双低剂量4D-CT灌注替代常规肝脏四期CT成像可行性研究

Feasibility of dual low dose 4D-CT perfusion replacingconventionalfour-phase liver imaging:a preliminary study

目的:探讨双低剂量4D-CT灌注替代常规肝脏四期CT成像的可行性。方法:对30例肝脏疾病患者行肝脏CT平扫、低辐射剂量及低对比剂浓度的4D-CT灌注成像及延时期成像,通过使用动态血管成像软件对多期灌注图像进行处理,得到融合后平扫期、融合后动脉期、融合后静脉期。对比双低剂量4D-CT灌注总辐射剂量与常规肝脏四期CT成像辐射剂量,融合后平扫图像与常规平扫图像在信噪比、对比噪声比上的差异,并采用主观评分的方法对融合后平扫、融合后动脉期、融合后静脉期图像进行评分。结果:双低剂量肝脏4D-CT灌注成像患者接受的碘剂浓度较低,总辐射剂量为1129.0(1087.0~1296.0) mGy·cm,常规肝脏四期CT成像辐射剂量为(1265.9±284.3) mGy·cm(P=0.136),两者差异无统计学意义;融合后平扫信噪比5.9(4.8~7.1),常规平扫信噪比5.8±1.9(P=0.360),两者差异无统计学意义,融合后平扫肝脏对比噪声比0.90±0.62,常规平扫肝脏对比噪声比1.06(0.61~1.40),P=0.153,两者差异无统计学意义。4D灌注融合后平扫、融合后动脉期、融合后静脉期图像质量主观评分均≥3分,图像质量满足诊断需求。结论:双低剂量4D-CT灌注替代常规肝脏四期CT成像是可行的,不仅可以得到灌注信息,还能使用动态血管成像软件处理后所得到的融合后平扫、动脉期、静脉期图像能够满足临床诊断需求。

Objective:To preliminarily investigate the feasibility of dual low dose 4D-CT perfusion replacing conventional four-phase liver imaging.Methods:Non-contrast-enhanced CT scan,dual low dose 4D-CT perfusion imaging and delayed imaging of liver were performed in 30 patients with liver diseases.Dynamic angiography software was used to process the CT perfusion images,and the fusion CT plain scan,fusion arterial phase and fusion portal venous phase images were obtained.We compared the total radiation dose of dual low-dose 4D-CT and conventional 4-phase CT imaging of the liver,signal-to-noise ratio and contrast noise ratio of liver between the CT plain scan image and the fusion plain CT scan image.Subjective scoring method was used to evaluate the fused plain scan images,the fused arterial phase images and the fused portal venous phase images.Results:The intaking of iodine was lower in patients with dual low dose liver 4D-CT perfusion imaging.The total radiation dose of dual low dose liver 4D-CT perfusion imaging was 1129.0(1087.0~1296.0)mGy·cm,and the radiation dose of conventional 4-phase CT imaging was(1265.9±284.3)mGy·cm(P=0.136).The SNR of fused plain scan image of liver was 5.9(4.8~7.1),while the SNR of conventional plain scan image was(5.8±1.9)(P=0.360).The CNR of fused plain CT scan image was 0.90±0.62,and the CNR of conventional plain CT scan image was 1.06(0.61~1.40)(P=0.153).The image quality of fused images can meet the diagnostic requirement with subjective score≥3 marks in fused plain CT scan images,the fused arterial phase and the fused portal venous phase images.Conclusions:It is feasible for dual low dose 4D-CT perfusion to replace conventional four-phase liver imaging.It can not only provide perfusion information,but can also obtain the fusion non-contrast-enhanced phase,arterial phase and venous phase images,providing valuable information for clinical diagnosis.