Trial of Magnetic Resonance Imaging (MRI) of neurotransmitter in the brain

点击翻译按钮获取中文摘要

In order to obtain the magnetic resonance spectroscopic imaging (MRSI) of neurotransmitter in the brain, the new technique called SIDAC (spectroscopic imaging by sephasing amplitude change) was transplanted to the ordinary high resolution NMR spectrometer (4.7 T, 9 cm bore, JEOL). Using the system, MRSI of standard solution of lactate and amino acids with high concentration were successfully obtained. However, it was difficult to get MRSI of these compounds with low consentration and from the rat brain. This is due to the problems of low homogeneity in the whole regions of the magnet and the difficulty of rapid changing of gradient magnetic fields. As the second series of experiment, a 2.0 T MRI/S system (100 cm bore, Asahi Medical) was used to get MRSI of standard solution, rabbit brain and human arms. In this experiment also, MRSI could be obtained from the standard solution but not from the rabbit brain and human arms. These problems are attribute to the lacking of appropriate water suppression technique and the difficulties of getting the high homoneity of magnetic field. The water suppression technique used was the pre-saturation at the moment, that could suppress the water signal at the rate of 1/100. To suppress the water signal at the rate of 1/1000 or 1/1000, another thechnique such as 1-3-3-1 method is neccessary to be used and is now going to be examined. So far as using 2.0 T machine, the signal intensity is not strong enough to get MRSI of low content substances practically. From this experiment, it is concluded that MRSI of neurotransmitter in the brain in very important and it is possible to succeed it if the high field magnet such as 4.7 T or more (7.0 T is preferable) is applied.