CHEN Xiao,CAO Guoquan,PAN Yong, et al. Influence of spectral CT monochromatic imaging in combination with iterative reconstruction algorithm on image quality[J]. JOURNAL OF WEZHOU MEDICAL UNIVERSITY, 2016, 46(9): 633-637.
Abstract：Objective: To explore the effect of spectral CT monochromatic imaging in combination with adaptive statistical iterative reconstruction (ASiR) algorithm on the spatial resolution, density resolution and low-contrast detectability (LCD) of image in energy spectrum scanning. Methods: Catphan 500 phantoms were scanned using Gemstone Spectral CT. The images were reconstructed for 10 level of single energy from 45 keV to 135 keV, and meanwhile, the ASiR was applied to each keV from 10% to 100%. The CTP528 and CTP515 Catphan phantoms were used to measure the spatial resolution and density resolution, respectively. CTP515 cylinder phantoms with contrast ratio of 1% and diameter of 9.0 mm were chosen as research subjects to analyze low-contrast detectability (LCD) of images. The image quality was compared with multiple factors analysis of variance. Results: In a certain ASiR, as for spatial resolution, the distinguishable line pair per centimeter from 45 keV to 135 keV were 7, 7, 6, 6, 6, 6, 6, 6, 6 and 6 LP/cm, respectively. The density resolution and LCD decreased with the increasing of keV, and reached peaks at 55 and 65 keV. Different single energy was statistically significant (P<0.05) on the spatial resolution, density resolution and LCD. When keV was fixed, ASiR was statistically significant (P<0.05) on the density resolution and LCD, while there was no statistical difference on spatial resolution (P>0.05). Conclusion: Low single energy (45 keV to 65 keV) combined with 20% ASiR can achieve relatively high image quality in energy spectrum scanning with 5 mm slice thickness.
