扩散加权磁共振波谱采集策略优化：门控及循环模式影响

文玉林, 李改英, 武玉朋, 李建奇

Optimization of DW-MRS Acquisition Protocol: The Impact of Gating and Cycling Modes

WEN Yulin, LI Gaiying, WU Yupeng, LI Jianqi

图2 两种循环模式示意图. (a) b值内循环，b值循环位于累加循环内侧，即先依次循环采集不同b值数据，再进行下一次累加采集；(b) b值外循环，b值循环位于累加循环外侧，即先累加采集完某一b值数据，再采集下一个b值数据. b0表示不施加扩散梯度时的信号；b1-LR、b1-AP和b1-HF表示扩散梯度分别施加在受试者的左右、前后或头脚方向时的信号. 蓝色、橙色、黄色和紫色分别表示b0、b1-LR、b1-AP和b1-HF

Fig. 2 Illustration of the two cycling modes. (a) Internal cycling of b-values: The b-value loop occurs within the accumulation loop, where data from different b-values are sequentially looped and collected before proceeding to the next accumulation. (b) External cycling of b-values: The b-value loop occurs outside the accumulation loop, with data for the same b-value first accumulated before moving on to the next b-value. The b0 denotes the signal when no diffusion gradient is applied. b1-LR, b1-AP, and b1-HF represent the signals when the diffusion gradient is applied in the left-right, anterior-posterior, and head-foot directions of the subject respectively. Blue, orange, yellow, and purple indicate b0, b1-LR, b1-AP, and b1-HF respectively