【摘要】 目的探讨1.5T磁共振仪行在体兔正常肌肉及VX2软组织肿瘤氢质子磁共振波谱(1H-MRS)检查的可行性及成像技术。材料与方法20只新西兰大白兔。右大腿近段肌肉内注射VX2肿瘤组织悬液0.2ml,制成肿瘤模型。分别于接种前及接种后第40d行正常大腿肌肉及肿瘤MRI和1H-MRS成像。波谱成像序列包括单体素和多体素点解析频谱(PRESS)序列,比较不同成像条件及参数下1H-MRS曲线,在工作站上测量胆碱(Cho)/肌酸(Cr)及脂质峰(Lipid)/Cr比值并进行统计学分析。结果所有兔正常肌肉及VX2肿瘤1H-MRS可见Cho峰、Cr峰及Lipid峰。与正常肌肉组织相比,VX2肿瘤组织Cho峰明显增高,Lipid峰降低。肿瘤组织与正常肌肉Cho/Cr及Lipid/Cr比值差异具有统计学意义。所有兔正常肌肉和VX2肿瘤的单体素PRESS序列成像质量优于多体素PRESS序列,冠状面定位优于横断面。单体素PRESS序列半高带宽(FWHM)小于8Hz,多体素FWHM小于12Hz,成像质量较好。根据采集兴趣区大小,调整视野或采集次数可提高波谱成像质量。实时测定兔体温并设定为波谱成像时的系统温度值可有效避免波峰漂移。结论在体1H-MRS检查兔VX2软组织肿瘤与正常肌肉1H-MRS表现明显不同,1H-MRS有望用于软组织肿瘤的诊断。优化成像条件与参数可明显提高波谱成像质量。更多还原

【Abstract】 Objective To discuss the feasibility and technique of the proton magnetic resonance spectroscopy (~1H-MRS) of normal muscle tissues and VX2 soft tissue tumors in rabbits.Materials and Methods 20 Newzealand white rabbits were implanted with 0.2ml VX2 tumor tissue suspension in the right proximal thighs. We performed MRI and ~1 H-MRS of normal muscle tissue and VX2 soft tissue tumors in all rabbits before implantation and 40 days after implantation respectively. The ~1 H-MRS sequences included single voxel and multi voxel point resolved spectroscopy(PRESS) sequences. The proton MR spectrums in different parameters were reviewed. Cho/Cr and Lipid/Cr were measured on workstation and a statistic test was done.Results Choline containing compounds(Cho), creatine(Cr) and lipid peak were seen in the ~1 H-MRS of normal muscle and VX2 soft tissue tumors in all rabbits. The ~1 H-MRS in VX2 soft tissue tumors showed prominent Cho peak and decreased Lipid peak. The differences of Cho/Cr and Lipid/Cr between VX2 soft tissue tumors and normal muscles were statistically significant. The spectrum quality of single voxel PRESS sequence and based on coronal scout view were superior to that of multi voxel PRESS sequence and based on axial scout view both in normal muscle and in VX2 soft tissue tumors. When the FWHM was 8Hz in single voxel PRESS sequence or 12Hz in multi voxel PRESS sequence, the quality of MR spectrum was good. As the different size of region of interested (ROI), FOV and acquisition numbers should accordingly be adjusted, which could improve the quality of ~1 H-MRS. The drift of the peaks of metabolics could be prevented by monitoring the body temperature of rabbits and regulating the system temperature.Conclusion There is great difference in vivo ~1 H-MRS of the normal muscle and VX2 soft tissue tumor of rabbits, and ~1 H-MRS is a feasible technique for the evaluation of soft tissue tumors. The optimization of ~1 H-MRS techniques and parameters can greatly improve the imaging quality.更多还原