CORE PROJECT I: SPECTROSCOPIC METHODS

~1H磁共振成像可以获得不同大脑的代谢图 N-乙酰天冬氨酸、肌酸、胆碱类化合物， 乳酸和谷氨酰胺。通过实施改进的采购 技术已经有可能进一步改善空间 这些代谢物图谱的分辨率。通过使用宽带水/脂肪 抑制信噪比测量序列中的重聚焦脉冲 (信噪比)已得到改善。使用较短的 循环延迟tr允许收集更大的数据集，用于 提高了空间分辨率。有了这种方法，就有可能 以获得空间分辨率为0.175 cc的1H MRSI数据集。 这种改进的空间分辨率对于 对中风患者和颞叶癫痫患者的检查。 1H MRSI技术的进一步改进正在进行中， 特定的多切片功能，以覆盖更大一部分 大脑。4.1T高对比度T1加权1H磁共振图像 使人可以将图像分割为灰色和白色物质。这 信息已经被用来确定灰质/白质 对1H MRSI测量的单个体素的贡献，以及这 信息被用来获得不同的测量结果 灰质和白质的代谢物比例和浓度 将图像分割方法应用于31P数据集，以 测量灰质和白质的聚合酶链式反应/三磷酸腺苷和聚合酶链式反应/PI 也是 TCA循环活动可以在人脑中通过以下方式测量 监测大脑谷氨酸中13C标记的出现 池，在输注[1-13C]-葡萄糖后。这些测量结果 已被延长，以获得TCA的单独测量 灰质和白质的循环率。 同核编辑技术得到了进一步改进，以 在人脑的1H MRS谱中发现隐藏的共振， 特别是观察GABA、谷氨酸的变化。贡献来自 大分子对GABA的共振已经降低，通过使用 改进的编辑脉冲。这些技术被用来遵循 正在服用抗癫痫药物的癫痫患者体内的GABA水平。

1H MRSI allows one to obtain metabolic maps of different brain compounds such as N-acetyl aspartate, creatine, choline compounds, lactate, and glutamine. By the implementation of improved acquisition techniques it has been possible to further improve the spatial resolution of these metabolite maps. By using a broad-band water/fat suppressing refocusing pulse in the measuring sequence the SNR (signal-to-noise ratio) has been improved. The use of a shorter recycle delay TR allows one to collect larger data sets, for a improved spatial resolution. With this approach it has been possible to obtain 1H MRSI data sets with a spatial resolution of 0.175 cc. This improved spatial resolution is especially important for the examination of stroke patients, and of temporal lobe epilepsy. Further improvements of the 1H MRSI technique are underway, in particular multislice capabilities to cover a larger part of the brain.  The high-contrast T1 weighted 1H MR images obtained at 4.1T allows one to segment the images in gray and white matter. This information has been used to determine the gray/white matter contribution to individual voxels of 1H MRSI measurements, and this information has been used to obtain separate measurements of metabolite ratios and concentrations of gray and white matter, This image segmentation approach has been applied to 31P data sets, to obtain measurements of PCr/ATP, and PCr/Pi for gray and white matter as well The TCA cycle activity can be measured in the human brain, by monitoring the appearance to the 13C label in the brain glutamate pool, following infusion with [1-13C]-glucose. These measurements have been extended, as to obtain separate measurements of the TCA cycling rate of gray and of white matter. Homonuclear editing techniques have been further improved, to uncover hidden resonances in the 1H MRS spectrum of the human brain, in particular to observe GABA, and glutamate. Contributions from macro molecules to the GABA resonance has been reduced, by the use of an improved editing pulse. These techniques are being used to follow GABA levels in epilepsy patients, who are on anti-seizure medication.