QUANTITATIVE IMAGING OF CEREBRAL BLOOD FLOW AND OXYGEN CONSUMPTION

脑血流量和氧耗量可以用来研究 局部脑代谢和生理学。这个项目的目标是 是第一个开发无创磁共振(MR)方法的人 脑血流量和氧气消耗的定量成像，以及， 第二，应用这些方法研究局部大脑新陈代谢 以及精神分裂症患者的生理学。 正电子发射断层扫描(PET)方法使用放射性示踪剂 对脑血流量和氧耗进行成像。MR方法可以 使用MR可检测的“示踪器”提供相同的信息。然而，有一个 遵循时间进程的MR(和PET)方法的问题是什么 大脑中的示踪剂是需要良好的时间分辨率 会影响图像的空间分辨率。这个问题可能是 使用稳态示踪剂方法规避(在MR和PET中)。 “动脉自旋标记”技术提供了一种稳定的磁共振示踪器 脑血流成像方法。我们最初的自旋标记 对猫的实验证明了许多理论和技术上的 有问题。最重要的问题之一是对FAST的需求 动脉自旋标记图像的采集。我们现在已经牵涉到 此问题使用单次激发回波平面成像(EPI)，并已 将动脉自旋标记方法扩展到人类。初步研究 这表明，使用EPI版本的动脉自旋标记方法， 体素大小为？的定量脑血流图像抄送可以是 大约15分钟就能拿到。方法的优化， 使用更高的磁场强度和不同的数据采集 范例，应该会显著减少这种成像时间。

Cerebral blood flow and oxygen consumption can be used to investigate regional cerebral metabolism and physiology. The goals of this project are, first to develop non-invasive magnetic resonance (MR) approaches for quantitative imaging of cerebral blood flow and oxygen consumption, and, second, to apply these approaches to study regional cerebral metabolism and physiology in schizophrenic patients. Positron Emission Tomography (PET) approaches use radioactive tracers to image cerebral blood flow and oxygen consumption. MR approaches can provide the same information using MR-detectable "tracers". However, one of the problems with MR (and PET) approaches that follow the time-course of tracers in the brain is that the need for good time resolution compromises the spatial resolution of the image. This problem can be circumvented (in both MR and PET) using steady-state tracer approaches. "Arterial spin tagging" techniques provide a steady-state MR tracer approach for imaging cerebral blood flow. Our initial spin tagging experiments with cats demonstrated a number of theoretical and technical problems. One of the most important problems was the need for fast acquisition of the arterial spin tagging images. We have now involved this problem using single-shot echo planar imaging (EPI), and have extended the arterial spin tagging approach to humans. Initial studies indicate that, using EPI version of arterial spin tagging approaches, quantitative cerebral blood flow images with a voxel size of ? cc can be obtained in approximately 15 minutes. Optimization of the approach, using higher magnetic field strengths and different data acquisition paradigms, should reduce this imaging time significantly.