title: Complementary Detection of Multiple Electrical Sources in Tissue Using Acoustoelectric Effects.
abstract: Accurate 3-D mapping of multiple bioelectric sources in nerve fibers with high spatial resolution is challenging for the diagnosis and treatment of a variety of neural abnormalities. Ultrasound current source density imaging exploits the acoustoelectric (AE) effect, an interaction between electrical current and acoustic pressure waves propagating through a conducting material, and has distinct advantages over conventional electrophysiology (i.e., without ultrasound) for mapping electrical current flow in tissue. Ultrasound current source density imaging and two complementary Wheatstone bridge circuits were used to simultaneously detect two separate current flows induced in tissue phantoms. It has been found that the addition and subtraction of AE signals acquired by two circuits are independent components, regardless of whether the two sources are positioned at the same or different depths. In the ultrasound field, the AE signal from the bridge circuits is stronger, with a higher signal-to-noise ratio, than without a bridge circuit. Both experimental and simulated AE images depend on the magnitude and direction of the current, as well as the geometry (shape and thickness) and location of the current sources in the ultrasound field (2.25-MHz transducer). The experimental results are consistent with simulations consisting of multiple current sources. Real-time 3-D ultrasound current source density images of multiple current flows co-registered with convention pulse echo ultrasound potentially facilitate monitoring of neurologic disorders.
authors.affiliation: Department of Electrical Engineering and Computer Science, Texas A&M University-Kingsville, Kingsville, Texas, USA. Electronic address: zhaohui.wang@tamuk.edu.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Electrical Engineering and Computer Science, Texas A&M University-Kingsville, Kingsville, Texas, USA.
authors.forename: Rajab
authors.initials: R
authors.lastname: Challoo
authors.affiliation: Department of Biomedical Engineering, School of Medical Engineering, Hefei University of Technology, Hefei, Anhui, China.
authors.forename: Hu
authors.initials: H
authors.lastname: Peng
authors.affiliation: Department of Electrical Engineering and Computer Science, Texas A&M University-Kingsville, Kingsville, Texas, USA.
authors.forename: Chung S
authors.initials: CS
authors.lastname: Leung
authors.affiliation: Department of Optical Sciences, University of Arizona, Tucson, Arizona, USA; Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA; Department of Medical Imaging, University of Arizona, Tucson, Arizona, USA.
authors.forename: Russell S
authors.initials: RS
authors.lastname: Witte
mesh_terms: D000162:Acoustics; D003198:Computer Simulation; D004560:Electricity; D055724:Electrophysiological Phenomena; D021621:Imaging, Three-Dimensional / Q000379:methods*; D019047:Phantoms, Imaging; D012815:Signal Processing, Computer-Assisted; D059629:Signal-To-Noise Ratio; D014463:Ultrasonography / Q000379:methods*
keywords: Acoustoelectric; Bioelectric; Electroencephalography; Electrophysiology; Mapping