【摘要】 目的　通过体模和动物模型实验研究 ,探索在 1.5TMR导向下经皮穿刺介入器械 (穿刺针 )显示最清楚、伪影最小以及成像时间最短的最佳MR成像方案。材料与方法　把具有MR兼容性之穿刺针插入琼脂胶体介质中 ,在 1.5T磁共振扫描仪上扫描 ,从成像方位、成像参数、成像序列等几个方面进行探索性MR成像。以上述目的为基础 ,进行 30只兔VX2 肝癌模型MR介入实验。同样改变进针的角度及成像参数、成像序列进行MRI扫描。结果　 (1)穿刺针在SE序列上为中间宽带低信号周围窄带高信号 ;在GRE序列上全部为低信号带。 (2 )当穿刺针长轴与B0 平行时 ,其信号呈S样改变 ,随着穿刺针长轴与主磁场B0 的角度增加 ,显示穿刺针横径增加。 (3)当穿刺针长轴与B0 平行时 ,无论频率编码方向与长轴平行或垂直 ,在FSPGR序列产生的伪影大小与在FSE序列产生的伪影并无明显区别 ,且信号表现在同一序列上变化也不明显 ;当穿刺针长轴与B0 垂直时 ,在FSPGR序列产生的伪影直径远远大于在FSE序列产生的伪影 ,且当频率编码方向由与长轴平行改为垂直时 ,对于FSPGR序列 ,伪影直径无明显变化 ,但是对于FSE序列 ,伪影直径明显加宽。结论　FSET2 WI是 1.5TMR导引经皮穿刺介入的最佳扫描序列。当穿刺针长轴与B0 垂直时 ,选择频率编码方向与穿刺针长轴垂更多还原

【Abstract】 Objective Through model and animal experiment to explore the best imaging technique, which is time-saving and produces finest image and least artifacts, for percutaneous hepatic puncturing under 1.5T MR-guidance. Materials and Methods In model experiment, MR compatible needle was inserted in agar medium, and MR scanning was performed on a closed-bore 1.5T MR unit (GE CT/i). Images with different directions, parameters and sequences were obtained. Based on the model experiment results, MR-guided puncturing was carried out in 30 rabbits with VX2 hepatic cancer model. Before puncturing, coronal scanning with SSFSE T 2WI or FSPGR T 1WI and axial scanning with SE T 1WI and FSE T 2WI were performed. The most suitable puncture point was determined, the puncturing depth and angle was measured on FSE T 2WI. When the puncturing was completed, SE, PSE, SSFSE, GRE and FSPGR sequences were used. MRI images with different sequences were evaluated and compared. Results (1) On SE sequence, the needle was presented as a central hypo-signal stripe with hyper-signal peripherally, while on GRE sequence it was totally hypo-signal. (2) When the needle was parallel with B 0, its signal showed “S” deformity. The needle’s width enlarged with the increasing of angle between the needle and B 0. (3) When the needle was parallel with B 0, the artifacts on FSPGR were quite the same as on FSE. If the needle was vertical to B 0, the artifacts on FSPGR were much larger than that on FSE.Conclusion FSE T 2WI is the best sequence for percutaneous hepatic puncturing under 1.5T MR-guidance. When the needle is parallel with B 0, the direction of frequency code should be vertical to the needle’s longitudinal axis, besides, short TE, long ETL, small BW, large FOV and little NEX should be adopted as possible as can.更多还原