Reproducibility of calcium scoring of the coronary arteries: Comparison between different vendors and iterative reconstructions

Abstract

Purpose: To assess the reproducibility of coronary artery calcium scoring performed on four different computed tomography scanners, and compare the variability between two reconstruction algorithms, filtered back projection and iterative reconstruction. Materials and Methods: A coronary calcium scoring phantom was made from agar and contained 23 pieces of chicken bones. The phantom was scanned using four different computed tomography scanners (5 times each): Toshiba, GE, Philips, and Siemens. Images were reconstructed using the filtered back projection and iterative reconstruction algorithms. Agatston and volume scores of total bone fragments were calculated and the overall differences between the instruments were evaluated using the Friedman test. Comparison of the Agatston and volume scores between the two reconstruction algorithms, for each instrument, was evaluated using the Wilcoxon signed rank test. Results: The difference in the Agatston scores was significantly different between the four machines (P = 0.001). The Toshiba scanner yielded the highest score followed by Philips, GE, and Siemens scanners. There was no difference in the calcium scores evaluated using the two reconstruction algorithms, except in case of the Siemens scanner (P = 0.032). Conclusion: Coronary calcium scores performed on different scanners varied significantly. In the Toshiba, Philips, and GE scanners, there was no significant difference in the coronary calcium score determined using either an iterative reconstruction or the filtered back projection algorithm. In the Siemens scanner, applying the iterative reconstruction algorithm resulted in a slightly different coronary calcium score (mean 9.1), which might not be clinically significant.