Image quality and coronary blood flow assessment: The influence of radiographic contrast

The growth of percutaneous coronary intervention has been fostered by technological progress in many areas, including vast improvements in angiographic image quality. Achieving optimal outcomes in coronary intervention requires real-time review of detailed, high resolution images of the coronary vasculature. The role of radiographic contrast in obtaining optimal coronary angiograms is often overlooked. We studied the image quality provided by 4 different contrast agents, using an in-vitro model to simulate coronary vessels. Phantom vessels, ranging from 0.5 to 3.0 mm in diameter, were filled with 1 of 4 contrasts, which varied with respect to chemical composition and iodine concentration. The contrast compounds employed were: 1. ioxaglate (320 mgI/ml), 2. iodixanol (320 mgI/ml), 3. iopamidol (370 mgI/ml), and 4. iomeprol (400 mgI/ml). Radiographic images of these contrast filled phantoms were obtained in a catheterization suite using a Philips Digital Cardiac Imaging system. Quantitative analysis of these image data demonstrated that the peak and mean videodensity was directly related to the iodine concentration of the agents being studied. Qualitative analysis of image pairs, graded by 8 angiographers blinded to the contrast used to generate them, demonstrated a clear preference for the images obtained with the higher iodine containing contrast agents. Whether the improvement in image quality demonstrated in this in-vitro study will translate into clinically important differences in human coronary arteriography requires further investigation. However, review of the recent literature suggests that image quality enhancement improves diagnostic accuracy in cardiac angiographic procedures, such as the detection of coronary thrombi and coronary dissection.

Duke Scholars

Author John Kevin Harrison Medicine, Cardiology