Application of Dual-Layer Detector Spectral CT Combined With Half Volume Contrast Agent in the Detection of Liver Metastases
10.3969/j.issn.1005-5185.2024.07.010
- VernacularTitle:双层探测器光谱CT联合半量对比剂检测肝转移瘤的应用
- Author:
Chengle MA
1
,
2
;
Dejun SHE
;
Feng WANG
;
Fan ZHANG
;
Ruiquan CHEN
;
Dairong CAO
Author Information
1. 福建医科大学附属第一医院医学影像科,福建 福州 350005
2. 福建医科大学附属第一医院滨海院区国家区域医疗中心医学影像科,福建 福州 350005
- Keywords:
Liver metastases;
Spectral CT;
Contrast agent;
Image quality
- From:
Chinese Journal of Medical Imaging
2024;32(7):692-698
- CountryChina
- Language:Chinese
-
Abstract:
Purpose To explore the clinical application value of dual-layer detector spectral CT combined with half volume contrast agent in detecting the liver metastases in portal vein phase.Materials and Methods Ninety-six patients with liver metastases diagnosed by liver enhanced CT in the First Affiliated Hospital of Fujian Medical University from November 2021 to June 2022 were prospectively studied.They were randomly divided into two groups by using the contrast agent administration calculation method based on body surface area.The conventional polyenergetic image(CI)of patients in the conventional contrast agent group(48 cases with 18.6 gI/m2 body surface area iodine contrast agent)was constructed in the portal vein phase,and the 40-70 keV(5 kiloelectron voltage)virtual monoenergetic imaging(VMI)was reconstructed for patients in the semi contrast agent dose group(48 case with 9.3 gI/m2 body surface area iodine contrast agent).The image noise,CT value and contrast noise ratio in the two groups were measured and compared.Besides,the image quality was scored with a 5-point method,and the consistency of subjective scores between two radiologists were evaluated.Results The VMI noise at 40-70 keV was(10.26±1.38)Hu,(9.59±1.35)Hu,(9.15±1.31)Hu,(8.80±1.32)Hu,(8.58±1.31)Hu,(8.40±1.31)Hu and(8.27±1.33)Hu;while the CI noise was(10.86±1.13)Hu.It revealed that the VMI noise at 45-70 keV was lower than the CI noise(t=-3.885,-5.343,-6.449,-7.180,-7.756 and-8.132,P<0.001).There was no significant difference between VMI and CI noises at 40 keV(t=-1.800,P>0.05).With the decrease of energy level,CT value of normal liver parenchyma,and contrast noise ratio values of liver parenchyma and liver metastases gradually increased,at the 40 keV level,the values of which were(148.31±21.34)Hu,8.81±2.83 and 8.18±2.85;at the 45 keV level,the values were(130.10±16.95)Hu,7.66±2.46 and 7.48±2.55;at the 50 keV level,the values were(116.19±13.55)Hu,6.60±2.08 and 55.40±13.77,reaching the highest at 40 keV level,while the CI values were(118.02±7.02)Hu,5.69±1.11 and 5.77±1.41.Therefore,the value of 40 keV and 45 keV VMI was significantly higher than CI(t=3.804,4.883,4.462,all P<0.05;t=2.854,3.465,3.378,all P<0.05),respectively.There was no significant difference between 50 keV VMI and CI(t=-0.612,1.739,2.208,P>0.05).The subjective score in the overall quality of VMI images was higher than that of CI at 40-50 keV(t=9.628,7.508,3.514,P<0.05).The subjective scores of the two physicians were good consistent among image contrast,image noise and overall image quality(Kappa=0.766,0.749 and 0.661,P<0.05),respectively.Conclusion VMI at 40-50 keV can provide better image quality and display ability of liver metastases than CI images at portal vein phase with a 50%reduction in contrast agent dose.
