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Erschienen in:
01.02.2014 | Cardiac
Accuracy of dual-energy computed tomography for the measurement of iodine concentration using cardiac CT protocols: validation in a phantom model
Erschienen in: European Radiology | Ausgabe 2/2014
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Purpose
To assess the accuracy of dual-energy CT (DECT) for the quantification of iodine concentrations in a thoracic phantom across various cardiac DECT protocols and simulated patient sizes.
Materials and methods
Experiments were performed on first- and second-generation dual-source CT (DSCT) systems in DECT mode using various cardiac DECT protocols. An anthropomorphic thoracic phantom was equipped with tubular inserts containing known iodine concentrations (0–20 mg/mL) in the cardiac chamber and up to two fat-equivalent rings to simulate different patient sizes. DECT-derived iodine concentrations were measured using dedicated software and compared to true concentrations. General linear regression models were used to identify predictors of measurement accuracy
Results
Correlation between measured and true iodine concentrations (n = 72) across CT systems and protocols was excellent (R = 0.994–0.997, P < 0.0001). Mean measurement errors were 3.0 ± 7.0 % and −2.9 ± 3.8 % for first- and second-generation DSCT, respectively. This error increased with simulated patient size. The second-generation DSCT showed the most stable measurements across a wide range of iodine concentrations and simulated patient sizes.
Conclusion
Overall, DECT provides accurate measurements of iodine concentrations across cardiac CT protocols, strengthening the case for DECT-derived blood volume estimates as a surrogate of myocardial blood supply.
Key Points
• Dual-energy CT provides new opportunities for quantitative assessment in cardiac imaging.
• DECT can quantify myocardial iodine as a surrogate for myocardial perfusion.
• DECT measurements of iodine concentrations are overall very accurate.
• The accuracy of such measurements decreases as patient size increases.