Non-invasive analyses of brain metabolic function in dementia

1.带有水冷套的局部梯度线圈和合适的RF线圈新纳入成像仪系统。利用该梯度/RF线圈组件，可以在用于功能MRI的回波平面（EPI）型快速扫描中获得高分辨率MR图像，例如，具有128 × 128像素的MR图像<13>。本实验室在临床影像学的基础上，结合异质核多共振技术，研制了一种新型的多功能磁共振成像系统.将富含^ C的葡萄糖注射<13>到活体器官中，通过^1H-检测的^ C体内MR光谱进行非侵入性追踪<13>。注射后30分钟血糖达到最高值，1小时后迅速下降。与此相反，葡萄糖代谢反应产生的代谢产物谷氨酰胺和谷氨酸在给药后1小时达到最高水平 ...更多信息 然后在这个高水平上再保持大约两个小时。在此期间，利用化学位移成像技术能够获得这些代谢产物以及前体葡萄糖的分布.为了精确测量模型动物的血氧水平，研制了一种可见分光光度计。通过观察氧合血红蛋白和脱氧血红蛋白的Soret波段波长及其吸光度曲线的等吸光度点来提高血氧水平检测的灵敏度，其强度计算血红蛋白的每个组分的浓度，并且只要脑中血红蛋白的总浓度。该光度计的另一个特点是具有独立的两个探测器，可以同时测量大鼠大脑左右半球.还采用近红外光谱仪来非侵入性地监测血液中的氧水平。用于此目的的分光光度计具有750和830 nm光源和13通道检测器，由宾夕法尼亚大学Chance博士的实验室开发。利用该仪器，对患者大脑的血红蛋白氧合和血红蛋白总浓度进行评估，并且还在大约30秒内构建这些组分的图。少

1. A local gradient coil with water cooling jacket and a fitted RF coil were newly incorporated into imager system. With this gradient/RF coil assembly it is possible to obtain high-resolution MR images, for example, an MR image with 128 x 128 pixels, in echo-planar (EPI) type fast scanning for functional MRI.Further, a fast scanning EPI approach was incorporated into newly developed highly sensitive in vivo ^<13>C MR spectroscopy method, which was developed in our laboratory by the integration of hetero-nuclear multiple resonance capability with the basis of clinical imager.2. Injection of glucose enriched with ^<13>C into living organs was traced non-invasively by ^1H-detected ^<13>C in vivo MR spectroscopy. The level of the glucose reached to the highest mark in 30 minutes after the njection and followed rapid decrease with 1 hour. In contrast to this, the metabolites glutamine and glutamate produced by the metabolic reaction of the glucose reached to the highest level in 1 hour aft … More er the injection and stayed at this high level for approximately two more hours. In this period, it was able to obtain the distribution of these metabolites as well as the precursor glucose with chemical shift imaging.3. A visible spectrophotometer has been developed in order to precisely measure blood oxygen level in a model living animal. Sensitivity enhancement for blood-oxygen level detection was taken care by observing a Soret-band wavelengths for oxy and deoxy hemoglobin and their isosbestic point for the absorbance curves, whose intensities calculate the concentration of each component of hemoglobin and as long as the total concentration of hemoglobin in the brain. Another feature of the photometer is that this instrument has independent two detectors, which can simultaneously measure right and left hemisphere in rat brain.4. A near infra red spectrometer was also employed to non-invasively monitor oxygen level in blood. The spectrophotometer used for this purpose has 750 and 830nm light sources and 13 channel detectors, which was developed in Dr. Chance's laboratory at University of Pennsylvania. With this instrument oxygenation of hemoglobin and total concentration of hemoglobin were evaluated for patient brain and the maps of these components were also constructed in approximately 30 seconds. Less