功能磁共振成像与H2 15O正电子发射断层扫描在初级视觉皮层刺激中的比较。
Comparison of functional MR and H2 15O positron emission tomography in stimulation of the primary visual cortex.
作者信息
Kraut M A, Marenco S, Soher B J, Wong D F, Bryan R N
机构信息
Department of Radiology, Johns Hopkins University, Baltimore, Md 21287-2182, USA.
出版信息
AJNR Am J Neuroradiol. 1995 Nov-Dec;16(10):2101-7.
PURPOSE
To locate spoiled gradient-echo functional MR signal changes in relation to brain parenchyma.
METHODS
The region of the primary visual cortex was evaluated using functional MR and H2 15O positron emission tomography in each of six male subjects who were being visually stimulated by means of red light-emitting diode flash goggles.
RESULTS
The positron emission tomography technique demonstrated substantially greater relative signal change with visual stimulation than did the functional MR technique. Furthermore, the functional MR signal changes were concentrated in loci around the periphery of brain parenchyma exhibiting increased radiotracer activity, as opposed to being collocated.
CONCLUSIONS
Signal changes found using functional MR based on gradient-echo techniques reflect primarily phenomena occurring within small veins and underrepresent activity intrinsic to brain parenchyma, thus introducing potential inaccuracies in locating regions of activated brain tissue. Positron emission tomography, however, directly measures changes in metabolically related activity within the parenchyma.
目的
确定 spoiled 梯度回波功能磁共振信号变化相对于脑实质的位置。
方法
对六名男性受试者中的每一位，使用功能磁共振成像和 H2 15O 正电子发射断层扫描技术评估初级视觉皮层区域，这些受试者通过红色发光二极管闪光护目镜接受视觉刺激。
结果
与功能磁共振技术相比，正电子发射断层扫描技术在视觉刺激下显示出明显更大的相对信号变化。此外，功能磁共振信号变化集中在脑实质周边表现出放射性示踪剂活性增加的位点周围，而不是与之并置。
结论
基于梯度回波技术使用功能磁共振发现的信号变化主要反映了小静脉内发生的现象，并且不能充分代表脑实质固有的活动，从而在定位激活的脑组织区域时引入潜在的不准确因素。然而，正电子发射断层扫描直接测量实质内与代谢相关的活动变化。
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