Characterizing Response to Elemental Unit of Acoustic Imaging Noise: An fMRI Study

• Published in: IEEE transactions on biomedical engineering 2009-07, Vol.56 (7), p.1919-1928
• Main Authors: Tamer, Gregory G., Luh, Wen-Ming, Talavage, Thomas M.
• Format: Article
• Language: English
• Subjects: Acoustic imaging; Acoustic noise; Acoustic Stimulation - adverse effects; Acoustics; Adult; Amplitudes; Auditory Cortex - physiology; auditory system; biomedical image processing; Brain Mapping; Cortexes; Female; Foundations; Hemodynamic responses; Hemodynamics; Humans; Image analysis; Image Processing, Computer-Assisted - methods; Magnetic analysis; Magnetic noise; Magnetic properties; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Marketing; Mathematical models; modeling; Models, Neurological; Models, Statistical; Noise; Noise level; Phantoms, Imaging; Time series analysis
• ISSN: 0018-9294; 1558-2531
• DOI: 10.1109/TBME.2009.2016573

Acoustic imaging noise produced during functional magnetic resonance imaging (fMRI) studies can hinder auditory fMRI research analysis by altering the properties of the acquired time-series data. Acoustic imaging noise can be especially confounding when estimating the time course of the hemodynamic response (HDR) in auditory event-related fMRI (fMRI) experiments. This study is motivated by the desire to establish a baseline function that can serve not only as a comparison to other quantities of acoustic imaging noise for determining how detrimental is one's experimental noise, but also as a foundation for a model that compensates for the response to acoustic imaging noise. Therefore, the amplitude and spatial extent of the HDR to the elemental unit of acoustic imaging noise (i.e., a single ping) associated with echoplanar acquisition were characterized and modeled. Results from this fMRI study at 1.5 T indicate that the group-averaged HDR in left and right auditory cortex to acoustic imaging noise (duration of 46 ms) has an estimated peak magnitude of 0.29% (right) to 0.48% (left) signal change from baseline, peaks between 3 and 5 s after stimulus presentation, and returns to baseline and remains within the noise range approximately 8 s after stimulus presentation.