1.0T下感觉运动皮层的激活：回波平面成像与梯度回波成像的比较
Activation of the sensorimotor cortex at 1.0 T: comparison of echo-planar and gradient-echo imaging.
作者信息
van der Kallen B F, van Erning L J, van Zuijlen M W, Merx H, Thijssen H O
机构信息
Department of Radiology, University Hospital Nijmegen, The Netherlands.
出版信息
AJNR Am J Neuroradiol. 1998 Jun-Jul;19(6):1099-104.
PURPOSE
The increasing demand for the clinical application of functional MR imaging raises the question of whether this technique can be routinely performed on 1.0-T MR scanners. To this end, we assessed the feasibility of functional MR imaging at 1.0 T.
METHODS
Healthy volunteers were scanned during the performance of a motor task. Functional data were acquired with echo-planar imaging (EPI) and with gradient-echo (GRE) and dual-echo GRE sequences. The signal intensity variations of the EPI and GRE sequences were compared, and the influence of inflow and blood oxygen level-dependent (BOLD) effects on the signal variations was assessed with the dual-echo GRE sequences.
RESULTS
In 11 of the 12 subjects we found activation in the primary motor cortex with both the GRE and EPI sequences. Active voxels had a significantly higher mean percentage of signal changes with the EPI sequence than with the GRE sequence (EPI: 1% to 6.1%, mean 2.4%; GRE: 1% to 4.5%, mean 1.9%). The EPI sequence was less sensitive to motion artifacts and enabled imaging of a larger brain volume in a shorter time. With a dual-echo sequence we found an increasing contribution of inflow effect with an increasing percentage of signal changes.
CONCLUSION
Functional MR imaging of the sensorimotor cortex can be routinely performed at 1.0 T.
目的
功能磁共振成像临床应用需求的不断增加引发了一个问题，即该技术能否在1.0-T磁共振扫描仪上常规进行。为此，我们评估了在1.0 T下进行功能磁共振成像的可行性。
方法
在健康志愿者执行运动任务期间对其进行扫描。使用回波平面成像（EPI）、梯度回波（GRE）和双回波GRE序列采集功能数据。比较EPI和GRE序列的信号强度变化，并使用双回波GRE序列评估流入和血氧水平依赖（BOLD）效应对信号变化的影响。
结果
在12名受试者中的11名中，我们发现GRE和EPI序列均在初级运动皮层中检测到激活。与GRE序列相比，EPI序列中激活体素的信号变化平均百分比显著更高（EPI：1%至6.1%，平均2.4%；GRE：1%至4.5%，平均1.9%）。EPI序列对运动伪影的敏感性较低，能够在更短的时间内对更大的脑体积进行成像。使用双回波序列，我们发现随着信号变化百分比的增加，流入效应的贡献也在增加。
结论
感觉运动皮层的功能磁共振成像可以在1.0 T下常规进行。
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