Image Quality of Contrast-enhanced Hepatic CT Using Iterative Reconstruction Technique at Different Radiation Doses
10.3969/j.issn.1005-5185.2015.01.004
- VernacularTitle:迭代模型重建技术不同辐射剂量对肝脏CT增强扫描图像质量的影响
- Author:
Dan PAN
;
Yan JIANG
;
Xin CHEN
;
Meng LI
;
Changhong LIANG
;
Zaiyi LIU
- Publication Type:Journal Article
- Keywords:
Liver diseases;
Liver;
Tomography,X-ray computed;
Iterative reconstruction algorithm;
Image enhancement;
Radiation dosage;
Quality control
- From:
Chinese Journal of Medical Imaging
2015;(1):10-13,18
- CountryChina
- Language:Chinese
-
Abstract:
Purpose To compare the image quality of contrast-enhanced hepatic CT using iterative reconstruction technique (IMR) at different radiation doses, and to explore the value of IMR in contrast-enhanced hepatic CT under different radiation doses. Materials and Methods Fifty-four cases undergoing contrast-enhanced hepatic CT were divided into two groups using different portal-venous phase protocols:29 cases in group A (120 kV, 250 mAs), 25 cases in group B (80 kV, 500 mAs). Portal venous phase CT images were reconstructed using IMR and filtered back projection to obtain 4 data sets:group A1 (120 kV, FBP), group A2 (120 kV, IMR), group B1 (80 kV, FBP) and group B2 (80 kV, IMR). Images were evaluated for noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) as well as low contrast detectability (LCD), image distortion (ID) and diagnostic confidence (DC). Effective radiation dose was recorded. Results The effective radiation dose in group B was 42.7%, lower than that in group A (t=15.27, P<0.001). Image noise in group A2 and B2 was significantly lower than that in group A1 and B1, with higher SNR and CNR (Fnoise=81.98, FSNR=65.19, FCNR=37.42, P<0.001). There was significant statistical difference in LCD among four groups, A2>B2>A1>B1 (χ2=58.21, P<0.001), and in image distortion, A1>B1>A2>B2 (χ2=12.94, P<0.001). There was significant difference between B2 and A1, and between B2 and B1 (P<0.05). For diagnostic confidence, the score was A2>A1>B2>B1 (χ2=34.06, P<0.001). There was no statistical significance between group A1 and group B2 (P>0.05). Conclusion Compared with FBP, IMR technique can reduce image noise and improve image quality at low and high radiation doses, with better effect on low dose (80 kV, 500 mAs) hepatic CT.
