身体指数与主动脉和肝脏CT强化程度的相关性研究

目的探讨上腹部CT增强扫描时,身高(HT)、全体重(TBW)、体重指数(BMI)、去脂肪体重(LBW)、体表面积(BSA)和血容量(BV)与主动脉和肝脏强化程度的相关性。方法回顾性分析2014年7月至8月广东省人民医院行肝脏CT多期增强扫描的113例患者,测量上述身体指数和肝动脉期主动脉、门静脉期肝脏的强化值(ΔHU)。将主动脉和肝脏ΔHU值根据患者的性别、TBW和BMI各分成亚组,分别是男性组和女性组,TBW<60 kg组和TBW≥60 kg组,BMI<25 kg/m^2组和BMI≥25 kg/m^2组,采用t检验比较不同亚组患者主动脉、肝脏ΔHU值的差异。各身体指数与每克碘主动脉、肝实质增强值(ΔHU/gI)的相关性采用线性回归分析。结果男性患者肝动脉期主动脉的ΔHU、门静脉期肝实质的ΔHU均低于女性患者,差异均有统计学意义(P<0.05)。TBW<60 kg患者的主动脉和肝脏的ΔHU值均高于TBW≥60 kg患者,差异有统计学意义(P<0.05);BMI<25 kg/m^2和BMI≥25 kg/m^2患者的肝脏ΔHU差异有统计学意义,BMI<25 kg/m^2患者高于BMI≥25 kg/m^2患者(P<0.05)。15例患者肝脏ΔHU低于50 HU,男性比例(18.3%,11/60)高于女性(7.5%,4/53)。肝动脉期主动脉ΔHU/gI值与LBW的负相关程度最明显(r=-0.559,P<0.01),门静脉期肝脏ΔHU/gI值与BSA的负相关程度最明显(r=-0.680,P<0.01)。结论主动脉、肝脏CT增强扫描时,可采用LBW或BSA代替TBW作为个性化计算碘对比剂用量的身体指数。

The aortic and hepatic contrast enhancement at CT and its correlations with various body size index

Objective To evaluate the effect of height(HT),total body weight(TBW),body mass index(BMI),lean body weight(LBW),body surface area(BSA)and blood volume(BV)on aortic and liver contrast enhancement during upper abdominal contrast-enhanced CT scans.Methods One hundred and thirteen enrolled patients underwent upper abdominal multiphase contrast-enhanced CT scans.The enhancement(ΔHU)of aorta in hepatic arterial phase and liver parenchyma in portal venous phase were measured and calculated.TheΔHU values difference of aorta and liver parenchyma in subgroups between males and females,TBW<60 kg and TBW≥60 kg,BMI<25 kg/m^2 and BMI≥25 kg/m^2 were compared.To evaluate the effect of the patient′s body parameters on aortic and hepatic enhancement,we performed simple linear regression analyses between the change in CT numbers per gram of iodine(ΔHU/gI)at aorta and liver and each of the following:HT,TBW,BMI,LBW,BSA,and BV.Pearson and t test were used.Results The meanΔHU values of aorta and liver were significantly lower at males than that of at females(P<0.05).They were higher at TBW<60 kg patients than at TBW≥60 kg patients(P<0.05),and the meanΔHU values of the liver at BMI<25 kg/m^2 patients were significantly higher than at BMI≥25 kg/m^2 patients(P<0.05).The proportion of theΔHU values at liver less than 50 HU was higher at males(18.3%,11/60)than at females(7.5%,4/53).The most obvious negative correlation coefficients were found between theΔHU/gI of aorta and LBW at hepatic arterial phase(r=-0.559,P<0.01),and between theΔHU/gI of liver and BSA at portal venous phase(r=-0.680,P<0.01).Conclusion LBW or BSA could be the alternative body index to TBW for the calculation of personalized iodine dose protocol at aortic and liver enhanced CT scans.