)
Nigel G. Anderson, The Univ. of Auckland (New Zealand)
Fabio Becce, Lausanne Univ. Hospital (Switzerland)

Published in SPIE Proceedings Vol. 10573:
Medical Imaging 2018: Physics of Medical Imaging
Joseph Y. Lo; Taly Gilat Schmidt; Guang-Hong Chen, Editor(s)

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