中文摘要：

目的探讨质子MR波谱（^1H—MRS）采集参数，包括线圈类型、TE、信号采集次数（NSA）及感兴趣容积（VOI）大小对在体肝脏预扫描匀场、抑水、谱线信噪比（SNR）及基线稳定性的影响。方法使用GE Signa Excite HD3．0T超导MR扫描仪对46名受检者进行检查，采用8通道相控阵线圈和内置体线圈。每名受检者行1～6次不等的单体素点分辨波谱（PRESS）序列^1H—MRS采集，共得到169条谱线。每名受检者首次使用参数均为TR1500ms、TE30ITIS、NSA64次、VOI2cm×2cm×2cm及8通道相控阵线圈（首次采用的参数记为A）；然后利用扫描操作界面的复制功能，复制首次扫描及定位参数，确保波谱采集位置一致，改变下列参数之一，线圈类型、TE、NSA及VOI重复采集（改变后的参数记为B）。对水峰的半高全宽（FWHM）、抑水率（WS）、基线稳定性、SNR的每对（A与B）数据评分进行比较，A好于B记为1分，A与B相似记为0分，A差于B记为-1分。对获得的数据统计采用配对样本符号秩和检验。结果8通道相控阵线圈（A）较体线圈（B）所获谱线（n=11）SNR高（-1分0对，0分1对，1分10对，Z=-3．162，P=0．002），而FWHM较大（-1分8对，0分2对，1分1对，Z=-2．511，P=0．012）。TE为30ins（A）时较TE90ms（B）所获谱线（n=13）SNR高（-1分2对，0分0对，1分11对，z=-2．496，P=0．013），但是基线稳定性差（-1分10对，0分2对，1分1对，Z=-2．333，P=0．020）。VOI为2cm×2cm×3cm（B）时较VOI为2cm×2cm×2cm（A）所获谱线（n=10）SNR高（-1分6对，0分4对，1分0对，Z=-2．449，P=0．014），但是FWHM较大（-1分0对，0分5对，1分5对，Z=-2．041，P=0．041）。NSA为128次（B）时较NSA为64次（A）所获谱线（n=29）SNR高（-1分21对，0分7对，1分1对，Z=-4．264，P=0．000）。结论在体肝脏单体素3．0T ^1H—MRS采集时，推荐使用VOI为2cm×2cm×3cm、NSA为128次。体线圈及更

英文摘要：

Objective To characterize the effect of the 1H-MRS scan parameters, including the type of coil, TE, NSA and VOI, on shimming, water suppression, spectral signal to noise ratio （SNR） and the stability of the baseline of liver in vivo. Methods ^1H-MRS of liver in vivo was performed prospectively on GE Signa Excite HD 3.0 T system in 46 volunteers. Point-resolved spectroscopy （PRESS） sequence with built-in body coil and eight-channel torso phased-array coils was applied. After the localized scan, the first PRESS sequence with a TR of 1500 ms ,TE of 30 ms, VOI of 2 cm× 2 cm × 2 cm and NSA of 64 times was acquired using eight-channel torso phased-array coils. （The first PRESS sequence parameters was deemed as A）. Then, the sequence was repeated with alteration of the three parameters including the type of coil, TE and size of VOI. （ Changed parameters deem as B）. The data were analyzed with the Wilcoxon matched pairs signed test. 0 mark ： A is similar to B, 1 mark ： A better than B, - 1 mark ： A worse than B. Results SNR（ - 1 mark 0 pair,0 mark 1 pair,1 mark 10 pair, Z = -3. 162,P =0. 002） was better in data （n = 11 ） with eight-channel torso phased-array coils （A） than that with the built-in body coil （B）, but the auto- shimming line width with eight-channel torso phased-array coils were inferior to those with built-in body coil （ - 1 mark 8 pair,0 mark 2 pair,1 mark l pair, Z = -2. 511 ,P =0. 012）. SNR was better in data （n = 13） with TE of 30 ms（A） than that at the sequence with TE of 90 ms（B） （ - 1 mark 2 pair,0 mark 0 pair, 1 mark 11 pair, Z = - 2. 496 ,P = 0. 013 ） , whereas baseline stability was poorer in the former（ - 1 mark 10 pair,0 mark 2 pair,l mark 1 pair, Z= -2. 333,P =0. 020）. SNR at the sequence （n = 10） with VOI of 2 cm ×2 cm×3 cm （B）was better（ - 1 mark 6 pair,0 mark 4 pair,1 mark 0 pair, Z = -2. 449,P = 0. 014） than that at the sequence （n = 29） with VOI of 2 cm × 2 cm × 2 cm（A）, but poorer （ -1 mark 0 pair,0