Créac'h C, Henry P, Caillé J M, Allard M
Service de Neuroradiologie/Neurologie CHU de Bordeaux, France.
AJNR Am J Neuroradiol. 2000 Sep;21(8):1402-6.
Most studies concerning imaging of pain processing have used thermal, chemical, or electrical nociceptive stimulation. The aim of the present study was to determine the cortical representation of mechanical pain. For this, using functional MR (fMR) imaging at 1.5 T, we compared activation patterns during painful and nonpainful tonic mechanical stimulation in healthy volunteers.
Eleven right-handed subjects ranging in age from 21 to 46 years underwent gradient-echo echo-planar fMR imaging while quantified tonic pressure was applied to the first metacarpophalangeal joint. Imaging parameters were 3,000/60 (TR/TE) with a 5-mm section thickness in a 7.30-minute sequence with 2 x 90 seconds of painful stimulation interleaved with 3 x 90 seconds of nonpainful stimulation. Functional images were processed using dedicated IDL software.
Mechanical tonic nociceptive pressure was associated with activation of the primary somatosensory cortex contralateral to the hand stimulated and variable, often bilateral activation of the secondary somatosensory, temporal, anterior and posterior cingulate, insular, and prefrontal cortexes. Thalamic activation was inconsistent and always contralateral to stimulation.
The interindividual variability found in this fMR imaging study calls for repetitive single-subject analysis or more extensive studies of large groups of patients. Either may be based on fMR imaging analysis of brain activation after tonic mechanically induced pain, which leads to deep pain sensation similar to patients' painful sensations most commonly encountered in clinical practice.
大多数关于疼痛处理成像的研究都使用了热、化学或电伤害性刺激。本研究的目的是确定机械性疼痛的皮质表征。为此，我们使用1.5T的功能磁共振成像（fMR），比较了健康志愿者在疼痛和非疼痛性持续性机械刺激过程中的激活模式。
11名年龄在21至46岁之间的右利手受试者接受了梯度回波平面回波fMR成像，同时对第一掌指关节施加定量的持续性压力。成像参数为3000/60（TR/TE），层厚5mm，扫描序列持续7.30分钟，其中包含2次每次90秒的疼痛刺激，与3次每次90秒的非疼痛刺激交替进行。功能图像使用专门的IDL软件进行处理。
机械性持续性伤害性压力与受刺激手对侧的初级体感皮层激活相关，并且在次级体感皮层、颞叶、前扣带回和后扣带回、岛叶和前额叶皮层出现了可变的、通常为双侧的激活。丘脑激活不一致，且总是与刺激对侧。
本fMR成像研究中发现的个体间变异性要求进行重复的单受试者分析或对大量患者进行更广泛的研究。两者都可以基于对持续性机械诱发疼痛后大脑激活的fMR成像分析，这种疼痛会导致类似于临床实践中最常见的患者疼痛感觉的深部疼痛感觉。
