Center of Neurosurgery, Cologne University Hospital, 50924, Cologne, Germany; Department of Neurology, Cologne University Hospital, 50924, Cologne, Germany.
Center of Neurosurgery, Cologne University Hospital, 50924, Cologne, Germany.
Neuroimage. 2018 Aug 1;176:215-225. doi: 10.1016/j.neuroimage.2018.04.050. Epub 2018 Apr 25.
When using functional magnetic resonance imaging (fMRI) for mapping important language functions, a high test-retest reliability is mandatory, both in basic scientific research and for clinical applications. We, therefore, systematically tested the short- and long-term reliability of fMRI in a group of healthy subjects using a picture naming task and a sparse-sampling fMRI protocol. We hypothesized that test-retest reliability might be higher for (i) speech-related motor areas than for other language areas and for (ii) the short as compared to the long intersession interval. 16 right-handed subjects (mean age: 29 years) participated in three sessions separated by 2-6 (session 1 and 2, short-term) and 21-34 days (session 1 and 3, long-term). Subjects were asked to perform the same overt picture naming task in each fMRI session (50 black-white images per session). Reliability was tested using the following measures: (i) Euclidean distances (ED) between local activation maxima and Centers of Gravity (CoGs), (ii) overlap volumes and (iii) voxel-wise intraclass correlation coefficients (ICCs). Analyses were performed for three regions of interest which were chosen based on whole-brain group data: primary motor cortex (M1), superior temporal gyrus (STG) and inferior frontal gyrus (IFG). Our results revealed that the activation centers were highly reliable, independent of the time interval, ROI or hemisphere with significantly smaller ED for the local activation maxima (6.45 ± 1.36 mm) as compared to the CoGs (8.03 ± 2.01 mm). In contrast, the extent of activation revealed rather low reliability values with overlaps ranging from 24% (IFG) to 56% (STG). Here, the left hemisphere showed significantly higher overlap volumes than the right hemisphere. Although mean ICCs ranged between poor (ICC<0.5) and moderate (ICC 0.5-0.74) reliability, highly reliable voxels (ICC>0.75) were found for all ROIs. Voxel-wise reliability of the different ROIs was influenced by the intersession interval. Taken together, we could show that, despite of considerable ROI-dependent variations of the extent of activation over time, highly reliable centers of activation can be identified using an overt picture naming paradigm.
当使用功能磁共振成像（fMRI）进行重要语言功能的映射时，无论是在基础科学研究还是临床应用中，都需要具有较高的测试-重测可靠性。因此，我们使用图片命名任务和稀疏采样 fMRI 方案，在一组健康受试者中系统地测试了 fMRI 的短期和长期可靠性。我们假设测试-重测可靠性可能更高：（i）对于言语相关的运动区域，高于其他语言区域，（ii）对于较短的测试间隔，高于较长的测试间隔。16 名右利手受试者（平均年龄：29 岁）参加了三个间隔为 2-6 天（第 1 次和第 2 次，短期）和 21-34 天（第 1 次和第 3 次，长期）的 fMRI 测试。要求每个 fMRI 测试中受试者完成相同的外显图片命名任务（每次测试 50 张黑白图片）。使用以下指标测试可靠性：（i）局部激活最大值和重心（CoG）之间的欧几里得距离（ED），（ii）重叠体积和（iii）体素内类内相关系数（ICC）。分析基于全脑组数据选择了三个感兴趣区域（ROI）进行：初级运动皮层（M1）、上颞叶（STG）和下额前回（IFG）。我们的结果表明，激活中心具有高度可靠性，与时间间隔、ROI 或半球无关，局部激活最大值的 ED 明显小于 CoG（6.45 ± 1.36 mm 比 8.03 ± 2.01 mm）。相比之下，激活程度的可靠性值较低，重叠范围为 24%（IFG）至 56%（STG）。在这里，左半球的重叠体积明显高于右半球。虽然平均 ICC 值介于较差（ICC<0.5）和中等（ICC 0.5-0.74）之间，但所有 ROI 都发现了高度可靠的体素（ICC>0.75）。不同 ROI 的体素可靠性受到测试间隔的影响。总之，我们可以证明，尽管随着时间的推移，激活程度的 ROI 依赖性变化相当大，但使用外显图片命名范式可以识别出高度可靠的激活中心。
