QUANTITATIVE IMAGING OF CEREBRAL BLOOD FLOW AND OXYGEN CONSUMPTION

脑血流量和耗氧量可用于调查 局部脑代谢和生理学。 本项目的目标 是，首先开发非侵入性磁共振（MR）方法， 脑血流和氧消耗的定量成像，以及， 第二，应用这些方法研究局部脑代谢 精神分裂症患者的心理和生理学。 正电子发射断层扫描（PET）方法使用放射性示踪剂， 成像脑血流和氧消耗。 MR方法可以 使用MR可检测的“示踪剂”提供相同的信息。 不过有一 MR（和PET）方法遵循时间过程的问题 大脑中示踪剂的重要性在于， 损害了图像的空间分辨率。 这个问题可以 使用稳态示踪剂方法规避（在MR和PET中）。 “动脉自旋标记”技术提供了稳态MR示踪剂 脑血流成像的方法。 我们最初的自旋标记 猫的实验证明了一些理论和技术 问题 最重要的问题之一是需要快速 动脉自旋标记图像的采集。 我们现在已经涉及到 使用单次激发回波平面成像（EPI）解决这个问题， 将动脉自旋标记方法扩展到人类。 初步研究 这表明，使用EPI版本动脉自旋标记方法， 定量脑血流图像的体素大小？cc可以 在大约15分钟内获得。 方法的优化， 使用更高的磁场强度和不同的数据采集 范例，应该减少这种成像时间显着。

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.