OA161] Quantification of low contrast resolution and noise of dual energy CT using software for automated quality control

Abstract

Purpose The first aim of this study was to perform quantification analysis of low contrast resolution and corresponding parameters like noise of dual energy CT using CATPHAN phantom and ARTISCAN software. The second aim was to determine the optimal parameters dual energy CT for monoenergetic scans with the best image quality. Methods The ability of dual-energy computed tomography (CT) to differentiate materials with similar CT number but different atomic composition makes this method very interesting for many clinically applications. Dual-energy CT could also improve quality of images like low contrast and noise. To evaluate low contrast resolution two sets of CATPHAN phantom scans using dual-energy mode (80 and 140 keV) were acquired on CT Siemens Definition AS. This phantom has special modules for low contrast and noise evaluation. Then sixteen monoenergetic series were created using dedicated software from Siemens. Scans were created every 10 keV from 40 keV to 190 keV. Next the ARTISCAN software from Aquilab was used for analysis. This software using mathematical formulas provide quantitative information about detected and undetected disc, SNR and noise. For all scans low contrast resolution, signal to noise ratio and noise was computed and compared between each monoenergetic series. Results All monoenergetic series were analyzed using ARTISCAN software. This program provides quantitative and objective analysis of evaluated parameters. For every sets low contrast resolution and noise were computed and evaluated. The best low contrast resolution was obtained for 60 keV and 70 keV. Next evaluated parameter was noise. The smallest value therefore the best was for 60 keV and was 0,42%. For comparison the biggest value was 2,19% for 40 keV. Conclusions In this study a significant difference between low contrast resolution and noise for different energies have been observed. For improve low contrast resolution and noise dual energy CT can be used. The best results for every evaluated parameters were obtained for 60 keV. In future reconstructed monoenergetic scans for 60 keV will be analyzed for clinical use for tumor delineation.