Hérigault G, Zoula S, Rémy C, Décorps M, Ziegler A
Laboratoire mixte INSERM U594, Université Joseph Fourier "Neuroimagerie fonctionnelle et métabolique", Laboratoire de Recherche Conventionné (30 V) du CEA, Centre Hospitalier Universitaire, pavillon, BP 217, 38043, Grenoble Cedex, France.
MAGMA. 2004 Dec;17(3-6):140-8. doi: 10.1007/s10334-004-0060-x. Epub 2004 Oct 26.
Two-dimensional J-resolved spectroscopy may be used to separate resonances which overlap in 1D NMR spectra. Coupled with spectroscopic imaging (SI), it would give unequivocal information on the distribution of such resonances. Multi-echo acquisition decreases the minimum experimental time of such 4D experiments. The water peak may be used for phase and chemical-shift reference. This study aimed to demonstrate the feasibility of J-resolved SI based on a multi-echo sequence and without water suppression, and its ability to separate the peaks for lactate and mobile lipid in a rat glioma. Experiments were performed on rat brain, without water suppression, at 7 T. The water signal was used for correcting the phase of the echoes. A FOCSY-like acquisition was used to collect the first part of the echoes at short echo times. Two different data processing methods were tested to overcome the problem of contaminations of metabolite signals by the intense water signal. Maps of N-acetylaspartate, choline, creatine, lactate and mobile lipids were obtained in vivo on a rat glioma in 70 min. The in-plane resolution was 2 mm2. The 2D spatially resolved, 2D J-resolved spectra enabled the separate mapping of lactate and mobile lipids.
二维J分辨光谱可用于分离在一维核磁共振谱中重叠的共振峰。结合光谱成像（SI），它能给出关于此类共振峰分布的确切信息。多回波采集减少了此类四维实验的最短实验时间。水峰可用于相位和化学位移参考。本研究旨在证明基于多回波序列且不进行水抑制的J分辨SI的可行性，以及其在大鼠胶质瘤中分离乳酸和可移动脂质峰的能力。实验在7T场强下对大鼠脑进行，不进行水抑制。水信号用于校正回波的相位。采用类FOCSY采集在短回波时间收集回波的第一部分。测试了两种不同的数据处理方法以克服强水信号对代谢物信号的污染问题。在70分钟内于活体大鼠胶质瘤上获得了N-乙酰天门冬氨酸、胆碱、肌酸、乳酸和可移动脂质的图谱。面内分辨率为2平方毫米。二维空间分辨的二维J分辨光谱能够分别绘制乳酸和可移动脂质的图谱。
