Abstract 12679: Objective Analysis Of Myocardial Ischemia Using Iodine Image Of Dual-energy Computed Tomography: Comparison With 99mTc-stress Perfusion Spect
Purpose: Dual-energy computed tomography (DECT) can extract iodine distribution in myocardium (iodine image). Despite the increasing number of studies demonstrating the feasibility of iodine image to detect myocardial ischemia or infarction, most of them were evaluated subjectively, thus being susceptible to inter-observer difference. Here we propose objective method for quantitative iodine image using DECT and aim to validate its accuracy in comparison to 99mTc-stress perfusion SPECT images.
Methods: We retrospectively enrolled 43 (female/male= 8/35, mean age=70.7±9.8) consecutive patients referred for cardiac CT and stress perfusion 99mTc-SPECT myocardial perfusion image (MPI) within one month. DECT examination was performed using dual-source CT scanner (Somatom Definition FLASH) with dual-energy mode and single-color coded iodine images were reconstructed along with making CT angiography (CTA) images. The regions of interest (ROI) were manually set as recommended by AHA 17 segment model on CT images, transferred to iodine image of the same section and measured. Because contrast enhancements depend on patient’s body weight and iodine dose, the ROI values were divided by iodine amount (mg) per unit weight (kg). The value was defined as the perfusion value of the segments and cut-off value was defined as 0.28 by ROC analysis. For statistical analysis, iodine image was compared with 99mTc- stress perfusion SPECT images in every segment according to AHA 17 segment model. In addition, we evaluated the performance of “iodine-image with CTA” in comparison with “SPECT with CTA” on a vessel territory basis analysis.
Results: Segment base analysis of iodine map encompassing total 731 segments demonstrated that a sensitivity, specificity, positive predictive value, and negative predictive value was 93.3%, 98.9%, 77.8% and 99.8%, respectively, and analyses of iodine image with CTA showed that each of those values was 100%, 99.1%, 92.3%, 100%, respectively.
Conclusions: Objective analysis of iodine image of CT at rest demonstrated high sensitivity and specificity comparable with stress perfusion image using 99mTc-SPECT, and thus iodine image of DECT will allow for the accurate diagnosis of significant stenosis of coronary arteries.
- © 2013 by American Heart Association, Inc.