增强低场下脑功能磁共振成像显著性的研究

实现了基于低场0.35 T磁共振成像系统的大脑功能磁共振成像（functional Magnetic Resonance Imaging，fMRI）的研究. 基于质子密度加权的快速自旋回波(Turbo Spin Echo，TSE)图像，重点研究增强低场fMRI显著性的方法，目的在于提高低场fMRI的可用性. 结果表明：健康受试者在执行手动任务期间，大脑运动区的信号强度变化可以由基于血管外质子信号增强 (Signal Enhancement by Extravascular water Protons，EEP)的对比机制探测. 优化TSE序列参数能提高图像SNR和扫描速度，并在统计分析中增加外在屏蔽图像，可以有效地提高低场下fMRI研究结果的显著性.

Functional Magnetic Resonance Imaging at 0.35 T Using SEEP Contrast

Functional magnetic resonance imaging (fMRI) was performed on a low magnetic field strength (0.35 T) MRI system using a proton density weighted turbo spin-echo (TSE) imaging sequence. Healthy human volunteers performed a finger taping task, and the brain activations during the task were monitored. The results demonstrated that task-induced signal intensity changes in the motor area of the brain can be detected at 0.35 T with the contrast mechanism of signal enhancement by extravascular water protons (SEEP). It was also shown that the fMRI experiments at low field strength could be further improved by optimizing TSE parameters during data acquisition and adding a mask image during data processing.