9 March 2018 Determination of the limit of detection for iodinated contrast agents with multi-energy computed tomography
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Multiple studies in the literature have proposed diagnostic thresholds based on Multi-Energy Computed Tomography (MECT) iodine maps. However, it is critical to determine the minimum detectable iodine concentration for MECT systems to assure the clinical accuracy for various measured concentrations for these image types. In this study, seven serial dilutions of iohexol were made with concentrations from 0.03 to 2.0 mg Iodine/mL in 50 mL centrifuge tubes. The dilutions and one blank vial were scanned five times each in two scatter conditions: within a 20.0 cm diameter (Head) phantom, and a 30.0 cm x 40.0 cm elliptical (Body) phantom. This was repeated on a total of six scanners from three vendors: fast-kVp switching, dual-source dual-energy CT, dual-layer detector CT, and split-filter CT. Scan parameters and dose were matched as closely as possible across systems, and iodine maps were reconstructed. Regions-of-Interest (ROIs) were placed on 5 consecutive images within each vial, for a total of 25 measurements per sample. The mean and standard deviation were calculated for each sample. The Limit of Detection (LOD) was defined as the concentration that had a 95% chance of having a signal above the 95% confidence interval of the measured blank samples. The range of LODs was 0.021 – 0.484 mg I/mL in the head phantom and 0.125 – 0.547 mg I/mL in the body phantom. The LOD for iodinated contrast using MECT systems changed with scatter and attenuation conditions. The limit of detection for all conditions was under 0.5 mg Iodine/mL.
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Megan C. Jacobsen, Megan C. Jacobsen, Xinhui Duan, Xinhui Duan, Dianna D. Cody, Dianna D. Cody, Erik Cressman, Erik Cressman, Dawid Schellingerhout, Dawid Schellingerhout, Rick R. Layman, Rick R. Layman, } "Determination of the limit of detection for iodinated contrast agents with multi-energy computed tomography", Proc. SPIE 10573, Medical Imaging 2018: Physics of Medical Imaging, 105734Q (9 March 2018); doi: 10.1117/12.2293935; https://doi.org/10.1117/12.2293935

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