Cutrer F M, O'Donnell A, Sanchez del Rio M
Partners Headache Center, Department of Neurology, Massachusetts General Hospital, Boston, 02129, USA.
Neurology. 2000;55(9 Suppl 2):S36-45.
Research into migraine pathophysiology has been hampered by the episodic nature and unpredictable onset of migraine attacks. Recently, newer imaging techniques have been providing noninvasive methods of studying metabolism and hemodynamics in the brains of migraineurs during and between acute attacks. 133Xe blood flow techniques, transcranial Doppler, and SPECT have all been employed to investigate hemodynamic changes during migraine aura. PET has been useful in the study of migraine without aura, with findings of increased blood flow related to pain in cortical areas and in the medial brainstem. Currently, three functional MRI imaging techniques are being used in migraine research. Diffusion-weighted imaging has shown normal findings in measures of the ability of neurons to maintain osmotic gradients. Studies using perfusion-weighted imaging have shown alterations in relative cerebral blood flow (CBF), relative cerebral blood volume, and mean transit time during migraine visual aura. The blood oxygen level-dependent technique can supply information related to neuronal activation during acute migraine aura. MRS has been used with mixed success to look for evidence of abnormal energy metabolism in the brains of migraineurs. Magnetoencephalography studies support the presence of a spreading depression-like phenomenon in migraine with aura. Two groups have used transcranial magnetic stimulation to assess whether neurons in the occipital cortex are hyperexcitable, predisposing patients to develop aura symptoms. Despite conflicting findings, migraine with visual aura appears to be generally associated with transient decreases in regional CBF.
偏头痛发作的间歇性和不可预测性阻碍了对其病理生理学的研究。最近，更新的成像技术为研究偏头痛患者在急性发作期间及发作间期大脑中的代谢和血流动力学提供了非侵入性方法。133Xe血流技术、经颅多普勒和单光子发射计算机断层扫描（SPECT）都已用于研究偏头痛先兆期间的血流动力学变化。正电子发射断层扫描（PET）在无先兆偏头痛的研究中很有用，研究发现与皮质区域和中脑干部位疼痛相关的血流增加。目前，三种功能磁共振成像技术正在用于偏头痛研究。扩散加权成像在测量神经元维持渗透梯度能力方面显示正常结果。使用灌注加权成像的研究表明，在偏头痛视觉先兆期间，相对脑血流量（CBF）、相对脑血容量和平均通过时间发生了改变。血氧水平依赖技术可以提供与急性偏头痛先兆期间神经元激活相关的信息。磁共振波谱（MRS）用于寻找偏头痛患者大脑中能量代谢异常证据的结果喜忧参半。脑磁图研究支持有先兆偏头痛中存在类似扩散性抑制的现象。两组研究人员使用经颅磁刺激来评估枕叶皮质中的神经元是否过度兴奋，从而使患者易出现先兆症状。尽管研究结果相互矛盾，但有视觉先兆的偏头痛似乎通常与局部脑血流量的短暂减少有关。
