Fig. 1.

Example of CTs with filtered back projection (FBP) versus iterative reconstruction (IR) at standard radiation dose (“Std.”) and low radiation dose (“Low”). There is a circle signifying the region of interest (ROI) in the ascending aorta measuring the image noise as the standard deviation of the ROI in Hounsfield units (HU). Image noise is the highest for low dose FBP, while image noise between Std. Dose FBP and Low Dose IR is similar as evidenced by the HU measured by the ROI and the degree of pink speckling identified by the CAC scoring software. a Low Dose IR; b Std. Dose FBP; c Std. Dose IR; d Low Dose FBP