Senda M, Ishii K, Oda K, Sadato N, Kawashima R, Sugiura M, Kanno I, Ardekani B, Minoshima S, Tatsumi I
Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Tokyo, 173-0015, Japan.
Neuroimage. 1998 Oct;8(3):283-301. doi: 10.1006/nimg.1998.0370.
We have created images of z value, error, and variation components for a PET activation study using various ANOVA designs and anatomical standardization methods. Data were acquired in four PET centers. In each center, CBF was measured on six normal male subjects under resting and covert verb generation, three times for each. The images were anatomically standardized with LINEAR transformation, SPM (Ver. 95), HBA (Karolinska/Tohoku), or MICHIGAN (Minoshima). ANOVA was performed pixel by pixel to compute t (and z) for the task main effect (Verb vs Rest) in four different designs: (i) two way (subject and task) (2W), (ii) two-way with interaction (2WI), (iii) subject considered a random factor (2WI-MX), and (iv) three-way (subject, task, and replication) (3W). A large area extending from the Broca to the left premotor cortex was activated. The localization of the highest peak depended both on the anatomical standardization and on the ANOVA design, the variation ranging 3-4 cm. Smoothing reduced the variation while erasing possible subfoci. The z images of 2W, 2WI, and 3W looked alike, whereas 2WI-MX presented lower peak z values. SPM tended to present higher z values than the other methods. The error was high in the gray and low in the white matter. The root mean square for the subject effect was high on the border of gray matter especially in LINEAR and HBA, revealing intersubject mismatch in the gray matter distribution. The root mean square for the subject-by-task interaction effect revealed individual variation in activation.
我们使用各种方差分析设计和解剖标准化方法，为一项正电子发射断层扫描（PET）激活研究创建了z值、误差和变异成分的图像。数据在四个PET中心采集。在每个中心，对六名正常男性受试者在静息和隐蔽动词生成状态下测量脑血流量（CBF），每种状态测量三次。图像通过线性变换、统计参数映射（SPM，版本95）、赫尔辛基大脑模板（HBA，卡罗林斯卡/东北大学）或密歇根模板（Minoshima）进行解剖标准化。逐像素进行方差分析，以计算四种不同设计中任务主效应（动词生成与静息）的t值（和z值）：（i）双向（受试者和任务）（2W），（ii）具有交互作用的双向（2WI），（iii）将受试者视为随机因素（2WI-MX），以及（iv）三向（受试者、任务和重复）（3W）。从布洛卡区延伸至左侧运动前区皮质的大片区域被激活。最高峰的定位既取决于解剖标准化，也取决于方差分析设计，变化范围为3 - 4厘米。平滑处理减少了变化，同时消除了可能的亚灶。2W、2WI和3W的z图像看起来相似，而2WI-MX呈现较低的峰值z值。与其他方法相比，SPM往往呈现更高的z值。灰质中的误差较高，白质中的误差较低。受试者效应的均方根在灰质边界处较高，尤其是在线性变换和HBA方法中，这表明灰质分布存在受试者间不匹配。受试者与任务交互效应的均方根揭示了激活的个体差异。
