经静脉二次谐波超声造影对正常兔肝造影分期的声学定量分析

Acoustic densitometric analysis of phases in normal rabbit liver contrast enhancement using intravenous second harmonic imaging

目的 利用声学定量技术对正常兔肝的超声造影分期进行探讨。方法 对 10只健康大白兔进行二次谐波超声造影 ,观察经耳缘静脉注射造影剂时 ,门静脉主干血流阻断前后 ,肝组织声学定量 (AD)曲线形态及测值变化 ;及经耳缘静脉和经肠系膜静脉注射造影剂时 ,肝组织AD曲线形态及测值变化。结果 经耳缘静脉注射造影剂 ,正常兔肝组织AD曲线形态呈单峰形 ,近似直角三角形 ,可分为上升段、高峰段和下降段 ,峰值密度(PI)值为 (18.4± 1.7)dB。上升段为肝动脉期 ,高峰段和下降段均为门静脉期 ;门静脉主干血流阻断后 ,肝组织AD曲线形态与阻断前基本相似 ,但峰值略减低 ,其PI值平均减低 2dB。经耳缘静脉注射造影剂后 10～ 15s再经肠系膜静脉注射造影剂 ,肝组织AD曲线呈“驼峰征” ,第二个峰高于第一个峰。结论 正常兔肝声学造影肝动脉期短暂 ,门静脉期长。肝组织回声增强主要由于肝动脉来源造影剂所致 ,门静脉来源造影剂增强幅度低 。

Objective To investigate phases in normal rabbit liver contrast enhancement with the acoustic densitometry(AD).Methods Ten cases of normal rabbit were examined with second harmonic imaging(SHI).The AD curves and data of parenchyma were compared before and after the portal blood flow was blocked,when the contrast agents were administrated through ear veins.The AD curves and data of parenchyma were also investigated when the contrast agents were injected via ear veins and mesenteric veins.Results The curves of normal rabbit liver parenchyma were single-peak-shaped,looking like 'a verticle triangle',when the contrast agent was administrated through ear veins.The curve was divided into 3 sections: ascending,summit,descending,with the value of peak intensity ( 18.4 ± 1.7 )dB.Ascending section indicated the arterial phase,and summit and descending sections the portal phase.The AD curves were quite similar before and after the portal blood flow was blocked,only with the peak value slightly decreased,and the values of peak intensity decreasing by 2 dB.Two peaks were seen in the 'Hump-like' AD curves in the parenchyma,with the second peak higher than the first,as the contrast agents were administrated through mesenteric veins again 10-15 seconds after administration via ear veins.Conclusions The arterial phase is short and portal phase is long in normal rabbit liver contrast sonography.The enhancement of parenchyma is caused mostly by contrast from hepatic artery,and the contrast from portal veins only plays a minor role.