基于低频振幅算法的血氧水平依赖功能磁共振成像在无灶性癫痫中的应用

Application of amplitude of low-frequency fluctuation in non-lesional epilepsy： a blood oxygenation level dependent functional MRI study

目的采用基于低频振幅算法的血氧水平依赖功能磁共振成像技术，探讨无灶性癫痫脑活动的神经机制及其意义。方法运用功能性磁共振成像技术观察安徽医科大学附属省立医院自2010年9月至2011年3月收治的16例无灶性癫痫患者和同期招募的15名健康对照者脑血氧水平依赖信号的改变；收集其静息态数据，然后运用低频振幅算法对数据进行分析，得到每个受试者的低频振幅统计图，观察无灶性癫痫患者相对于健康对照者低频振荡幅度（ALFF）增高和减弱的区域。结果无灶性癫痫组和健康对照组相比AulF增强的脑区分布在右侧颞叶fMNI坐标分别为15，-90，-21）、内侧额叶（0，24，-24）、腹侧前扣带回（-12，30，27）及右侧小脑半球（-51，-57，-4）；而ALFF减弱的脑区分布在左侧小脑半球及相邻后缘枕叶（-48，-15，39）、后扣带回（60，-21，33）及楔前叶（-6，-54，66）。结论无灶性癫痫患者静息状态下表现出异常的脑功能活动方式，ALFF升高的脑区反映了大脑对癫痫活动的产生、传播等易化作用，表明了癫痫的高活动；而ALFF减低的脑区则反映了大脑对癫痫活动的抑制。

Objective To study the changes of amplitude of low-frequency fluctuation （ALFF） in blood oxygenation level dependent functional MRI （BOLD-fMRI） in non-lesional epilepsy （NLE）, and discuss its underlying neurophysiological mechanism. Methods The BOLD-fMRI data of 16 patients with NLE and 15 normal volunteers were analyzed by ALFF. The amplitude of the blood oxygenation level dependent activation of the resting state brain was investigated. The brain structures showing increased and decreased ALFF in NLE patients were demonstrated by comparing to normal subjects with 2-sample t-test with threshold of P〈0.05. Results As compared with those in normal subjects, the regions showing increased ALFF in NLE patients were distributed in the right temporal lobe （Montreal Neurological Institute [MNI] coordinates： x=15, y=-90, z=21）, medial frontal lobe （MNI coordinates： 0, 24, -24）, ventral anterior cingulated （MNI coordinates： -12, 30, 27） and right cerebellar hemisphere （MNI coordinates： -51, -57, -4）; while the regions showing decreased ALFF covered the areas of the left cerebellar hemisphere （MNI coordinates： -48, -15, 39）, posterior cingulum gyms （MNI coordinates： 60, -21, 33） and precuneus （MNI coordinates： -6, -54, 66）. Conclusion NLE patients show abnormal brain functional organization in resting state; the increased ALFF is considered to be the facilitation such as epileptic activity generation and propagation, while the decreased ALFF might be considered as the functional inhibition in these regions.