Image quality and attenuation values of multidetector CT coronary angiography using high iodine-concentration contrast material: A comparison of the use of iopromide 370 and iomeprol 400

Background: Effects of high iodine-concentration contrast material on the image quality of coronary CT angiography (CCTA) have not been well evaluated. Purpose: To compare the image quality and attenuation values of CCTA between patients administered iopromide 370 and iomeprol 400 with the use of 64-slice multidetector CT. Material and Methods: Patients were prospectively enrolled and were randomized into two groups (group A, 151 patients received iopromide 370, iodine flux = 1.48 g I/s; group B, 146 patients received iomeprol 400, iodine flux = 1.60 g I/s). CT attenuation was measured in the coronary arteries and great arteries and measurements were standardized based on an iodine flux of 1.50 g I/s. The image quality of 15 coronary artery segments was graded by two radiologists in consensus with the use of a four-point scale (1 = excellent to 4 = poor enhancement). Non-parametric statistical approaches were used to compare the two groups. Results: The median attenuation values in the coronary arteries were 454 HU and 464 HU for iopromide 370 and iomeprol 400, respectively, and they did not differ (P = 0.26). When standardizing for an iodine flux, significantly higher attenuation values were found for iopromide 370 (median = 460 HU, range = 216-791 HU) compared with iomeprol 400 (median = 435 HU, range = 195-758 HU) (P = 0.006). The median image quality score of coronary arterial segments was 1 (range 1-2) for both groups (P - 0.84). Conclusion: The attenuation values in the coronary arteries after injection of the same amount of two high iodine-concentration contrast materials at the same flow rate with different iodine fluxes are similar with no difference in image quality. With standardization for an iodine flux, the attenuation is significantly higher when using iopromide 370.