| CHEN Wei,LIU Jin-kang,OU Xiao-guang.Analysis of aliasing artifacts in 16-slice helical CT[J].Chinese Journal of Radiological Medicine and Protection,2006,26(6):619-622 |
| Analysis of aliasing artifacts in 16-slice helical CT |
| Received:April 18, 2006 |
| DOI： |
| KeyWords:Tomography X-ray computed Quality control Artifacts Aliasing |
| FundProject: |
| Author Name | Affiliation | E-mail | | CHEN Wei | Department of Radiology, Xiangya Hospital, Central South University, Changsha 410008, China | chenwei_rt@sina.com | | LIU Jin-kang | Department of Radiology, Xiangya Hospital, Central South University, Changsha 410008, China | | | OU Xiao-guang | 410008 长沙, 中南大学湘雅医院设备科 | | | 李文政 | Department of Radiology, Xiangya Hospital, Central South University, Changsha 410008, China | | | 廖伟华 | Department of Radiology, Xiangya Hospital, Central South University, Changsha 410008, China | | | 严昂 | 410008 长沙, 中南大学湘雅医院设备科 | |
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| Abstract:: |
| Objective To recognize the features of aliasing artifacts on CT images, and to investigate the effects of imaging parameters on the magnitude of this artifacts. Methods An adult dry skull was placed in a plastic water-filled container and scanned with a PHILIPS 16-slice helical CT. All the acquired transaxial images by using several different acquisition or reconstruction parameters were examined for comparative assessment of the aliasing artifacts. Results The aliasing artifacts could be seen in most instances and characterized as the spokewise patterns emanating from the edges of high contrast structure as its radius varies sharply in the longitudinal direction. The images that scanned with pitch of 0.3, 0.6 and 0.9, respectively, showed aliasing artifacts, and its severities increased with pitches escalated (detector combination 16× 1.5, reconstruction thickness 2 mm); There were more significant aliasing artifacts on the images reconstructed with 0.8 mm slice width compared with 1-mm slice width, and no aliasing artifacts were observed on the images reconstructed with 2-mm slice width (detector combination 16×0.75, pitch 0.6); No artifacts were perceived on the images scanned with detector combination 16×0.75, while presented evidently with the use of detector combination 16×1.5 (pitch 0.6, reconstruction thickness 2 mm);The degrees of aliasing artifacts were unaltered when reconstruction interval and tube current changed. Conclusions Aliasing artifacts are caused by undersampling. When the operator choose the thinner sampling thickness, lower pitch and a much wider reconstruction thickness judiciously, aliasing artifacts could be effectively mitigated or suppressed. |
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