双源 CT 低管电压结合低浓度对比剂在肝脏增强扫描中的应用

摘要

目的：探讨双源 CT 使用低管电压（100 kVp）和低浓度等渗对比剂（270 mg I／mL）进行肝脏增强扫描的可行性。方法：将我院108例行肝脏 CT 增强扫描的患者随机分成两组，每组54例。A 组：管电压100 kVp，对比剂为威视派克（270 mg I／mL）。B 组：管电压120 kVp，对比剂为碘克沙醇（320 mg I／mL）。测量、计算两组图像的对比噪声比（CNR）、信噪比（SNR）、肝实质 CT 值、肝动脉 CT 值、门静脉 CT 值及有效辐射剂量（ED），并对两组图像进行主观评分，对两组间上述指标进行统计学分析。结果：A 组的 CNR 高于 B 组，且差异具有统计学意义（t ＝2．88，P ＜0．05），SNR 高于 B 组（P ＜0．05），A 组能够提供清晰的诊断图像，提高病变的显示；A、B 组的图像质量评分差异无统计学意义（t ＝－0．58，P ＞0．05）；A、B 组的肝实质 CT 值及肝动脉 CT 值均无统计学差异（t＝－1．81，P ＞0．05；t＝0．96，P ＞0．05），而 A 组的门静脉CT 值高于 B 组（t＝7．55，P ＜0．05）；A 组的三期总辐射剂量[（8．04±1．12）mSv]低于 B 组[（11．62±2．41）mSv]（t ＝9．94，P ＜0．001）。结论：双源 CT 肝脏增强扫描采用管电压100 kVp 和低浓度等渗对比剂（270 mg I／mL）可以提供较好的图像 CNR，提高门静脉 CT 值，保证诊断图像质量的同时降低辐射剂量。%Objective:To explore the feasibility of dual-source CT using low tube voltage 100kVp and low concentra-tion 270mg I/mL isotonic contrast medium in enhanced imaging of the liver.Methods:108 patients having undergone CT en-hanced imaging were randomly divided into two groups:54 in each group.Group A:tube voltage was 100kVp,and contrast agent being visipaque (270mg I/mL).Group B:tube voltage was 120kVp,and contrast agent being iodixanol (320mg I/mL).Image contrast-to-noise ratio (CNR),image signal-to-noise ratio (SNR),hepatic parenchyma CT value,hepatic ar-tery CT value,and portal vein CT value were recorded and calculated.All the images of the two groups were given subjec-tive ratings and statistical analyses were made for all data of the groups.Results:The image contrast-to-noise ratio and sig-nal-to-noise ratio of group A were higher than that of group B,the difference was statistically significant (P <0.05),thus improving the display of the pathological changes.Scores for image noise and image quqlity were similar between the two groups,having no statistical significance (P >0.05).Liver parenchyma and hepatic artery CT values of the two groups had no statistical difference (P >0.05).Portal vein CT value of group A was higher than that of group B (P <0.05).The total radiation dose of three phases in groups A [(8.04±1.12)mSv]was lower than that in group B [(11.62±2.41)mSv,P <0.001],being reduced by about 30%.Conclusion:Dual-source CT enhancement imaging of the liver using tube voltage 100kVp and isotonic contrast medium in low concentration 270mg I/mL can provide better image contrast to noise ratio,in-crease the portal vein CT value,and reduce significantly the radiation dose on the basis of ensuring the quality of diagnostic images.