正常肝脏低剂量CT灌注研究

Low Dose CT Perfusion Imaging of Normal Liver

目的:通过比较不同管电流扫描情况下正常肝脏的灌注参数,评价低剂量肝脏CT灌注成像(CTPI)的可行性。方法:确诊无肝脏疾病的健康志愿者32例,随机分为3组,常规剂量组(140mA)、中等剂量组(90mA)和低剂量组(50mA)。比较两种兴趣区选择方式下各组所测量的肝脏灌注参数(HBF、HBV、HPI、MTT、PS、HAP及PVP)间的差异。结果:不同管电流扫描条件下肝脏CTPI均获得了较满意的图像质量及灌注参数,不同兴趣区选择方式下各灌注参数值间的差异无显著性意义(P>0.05)。常规剂量组测量的HPI值(t=-2.23,P=0.034)和低剂量组测量的MTT值(t=-2.25,P=0.042)在不同感兴趣区选择方式间略有差异。常规剂量、中等剂量和低剂量肝脏CTPI的有效剂量分别为19.62mSv、12.61mSv和7.01mSv,低剂量CTPI较常规剂量减少约64.27%的辐射剂量。结论:低剂量肝脏CTPI可以较常规剂量减少约2/3的辐射剂量,同时获得与常规剂量CTPI相当的灌注参数结果。

Objective：To evaluate the feasibility of low dose CT perfusion imaging （CTPI） of liver by comparing the normal liver perfusion parameters acquired with different tube currents. Methods：The CT perfusion of liver was performed in 32 normal volunteers, which were randomly divided into three groups with different tube currents applied,including conventional dose group （140mA）,median dose group （90mA） and low-doe group （50mA）.Perfusion parameters including hepatic blood flow （HBF）,hepatic blood volume （HBV）,hepatic perfusion index （HPI）,mean transit time （MTT）,permeability surface （PS）,hepatic arterial perfusion （HAP） and portal vein perfusion （PVP） with two selected methods of regions of interest （ROI） were compared.Results：Relatively satisfied image quality and perfusion parameters of liver CTPI could be acquired with different tube currents.There were no significant differences between the parameters acquired at different corresponding ROI （P〉0.05）.Slight differences were existed between different selected ROIs in HPI of conventional dose group （t=2.23,P=0.034） and MTT of low-dose group （t=-2.25,P=0.042）.The effective dosage of conventional,median and low dose liver CTPI were 19.62mSv,12.61mSv and 7.01mSv,respectively.The radiation dosage of low dose CTPI reduced for 64.27% as compared with that of conventional group.Conclusion：The radiation dosage of low-dose CTPI could be reduced by 2/3 when compared with that of conventional group and the results of perfusion parameters were about the same.