Quantitative assessment of auditory cortex responses induced by imager acoustic noise

作     者：Talavage, TM Edmister, WB Ledden, PJ Weisskoff, RM 

作者机构：Massachusetts Gen Hosp Dept Radiol NMR Ctr MGH Boston MA 02114 USA Harvard Univ MIT Div Hlth Sci & Technol Speech & Hearing Sci Program Cambridge MA 02139 USA Harvard Univ MIT Div Hlth Sci & Technol Med Engn Med Phys Program Cambridge MA 02139 USA Harvard Univ Sch Med MD PhD Program Boston MA USA 

出 版 物：《HUMAN BRAIN MAPPING》 (人脑图像描记)

年 卷 期：1999年第7卷第2期

页      面：79-88页

核心收录：

学科分类：0710[理学-生物学] 1001[医学-基础医学(可授医学、理学学位)] 07[理学] 1010[医学-医学技术（可授医学、理学学位）] 09[农学] 1009[医学-特种医学] 

基　　金：NIDA NIH HHS [P01DA09467-03] Funding Source: Medline NIDCD NIH HHS [P01DC00119, T32DC00038-04] Funding Source: Medline 

主　　题：fMRI pulse sequence brain mapping stimulus masking response suppression 

摘      要：A clustered volume acquisition functional MRT pulse sequence was modified to assess the response to the acoustic noise of echo-planar imaging in the auditory cortex and to determine whether it is possible to obtain data which is relatively free of acoustic contamination. The spatial location and strength (percent signal change) of cortical responses to the imager noise were examined by introducing extra gradient readouts, without slice excitation, to provide acoustic stimulation immediately prior to acquisition of a cerebral volume. The duration of acoustic stimulation was controlled by varying the number of extra gradient readouts. Slice acquisitions were clustered at the end of the repetition time (TR) period to prevent a response from being induced by the volume acquisition itself (Intra-Acquisition Response). The cerebral volumes were acquired using a long TR in order to limit the integration of the cortical response across volume acquisitions (Inter-Acquisition Response). Cortical responses were observed to be largest and most significant on the medial two-thirds of Heschl s gyrus, the location of primary auditory cortex. Mean signal changes induced by the imager noise were observed to be as high as 0.95%. A 2 sec delay prior to onset of the BOLD response was empirically determined. These results demonstrate that clustered volume acquisitions may be utilized for up to 2 sec of volume acquisition without inducing an appreciable Intra-Acquisition Response and can be used, with a sufficiently long TR, to provide data which are similarly free of any Inter-Acquisition Response. (C) 1999 Wiley-Liss, Inc.