脑功能核磁共振成像在精神疾病中的应用

主要介绍了几种脑功能核磁共振成像方法以及在精神疾病中的研究情况.血氧水平依赖fMRI (BOLD-fMRI)是目前应用最广泛的fMRI技术，可利用神经激活后对局部血流的影响，间接显示神经活动.灌注加权成像是直接测定脑血流的fMRI技术，但由于它的时间分辨率比较低，对快速的脑功能难以进行研究.扩散加权象目前主要用于脑缺血的早期诊断，利用该技术也可示踪神经通路.化学位移成像能够检测局部组织代谢产物的含量，可反映不同脑区能量和物质代谢的状况，也是一种脑功能的研究手段.尽管这些技术在神经、心理学领域已经取得非常可喜的进展，目前fMRI在精神疾病方面的工作较少，相信随着技术的改进，fMRI必将在精神疾病方面大显身手.

THE APPLICATION OF FUNCTIONAL MAGNETIC REGSONANCE IMAGING IN PSYCHIATRIC DISEASES

Magnetic Resonance Imaging(MRI) of the brain is well recognized for its excellent spatial resolution, allowing neuroantomic structures to be viewed in sharp detail. Recently, it has become possible to modify a conventional MRI scanner to study the brain's function as well. This new technique, called functional Magnetic Resonance Imaging (fMRI), has excited brain researchers for its several good features. The most commonly used fMRI technique is BOLD fMRI (Blood Oxygen Level Dependent fMRI). It is based on the principle that when a brain region is being used, arterial oxygenated blood will redistribute and increase to this area. Perfusion fMRI which can measure absolute regional blood flow has some limitations in that it takes several minutes to acquire information on a single slice of interest. It would be tedious obtainto enough images on this slice within a single session to make a statistical statement on a given subject. Diffusion weight Imaging is used to diagnosis the early post storke and to detecte the direction of myelin fibers tracts. MRI spectroscopy, an old fMRI technique, offers the capability of using MRI to noninvasively study tissue biochemistry which can determine the level of substance or energy metabolism. These techniques have been used widespreadly in neurology and neurosurgery. While there are currently no clinical indications for ordering any of these fMRI techniques, they hold considerable promise for unraveling the neurocircuitry and metabolic pathways of psychiatric disorders in the immediate future and in helping in psychiatric diagnosis and treatment planning down the road.