Harrington G S, Buonocore M H, Farias S Tomaszewski
Department of Radiology, University of California at Davis, Davis, CA, USA.
AJNR Am J Neuroradiol. 2006 Apr;27(4):938-44.
The purpose of this study was to examine the reproducibility of functional MR imaging (fMRI) activation (volume and laterality) within both inferior frontal and temporoparietal regions of interest for both receptive and expressive language tasks.
Ten healthy volunteers participated in fMRI experiments for 6 language tasks: verb generation, confrontation naming, semantic decision making, visual sentence comprehension, auditory sentence comprehension, and story listening. Each subject was scanned during 2 separate sessions separated by a minimum of 4 weeks. Laterality of activation was defined by laterality indices (LIs), which were calculated by 2 methods: one method based on the measured volume of activation and the other method based on the F statistic of the activation. Reproducibility was calculated by using concurrence ratios for the volume of activation (R(overlap), R(volume)) and test-retest correlation for LIs.
All tasks generated reproducible LIs within at least one of the regions of interest, but verb generation produced the highest test-retest correlations (r = 0.99) within both regions of interest. Verb generation was associated with the highest average concurrence ratios within the inferior frontal region of interest (R(overlap) = 45.2; R(volume) = 70.9). In general, the concurrence ratios were lower within the temporoparietal region of interest compared with the inferior frontal region of interest. LIs calculated with F statistics were more reproducible than the LIs calculated by activation volume.
fMRI is able to provide reproducible LIs in both inferior frontal and temporoparietal regions for assessing hemispheric dominance in language processing. The volume of activation, especially within the temporoparietal regions, is less reproducible than the laterality of activation, so the former should be used with caution.
本研究旨在检测功能磁共振成像（fMRI）激活（体积和偏侧性）在额下回和颞顶叶感兴趣区内对于接受性和表达性语言任务的可重复性。
10名健康志愿者参与了针对6种语言任务的fMRI实验：动词生成、对物命名、语义决策、视觉句子理解、听觉句子理解和故事聆听。每位受试者在2个单独的扫描时段接受扫描，间隔至少4周。激活的偏侧性由偏侧性指数（LI）定义，其通过2种方法计算：一种基于测量的激活体积，另一种基于激活的F统计量。通过使用激活体积的一致性比率（R(重叠)，R(体积)）和LI的重测相关性来计算可重复性。
所有任务在至少一个感兴趣区内产生了可重复的LI，但动词生成在两个感兴趣区内产生了最高的重测相关性（r = 0.99）。动词生成与额下回感兴趣区内的最高平均一致性比率相关（R(重叠) = 45.2；R(体积) = 70.9）。总体而言，与额下回感兴趣区相比，颞顶叶感兴趣区内的一致性比率较低。用F统计量计算的LI比用激活体积计算的LI更具可重复性。
fMRI能够在额下回和颞顶叶区域提供可重复的LI，用于评估语言处理中的半球优势。激活体积，尤其是在颞顶叶区域内，比激活的偏侧性更不可重复，因此应谨慎使用前者。
