小型猪正常门静脉系统规范化磁共振血管成像实验研究

目的 以数字减影血管造影(DSA)为金标准,规范正常中国小型猪门静脉磁共振血管成像(MRA)技术.方法 实验用健康中国小型猪16只,在全麻下以门静脉主干为中心行MR灌注扫描,生成门静脉时间-信号曲线,以获得其MR最佳成像时间.待实验动物体内造影剂代谢24h后,依据前述成像时间,行MR冠状位脂肪抑制三维快速扰向梯度回波序列增强扫描,行多平面容积重建,显示门脉主干、属支,在MRA测量门静脉主干及属支直径.之后行经肠系膜上动脉及脾动脉DSA间接门静脉造影,并测量显影血管的管径；随机选择经肠系膜上动脉门静脉造影计算门静脉系统最佳显影时间.分别对比分析MRA及DSA两种技术下测量的门静脉系统直径、最佳显影时间.结果 (1)MRA与DSA门静脉最佳显影时间分别为(31.81±2.03)s与(14.32±0.71)s,MRA测得的门静脉最佳显影时间明显长于DSA(P ＜0.05),二者具有良好的相关性(r=0.749,P＜0.05).(2)MRA测得的门静脉主干、肠系膜静脉及脾静脉管径分别为(8.82±0.78)mm、(7.04±0.85)mm及(5.83±0.61)mm,DSA前述相应血管直径分别为(7.65±1.17)mm、(5.74±1.05)mm及(5.01±1.00) mm,MRA测定结果均高于DSA(P ＜0.05),二者均具有良好的相关性(r值0.949、0.910、0.906,均P＜0.05).结论 规范化门静脉MRA能准确评价门静脉系统,为实验性肝硬化门脉高压规范化MRA研究奠定基础.

Experimental study on standardizing magnetic resonance portal venography in healthy piglets

Objective To standardize the technique of magnetic resonance （MR）portal venography in healthy piglets by utilizing digital subtraction angiography （DSA） as the gold standard. Methods Sixteen healthy piglets were enrolled into this study and underwent MR perfusion scans in the condition of general anesthesia, and the dynamic scanning volume encompassed the main portal vein. By the GE perfusion commercial software, the timesignal curve of portal vein was generated automatically to obtain the time of portal vein peak enhancement for optimizing imaging time of MR portal venography. Twenty-four hours after the dynamic study, the fat-suppressed three-dimensional fast gradient echo sequence （3D FSPGR）MR coronal enhancement scanning was carried out in the experimental animals according to the above-mentioned optimal imaging time of MR portal venography, and the coronal imaging data were used for multiplanar volume reconstruction to display the main portal vein and principal branches and measure their caliber, Subsequently, each piglet underwent indirect portography via superior mesenteric artery and splenic artery to demonstrate the mesenteric veins, splenic vein and main portal vein, and to measure their caliber. The data of indirect portography via superior mesenteric artery were randomly selected for calculating the best portal vein imaging time by this angiography. The optimal imaging time of portal venography, or the diameters of the main portal vein（MPV）and branches between MR and DSA were statistically analyzed. Results （1）The optimal imaging time of MR portal venography was significantly longer than that of DSA venography （31.81 ± 2. 03 ）s vs. （ 14. 32 ± 0. 71 ） s, respectively, P 〈 0. 05 ], but there was a good correlation between MR and DSA （ r = 0. 749, P 〈0.05）. （2）The diameters of MPV, superior mesenteric vein and splenic vein on MR portal venography were significantly larger than those on DSA venography （ 8.82 ± 0. 78 ）mm vs. （ 7.65 ± 1.17 ） ram, （ 7. 04 ± 0. 78 ）mm vs. （5.74 ± 1.05 ） ram, and （ 5.83 ± 0. 61 ）mm vs. （5.01 ± 1.00） ram, respectively, all P 〈 0. 05], but there were significant correlations（ r = 0. 949,0. 910,0. 906, respectively, all P 〈 0. 05 ）. Conclusions The standard MR portal venography can be helpful fbr accurately evaluating the porta/system ,which might be the model for the further study on developing the standard MR portal venography technique used in experimental portal hypertension secondary to liver cirrhosis.