Systematic Artifact Reduction in Auditory fMRI

描述（由申请人提供）：使用回波平面成像（EPI）的功能磁共振成像（fMRI）会产生系统的混淆声噪声（“声成像噪声”），这可能会干扰与期望（声）刺激相关的皮质活动的fMRI测量。声学成像噪声不可避免地被听觉主体感知，导致包括皮层在内的整个听觉通路的神经元活动。声成像噪声的感知可以改变对所需刺激的感官感知，这种改变将影响生理活动并扭曲对所需刺激的血流动力学反应（HDR）的测量。最初针对听觉功能磁共振成像（fMRI）的方法被提出用于开发校正算法，该算法可用于校正与系统混淆相关的“理想”HDR（在没有混淆的情况下测量）的扭曲。修正算法的开发过程对功能磁共振成像社区产生了显著的好处，因为该过程可以应用于已知与功能磁共振成像数据获取相关的其他系统混淆。本研究的具体目的总结如下：目的1：获得1.5T时双频epi声成像噪声系统干扰下HDR的“理想”测量值。目标2：获得期望（声学）刺激下hdr的非理想测量值，通过系统混淆（声学成像噪声）的变化参数化，从而量化hdr之间的相互作用。目标3：开发校正算法，以补偿非理想HDR测量中存在的对期望（声学）刺激的失真，从而使所得的HDR估计值与没有系统混淆（声学成像噪声）时获得的估计值相似。相关性：在重复混淆（例如，与成像相关的声学噪声）存在的情况下进行的fMRI实验的定位准确性和检测灵敏度的提高，将允许更精确地区分皮层对刺激的反应，这些刺激可能只是细微的差异。这些好处将为检测到的活动的位置和范围提供更大的信心，显著影响人类大脑绘图，但也直接有利于术前绘图。

DESCRIPTION (provided by applicant): Functional magnetic resonance imaging (fMRI) using echo-planar imaging (EPI) results in generation of a systematic confound-acoustic noise ("acoustic imaging noise")-that can interfere with the fMRI measurement of cortical activity related to a desired (acoustic) stimulus. Acoustic imaging noise is unavoidably perceived by a hearing subject, leading to neuronal activity throughout the auditory pathway, including cortex. Perception of acoustic imaging noise can alter sensory perception of the desired stimulus-an alteration that will affect physiologic activity and distort measurement of the hemodynamic response (HDR) to the desired stimulus. Methods, initially directed at auditory fMRI, are proposed to develop correction algorithms that may be used to correct distortions of the "ideal" HDR (that measured in the absence of confound) associated with systematic confounds. Significant benefit to the fMRI community arises from the process by which the correction algorithm is developed, as the process may be applied to other systematic confounds known to be associated with acquisition of fMRI data. The specific aims of this research are summarized as follows: Aim 1: Obtain "ideal" measurements of the HDR to the systematic confound of acoustic imaging noise for blipped-EPI at 1.5T. Aim 2: Obtain non-ideal measurements of HDRs to a desired (acoustic) stimulus, parameterized by variations in the systematic confound (acoustic imaging noise), allowing quantification of interactions between the HDRs. Aim 3: Develop correction algorithms to compensate for distortions present in non-ideal HDR measurements to a desired (acoustic) stimulus, such that resulting HDR estimates resemble those which would be obtained in absence of the systematic confound (acoustic imaging noise). Relevance: Improvements in localization accuracy and detection sensitivity for fMRI experiments conducted in the presence of repeated confounds (e.g., acoustic noise associated with imaging) will allow more precise discrimination of cortical responses to stimuli that may differ only in a subtle fashion. These benefits will provide greater confidence in location and extent of detected activity, significantly impacting human brain mapping, but also directly benefiting efforts at pre-surgical mapping.