RESUMO
The aim of this study was to inspect the usefulness of relative artifact index (AIr), which divided artifact index (AI) by standard deviation of the noise image for noise-independent evaluation of the streak artifact in computed tomography images. A water phantom without/with a cylindrical phantom filled with diluted contrast medium was scanned with different tube voltages (100/120/140 kV) and radiation doses (5/10/20 mGy), then images were reconstructed with different kernels (B10/30/50f). AI, location parameter in Gumbel method and AIr were measured in each condition and compared. The higher tube voltage or radiation dose or lower spatial resolution kernel, the lower quantitative values were presented by both AI and Gumbel method. AIr showed quantitative values independent of radiation dose and kernel, and substantial artifact amounts affected only by tube voltage. Our results showed AIr can evaluate quantitative artifact amount independent of image noise.
