Imaging Technology
The effect of CT detector width and signal acquisition positions on image quality
Guo Senlin, Ren Yue, Zhang Yongxian, Kang Tianliang, Liu Yunfu, Zhu Lei, Niu Yantao
Published 2023-06-10
Cite as Chin J Radiol, 2023, 57(6): 684-688. DOI: 10.3760/cma.j.cn112149-20230223-00126
Abstract
ObjectiveTo evaluate the influence of different detector widths and signal acquisition positions of wide-detector CT in different scanning modes on CT number and noise, and to provide a basis for reasonable selection of scanning modes and related parameters in clinical practice.
MethodsThe body dose phantom was scanned by GE Revolution CT. The scan was performed with detector widths of 40, 80 and 160 mm in sequential scanning mode and with detector width/pitch combinations of 40 mm/0.516, 40 mm/0.984, 80 mm/0.508 and 80 mm/0.992 in spiral scanning mode. The phantom was placed at the central and peripheral of the selected detector widths, and the adjacent positions between two axial scans. The images of the phantom were evaluated subjectively and the CT numbers and SDs were measured. The differences between the measured values at different imaging parameters were compared. The multi-group Friedman test was used to compare CT numbers and SD under different scanning parameters in sequential scanning mode, and the Wilcoxon test was used to compare CT numbers and SD in spiral scanning mode.
ResultsThere was no statistically significant difference in the geometric shapes of the phantom images obtained at any combination of parameters. In sequential scanning mode, the differences at different detector widths were statistically significant (χ2=14.00,P=0.001) with CT numbers at 40 mm and 160 mm greater than CT numbers at 80 mm (P<0.05). The differences at different signal acquisition positions were statistically significant (χ2=12.04,P=0.002) with CT numbers at peripheral and adjacent greater than CT numbers at central (P<0.05). In spiral scanning mode CT numbers at detector width at 80 mm were greater than CT numbers at 40 mm (Z=-2.10, P=0.036). For SD, the differences at different detector widths were statistically significant in sequential scanning modes (χ2=8.17,P=0.017) with SD at 160 mm greater than SD at 80 mm (P<0.05). The differences at different signal acquisition positions were statistically significant (χ2=13.50, P=0.001) with SD at peripheral greater than SD at central (P<0.05). In spiral scanning mode SDs at pitches 0.984 and 0.992 were greater than SDs at 0.516 and 0.508 (Z=-2.66, P=0.008). There were no significant differences among other groups.
ConclusionThe selection of scanning mode, detector width and signal acquisition position of wide-detector CT will affect the image CT numbers and SDs.
Key words:
Tomography, X-ray computed; Detector width; Image quality
Contributor Information
Guo Senlin
Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
Ren Yue
Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
Zhang Yongxian
Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
Kang Tianliang
Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
Liu Yunfu
Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
Zhu Lei
Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
Niu Yantao
Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
