Evaluation of the effect of coronary artery stenoses on perfusion imaging in Dual Energy Computed Tomography

Aim: To evaluate how myocardial perfusion is affected by coronary artery stenoses, hypertension, diabetes mellitus, hyperlipidemia, age and gender differences by Dual Energy Computed Tomography without any stressor test or intravenous medical agent. Materials and Methods: In our study, we analyzed the data of 348 patients who underwent Dual Energy Coronary Computed Tomography with Siemens 256 slice (Somatom Drive, Siemens Healthineers, Germany) tomography device between 14.06.2021 and 07.02.2024 in the Department of Radiology, Manisa Celal Bayar University Hafsa Sultan Hospital. Data analysis was performed retrospectively. Exclusion criteria for the case and control groups were images containing artifacts of suboptimal quality, age less than 18 years, and age older than 75 years. All images in the PACS (Picture Archiving Communication Systems) system at the hospital were evaluated in detail. In 111 patients, no coronary calcific plaque was found. A control group was formed with these, 111 patients were randomly selected to form a case group. Age, gender, presence of hypertension, diabetes mellitus, hyperlipidemia, percentage of stenosis in LAD, LCx and RCA arteries, iodine contrast density values in 17 segments of the left ventricular wall, presence of stable and unstable angina were recorded. Care was taken to ensure that the case group and control group patients had similar demographic characteristics. Results: There were significant differences between the case group and the control group in the presence of hypertension, hyperlipidemia and diabetes mellitus. Significant differences were found between the case group and the control group in age, LAD, LCx and RCA stenoses. The mean percentage of LAD stenoses in the case group was 37.43%, LCx 15.95% and RCA 23.68%. A significant difference was found between gender and RCA stenosis. The mean percentage of RCA stenosis was 17.91% in men and 8.79% in women. A significant difference was found between the presence of hypertension and age, LAD and RCA stenoses. The mean age was 52.94 years in patients with hypertension and 45.94 years in patients without hypertension. The mean LAD stenosis was 33.49% in patients with hypertension. It was measured as 15.63% in patients without hypertension. RCA stenosis was measured as 27.02% in patients with hypertension and 11.01% in patients without hypertension. A significant association was found between diabetes and LAD and RCA stenosis. The percentage of stenosis in LAD and RCA increased in the presence of diabetes. The mean percentage of LAD stenosis was 37% in diabetics and 18.79% in non-diabetics. RCA stenosis was measured as 27.73% on average in diabetics. In those without diabetes, it was 14.70% on average. Hyperlipidemia was significantly associated with age, LAD, LCX and RCA stenoses. The mean percentage of LAD stenosis was 42.74 in patients with hyperlipidemia and 15.78 in those without hyperlipidemia. The mean percentage of LCX stenosis was 30.91 in patients with hyperlipidemia and 9.26 in patients without hyperlipidemia. RCA stenosis was measured as 37.22% in patients with hyperlipidemia and 12.20% in patients without hyperlipidemia. In our study, it was found that the areas under the curve in the ROC curve analysis were not significant, and perfusion imaging, which is one of the functional measurements in Dual Energy Cardiac Computed Tomography in cardiac imaging, had no diagnostic value in the evaluation without the use of any stressor agent. Conclusion: Computed tomography provides non-invasive information about hemodynamic changes in recent years as well as plaque anatomy imaging. There is not enough information about CTP, which is one of the methods used for hemodynamic information, in the literature. In the literature, there are mostly studies using a stressor agent (adenosine, dipyramidol, etc.). According to the information obtained in these studies, there are perfusion differences in normal, ischemic and infarcted segments in CBCT images made with the use of a stressor agent and CBCT is the preferred method to show these differences compared to other invasive and non-invasive examinations. However, the evaluation of CTP images obtained without the use of any stressor agent has not been adequately studied. In our study, CTA and CTP images obtained simultaneously without the use of any stressor agent were evaluated and no significant correlation was found between hemodynamic changes caused by coronary artery stenoses and changes in iodine densities on CTP imaging. However, perfusion defects were found to be prominent in patients with severe stenosis or infarction. CBCT is an auxiliary and supportive diagnostic test to CTA. This issue will be better understood as the studies on this subject continue in the coming years. Keywords: Coronary computed tomography perfusion imaging, coronary CTA, coronary artery disease, cardiac imaging, radiology, Dual energy computed tomography