正常肝脏高机械指数谐波造影时间-强度曲线法定量分析

Quantitative analysis of time-intensity curve in normal liver using high mechanical index contrast harmonic imaging

目的探讨不同剂量及触发间隔对正常人肝脏造影效果的影响。方法选择10例正常人接受肝脏谐波超声造影检查,造影剂剂量分为0.1、0.3、0.5及0.7ml,触发间隔分为1.0、2.0、3.0及4.0s,分别观察造影剂量和触发间隔对正常人肝脏造影效果的影响。造影增强后图像灰阶变化用时间-强度曲线法进行定量分析,测量指标有峰值强度(PI)、曲线下面积(AUC)、峰值强度降半时间(HT)、平均渡越时间(MTT)。结果当剂量为0.3ml,触发间隔从1.0～3.0s时,PI、AUC、HT、MTT测值均逐渐增大,并在3.0s时达到最大值;当触发间隔为4.0s时,各项测值与3.0s时测值相近,差异无统计学意义(P>0.05)。当触发间隔为3.0s,剂量从0.1～0.7ml,AUC、HT、MTT测值均随剂量增大而增大,组间比较差异有非常显著性(P<0.01)。而PI值在剂量0.1～0.3ml之间,随剂量增大而增大,差异有非常显著性(P<0.01);从0.3～0.7ml,PI值并不随剂量增大而显著增大,差异无统计学意义(P>0.05)。结论肝脏造影增强效果受剂量和触发间隔的影响,正常肝脏造影增强最大PI值约为(23.64±3.30)dB,最佳剂量为0.3ml,最佳触发间隔为3.0s,AUC、HT、MTT3项指标则随剂量增大而增大。

Objective To quantitatively analyse time-intensity curve effects using contrast-enhanced harmonic imaging with high mechanical index in normal livers.Methods Ten normal liver cases underwent harmonic contrast imaging with doses set at 0.1,0.3,0.5,0.7 ml,respectively and trigger intervals set at 1.0 s,2.0 s,3.0 s,4.0 s,respectively.The grey scale changes of images enhanced by contrast agents were analyzed with time-intensity curve.The values of peak intensity(PI),area under the curve(AUC),half time of descending(HT)and mean transit time(MTT)were measured.Results When the dose was set at 0.3 ml,the values of PI,AUC,HT and MTT were gradually increased following trigger intervals increased from 1.0 s to 3.0 s and reached the ultimate value at 0.3 s.The values of PI、were almost similar with that measured at an interval of 3.0 s,with no significant difference(P>0.05).The values of AUC、HT、MTT were gradually increased along with the dosage increase from 0.1 ml to 0.7 ml as the intervals were set at 3.0 s.The differences among groups were significant(P<0.01).The value of PI was increased along with dosage increase from 0.1 ml to 0.3 ml(P<0.01),but it did not increase obviously with dosage increase from 0.3 ml to 0.7 ml(P>0.05).Conclusions The effects of contrast enhancement in the liver can be directly influenced by dosages and trigger intervals.The maximal PI value of contrast-enhanced imaging in the normal liver was about 23.64±3.30 dB,and the optimal dosages and intervals were 0.3 ml、3.0 s,respectively.The values of AUC,HT,MTT were increased with dosage increase.