Figure 2: Comparison of the original and noise-reduced basis material (water) density images from a dual-energy abdominal CT exam of a patient. (a) Original water density image. (b) Noise-reduced water density image using the ACNR algorithm [12]. In spite of the fact that the noise in the image is reduced, artifacts are evident throughout the liver area. (c) Original iodine density image. The iodinated hepatic vessels correlate well with the artifacts in the water density image, suggesting that the artifacts are caused by cross-contamination.