Schäffter T, Börnert P, Leussler C, Carlsen I C, Leibfritz D
Philips Research, Department Technical Systems, Hamburg, Germany.
Magn Reson Med. 1998 Aug;40(2):185-93. doi: 10.1002/mrm.1910400204.
Fast proton magnetic resonance spectroscopic imaging (MRSI) using a multi-element head-coil array is examined with respect to three aspects: the coil design, the use of an appropriate signal combination method, and the design of the MRSI pulse sequence itself. An eight-element head-coil array has been developed to increase the signal-to-noise ratio (SNR) of MRSI in the human brain. The flexible wraparound design optimally fits different head sizes and thus provides high sensitivity. The signal combination of the individual coil elements is based on the approach proposed by Roemer et al. (Magn. Reson. Med. 16, 192 (1990)). An additional short prescan is performed to provide a good estimate of the complex coil sensitivity profiles, which are used in the signal combination procedure to correct the spectroscopic imaging data for the spatially varying intensity. The use of coil arrays in MRSI has some effect on the requirements for both water and lipid suppression. These techniques and a MRSI pulse sequence that provides a high spectroscopic resolution are described and discussed. Experimental results at 1.5 T show that metabolite maps of N-acetylaspartate (NAA), choline (Cho), phosphocreatine (PCr)/creatine (Cr) can be obtained within a 5-min acquisition time.
使用多元素头部线圈阵列的快速质子磁共振波谱成像（MRSI）从三个方面进行了研究：线圈设计、合适信号组合方法的使用以及MRSI脉冲序列本身的设计。已开发出一种八元素头部线圈阵列，以提高人脑MRSI的信噪比（SNR）。灵活的环绕式设计能最佳地适配不同的头部尺寸，从而提供高灵敏度。各个线圈元件的信号组合基于Roemer等人（《磁共振医学》16, 192 (1990)）提出的方法。额外进行一次短的预扫描，以提供对复线圈灵敏度分布的良好估计，这些分布在信号组合过程中用于校正空间强度变化的波谱成像数据。在MRSI中使用线圈阵列对水和脂质抑制的要求有一定影响。描述并讨论了这些技术以及提供高波谱分辨率的MRSI脉冲序列。1.5T的实验结果表明，在5分钟的采集时间内可以获得N-乙酰天门冬氨酸（NAA）、胆碱（Cho）、磷酸肌酸（PCr）/肌酸（Cr）的代谢物图谱。
