Lu Hanbing, Mazaheri Yousef, Zhang Rongyan, Jesmanowicz Andrzej, Hyde James S
Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
Magn Reson Med. 2003 Dec;50(6):1215-22. doi: 10.1002/mrm.10655.
A multishot partial-k-space EPI technique is presented and validated by fMRI at high spatial resolution. High-resolution phase maps corrected by phase-encoded reference scans have less off-resonance effects. Phantom studies demonstrate that this method can substantially improve partial-k-space EPI image formation. BOLD fMRI at submillimeter spatial resolution (156 x 156 x 2000 microm(3), 0.049 microl) was achieved in a rat whisker barrel stimulation model using this technique. The study included eight rats, five of which were administered an intravascular contrast agent (monocrystalline iron oxide nanocolloid (MION)) after the BOLD experiments. In two rats the highest BOLD responses were in the deep layers (IV-VI), and in six rats the highest responses were on the surface and in the deep cortical layers. Most of the pixels that exhibited high BOLD responses had high blood volume weightings. The benefits of this technique are expected to increase for high-resolution fMRI at higher magnetic fields, where T(2) (*) is shorter.
本文介绍了一种多激发部分k空间EPI技术，并通过功能磁共振成像（fMRI）在高空间分辨率下进行了验证。通过相位编码参考扫描校正的高分辨率相位图具有较小的失谐效应。模型研究表明，该方法可显著改善部分k空间EPI图像的形成。使用该技术在大鼠胡须桶状刺激模型中实现了亚毫米空间分辨率（156×156×2000微米³，0.049微升）的血氧水平依赖性功能磁共振成像（BOLD fMRI）。该研究包括8只大鼠，其中5只在BOLD实验后给予血管内造影剂（单晶氧化铁纳米胶体（MION））。在2只大鼠中，最高的BOLD反应出现在深层（IV-VI层），在6只大鼠中，最高反应出现在表面和深层皮质层。大多数表现出高BOLD反应的像素具有高血容量权重。预计在更高磁场下进行高分辨率fMRI时，该技术的优势将更加明显，因为在更高磁场下T2*更短。
