Chinese Acad Sci, Inst High Energy Phys, Key Lab Nucl Anal Techn, Beijing 100049, Peoples R China
; Chinese Acad Sci, Grad Sch, Beijing 100049, Peoples R China
; Gen Hosp Chinese Peoples Armed Police Forces, Beijing 100039, Peoples R China
; Capital Univ Med Sci, Xuanwu Hosp, Dept Radiol, Beijing 100053, Peoples R China
Temporal clustering analysis (TCA) has been proposed as a method for detecting the brain responses of a functional magnetic resonance imaging (fMRI) time series when the time and location of activation are completely unknown. But TCA is not suitable for treating the time series of the whole brain due to the existence of many inactive pixels. In theory, active pixels are located only in gray matter (GM). In this study, SPM2 was used to segment functional images into GM, white matter and cerebrospinal fluid, and only the pixels in GM were considered. Thus, most of inactive pixels are deleted, so that the sensitivity of TCA is greatly improved in the analysis of the whole brain. The same set of acupuncture fMRI data was treated using both conventional TCA and modified TCA (MTCA) for comparing their analytical ability. The results clearly show a significant improvement in the sensitivity achieved by MTCA. (C) 2007 Elsevier Inc. All rights reserved.