Menon R S, Goodyear B G
Department of Medical Biophysics, The University of Western Ontario, London, Canada.
Magn Reson Med. 1999 Feb;41(2):230-5. doi: 10.1002/(sici)1522-2594(199902)41:2<230::aid-mrm3>3.0.co;2-o.
Using multislice segmented echoplanar imaging at 4 T, we have measured an upper bound to the cortical vasculature point-spread function (PSF) using functional magnetic resonance imaging (fMRI) in humans. Our experiments demonstrate that cortical subunits that are approximately 700 microm apart can be resolved using the early part of the hyperoxygenation phase of the blood oxygenation level-dependent (BOLD) effect. This was accomplished using brief (4 sec) single trials of monocular and binocular stimulation of ocular dominance columns in human primary visual cortex. The data suggest that at even higher magnetic fields, the cortical vasculature PSF may be limited by the extent and nature of horizontal connections and not signal-to-noise ratio.
我们使用4T的多层分段回波平面成像技术，通过功能磁共振成像（fMRI）测量了人类皮质脉管系统点扩散函数（PSF）的上限。我们的实验表明，利用血氧水平依赖（BOLD）效应的高氧合阶段早期，可以分辨相距约700微米的皮质亚单位。这是通过对人类初级视觉皮层的眼优势柱进行短暂（4秒）单眼和双眼刺激的单次试验来实现的。数据表明，在更高的磁场下，皮质脉管系统PSF可能受水平连接的范围和性质限制，而非信噪比。
