Quantitative Analysis of Iodine Image of Dual-energy Computed Tomography at Rest: Comparison With 99mTc-Tetrofosmin Stress-rest Single-photon Emission Computed Tomography Myocardial Perfusion Imaging as the Reference Standard.

Abstract Dual-energy computed tomography (DECT) can be used for visual determination of iodine distribution in the myocardium (iodine image); however, the accuracy and reproducibility of the process remains debatable. Because of the low contrast-to- noise ratioof CT, we hypothesized that quantitative measurement may be more accurate for detecting myocardial ischemia. In this study, we evaluated our quantitative method by comparing it with visual analysis using Tc-tetrofosmin (TF) stress-rest single-photon emission computed tomography(SPECT) myocardial perfusion imaging(MPI) as the reference standard. Forty-three patients who had a significant stenosis on cardiac rest DECT and had received Tc-TF stress-rest SPECT MPI within 1 month were retrospectively analyzed. The regionsof interestwere set on iodine images in accordance with the American Heart Association (AHA) 17-segment model (a total of 731 segments). The regionsof interestvalues were divided by the amount of iodine (mg) per unit weight (kg) and defined as perfusion value (perfusion value analysis). All segments were also visually analyzed and receiver operating characteristiccurve analysis performed to identify the superior analysis. The receiver operating characteristiccurve analysis showed that perfusion value analysis is significantly superior to visual analysis [the area under the curve: 0.921 (95% confidence interval, 0.860-0.981) versus 0.685 (95% confidence interval, 0.580-0.791), respectively, P