Iodine Content for Diagnostic AccuRacy and Patient Comfort For Individuals Undergoing Cardiac Computed Tomography (CT) Scanning

Coronary Cardiac CT (CCTA) is a widely accepted modality for non-invasive evaluation of coronary atherosclerosis. The diagnostic performance of CCTA for detecting coronary artery plaque burden has been validated in numerous studies, reaching a negative predictive value of 99%. The current gold standard for anatomic coronary imaging is Invasive Coronary Angiography (ICA) which portends a small but significant procedural-related complication of 1.7%. Non-invasive coronary imaging has the potential to replace ICA but the variability in diagnostic performance of CCTA remains under study. Among the potential variables causing differences in diagnostic performance is perhaps the degree of opacification of coronary artery by iodinated contrast. While numerous contrast agents exist, those that provide improved low and high contrast resolution (for delineating plaque from arterial wall and lumen from plaque, respectively) are hypothetically, the most optimal agents. To date, however, this has not been well evaluated. Further, use of a contrast agent which maximizes patient comfort is desired, as this may reduce heart rate increases and heart rate variability, which may in turn improve diagnostic image quality of CCTA. We hypothesize that the use of lower iodine content iso-osmolar agent - iodixanol - will improve diagnostic performance and patient comfort, as compared to higher iodine content low osmolar iodinated contrast - iopamidol.