The influence of individualized low-dose CT imaging parameters on liver fat content measurement by quantitative CT
10.3969/j.issn.1002-1671.2024.10.032
- VernacularTitle:个体化低剂量CT成像参数对定量CT肝脏脂肪含量测量的影响
- Author:
Shiyu WANG
1
;
Yijun LIU
;
Wei WEI
;
Beibei LI
;
Xu WANG
;
Xiaoyu TONG
Author Information
1. 大连医科大学附属第一医院放射科,辽宁 大连 116011
- Keywords:
fat content;
automatic tube voltage modulation;
computed tomography;
radiation dose;
image quality
- From:
Journal of Practical Radiology
2024;40(10):1717-1721
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the influence of individualized low-dose CT imaging parameters on quantitative computed tomography(QCT)liver fat content measurement and image quality by using the combined technique of Auto-prescription and adaptive statistical iterative reconstruction(ASIR-V)algorithm with different weights.Methods A total of 231 patients who underwent both chest and abdominal CT scans were prospectively selected.The overlapping liver of two-position scans in the same case was studied,in which the chest was scanned with an individualized low-dose protocol(group A)and the upper abdomen was scanned with a routine 120 kVp protocol(group B).Patients with group A were scanned by using 80 kVp and 100 kVp based on Auto-prescription technique,and divided into the subgroups of A1 and A2;meanwhile the same patients with group B were scanned by using 120 kVp and divided into the subgroups of B1 and B2.The images were transferred to AW4.6 and QCTpro workstations for measuring CT values,standard deviation(SD)values and Fat％QCT values of the left lobe,right anterior lobe,and right posterior lobe of the liver in the overlapping regions.The signal-to-noise ratio(SNR)and contrast-to-noise ratio(CNR)were also calculated using the same-level erector spinae as background.Paired sample t-test was employed to compare the differences in Fat％QCT measurements between groups A and B.Spearman correlation analysis was conducted,and linear regression equations were established.Two observers evaluated image quality using a five-point scale and Kappa test was conducted to test inter-observer consistency.Results In group A,the Fat％QCT values showed no statistically significant difference among different weights of ASIR-V.However,the statistically significant difference was found between groups A and B(P＜0.05),and there were highly positive correlations between subgroups A1 and B1 and between subgroups A2 and B2(r=0.939 7,0.987 2,P＜0.05).The linear regression equation under 80 kVp and 100 kVp were as follows:y=0.976x+3.119,y=1.007x+2.041.The SNR and CNR of group A combined with post-60％ASIR-V were higher than those of group B combined with post-40％ASIR-V under conventional tube voltage.The subjective scores between groups A and B had no statistically significant difference.Conclusion Low-dose chest imaging based on Auto-prescription technique combined with post-60％ASIR-V can not only satisfy clinical diagnostic requirement,but also realize quantitative analysis of Fat％QCT under low tube voltage(80 kVp/100 kVp).
