Morgan Victoria L, Gore John C
Department of Radiology, Vanderbilt University Institute of Imaging Science, Nashville, Tennessee 37232-2310, USA.
Hum Brain Mapp. 2009 Oct;30(10):3393-405. doi: 10.1002/hbm.20760.
When events occur spontaneously during the acquisition of a series of images, traditional modeling methods for detecting functional MRI activation detection cannot be employed. The two-dimensional temporal clustering algorithm, 2dTCA, has been shown to accurately detect random, transient activations in computer simulations without the use of known event timings. In this study we applied the 2dTCA technique to detect the timings and spatial locations of sparse, irregular, transient activations of the visual, auditory, and motor cortices in 12 normal controls. Experiments with one and two independent types of stimuli were employed. Event-related activation using known timing was compared with event-related activation using 2dTCA-detected timing in individuals and across groups. The 2dTCA algorithm detected the activation from all presented stimuli in every subject. When compared with block-design results using a measure of correlation between activation maps, no significant difference was found between the 2dTCA activation maps and the event-related maps using known timing across all subjects. Therefore, 2dTCA has the potential to be an accurate and more practical method for detection of spontaneous, transient events using fMRI.
当在获取一系列图像的过程中自发发生事件时，无法采用传统的用于检测功能磁共振成像激活的建模方法。二维时间聚类算法（2dTCA）已被证明在计算机模拟中无需使用已知事件时间就能准确检测随机、短暂的激活。在本研究中，我们应用2dTCA技术来检测12名正常对照者视觉、听觉和运动皮层的稀疏、不规则、短暂激活的时间和空间位置。采用了一种和两种独立类型刺激的实验。将使用已知时间的事件相关激活与使用2dTCA检测到的时间的事件相关激活在个体内和组间进行比较。2dTCA算法在每个受试者中检测到了所有呈现刺激的激活。当使用激活图之间的相关性度量与组块设计结果进行比较时，在所有受试者中，2dTCA激活图与使用已知时间的事件相关图之间未发现显著差异。因此，2dTCA有潜力成为一种使用功能磁共振成像检测自发、短暂事件的准确且更实用的方法。
