Fan Xiaobing, Du Weiliang, MacEneaney Peter, Zamora Marta, Karczmar Gregory
Department of Radiology, University of Chicago, Chicago, Illinois 60637, USA.
J Magn Reson Imaging. 2002 Nov;16(5):547-52. doi: 10.1002/jmri.10193.
To acquire high spectral and spatial resolution (HiSS) MR images of the water resonance in rat brain, evaluate the lineshape of the water resonance in small voxels, and compare images derived from HiSS data with conventional images.
Spectroscopic images of rat brain were obtained at 4.7 Tesla using phase encoding gradients only. Spectral resolution in each voxel was approximately 8 Hz and bandwidth was 1,000 Hz. Spatial resolution was approximately 250 microns in 1-mm slices. Images were synthesized to show the water signal integral, peak height, linewidth, resonance frequency, and asymmetry.
Two or more resolved components of the water resonance were detected in approximately 14% +/- 6% of voxels in the brains of eight rats. The water resonances in approximately 20% +/- 10% of voxels (n = 8) were highly asymmetric. Images with intensity proportional to water signal peak height, T(2)*, or to selected components of the water resonance showed features that were not evident in conventional images.
The complexity of the water signal reflects the anatomy and physiology of the sub-voxelar environment, and may be a useful source of image contrast. HiSS imaging of brain provides accurate anatomic information, and may improve image contrast and delineation of subtle anatomic features.
获取大鼠脑内水共振的高光谱和空间分辨率（HiSS）磁共振图像，评估小体素内水共振的线形，并将HiSS数据生成的图像与传统图像进行比较。
仅使用相位编码梯度在4.7特斯拉下获取大鼠脑的光谱图像。每个体素的光谱分辨率约为8赫兹，带宽为1000赫兹。在1毫米厚的切片中，空间分辨率约为250微米。合成图像以显示水信号积分、峰高、线宽、共振频率和不对称性。
在8只大鼠脑内约14%±6%的体素中检测到两个或更多分辨出的水共振成分。在约20%±10%的体素（n = 8）中，水共振高度不对称。强度与水信号峰高、T(2)*或水共振选定成分成比例的图像显示出传统图像中不明显的特征。
水信号的复杂性反映了亚体素环境的解剖结构和生理状态，可能是图像对比度的一个有用来源。脑的HiSS成像提供了准确的解剖信息，并可能改善图像对比度和细微解剖特征的描绘。
