Gd-DTPA对不同器官质子3.0T MR波谱预扫描的影响

目的 探讨Gd-DTPA对头部、肝脏及肾脏在体3.0T单体素PRESS序列质子MR波谱(MRS)匀场线宽(LW)与抑水率(WS%)的影响.方法 使用GE Signa Excite HD 3.0T超导磁共振扫描仪,8通道头颈联合相控阵线圈采集头部波谱,8通道相控阵线圈采集肝脏及肾脏波谱.执行波谱常规自动预扫描程序,记录LW及WS%指标后进行波谱采集,然后注射Gd-DTPA,完成常规扫描后重新执行预扫描程序记录上述数值.采用配对样本符号秩和检验比较注射Gd-DTPA前后上述指标的差异.结果 注射Gd-DTPA后,头部波谱(T_+=12,T_-=66,P=0.02)及肝脏波谱(T_+=0,T_-=45,P=0.007)WS%均变差.肾脏波谱匀场(T_+=0,T_-=435,P<0.001)和WS%(T_+=0,T_-=435,P<0.001)均变差.结论 对于三个器官,Gd-DTPA均负性影响WS%;Gd-DTPA对肾脏的匀场影响最大,对头部及肝脏波谱采集匀场影响较小.推荐在注入Gd-DTPA前采集肾脏实质波谱.

Effect of intravenous Gd-DTPA on 3.0T MR spectroscopy prescan of different organs

Objective To evaluate the effect of intravenous Gd-DTPA on 3.0T proton MR spectroscopy (MRS) water suppression and shimming. Methods Prospective study of proton MRS was performed with GE Signa Excite HD 3.0T system and eight-channel phased-array coils with PRESS sequence (head, liver and kidney, respectively). Routine auto prescan program was operated to record full width half maximum (FWHM) and water suppression (WS%). Routine scan was performed after injection of Gd-DTPA, then prescan program was reoperated to record FWHM and WS%. The data of FWHM and WS% in head, liver and kidney were compared between before and after injection of Gd-DTPA with the Wilcoxon matched pairs signed test. Results WS% of spectroscopy of head and liver after administration of Gd-DTPA decreased significantly (T_+=12, T_-=66, P=0.02; T_+=0, T_-=45, P=0.007). The effect of shimming of kidney after administration of Gd-DTPA was poor (T_+=0, T_-=435, P<0.001) and WS% of spectroscopy of kidney after administration of Gd-DTPA decreased significantly (T_+=0, T_-=435, P<0.001). Conclusion WS% of spectroscopy in head, liver and kidney can be impacted negatively by Gd-DTPA. Gd-DTPA has great influence on shimming of spectroscopy of kidney, but has little influence on shimming of spectroscopy of head and liver. It is better to acquire MRS data before administration of contrast medium in kidney.