Imaging current flow in lobster nerve cord using the acoustoelectric effect

Witte, Russell S.; Olafsson, Ragnar; Huang, Sheng Wen; O’Donnell, Matthew

doi:10.1063/1.2724901

Cited by 58 publications

(63 citation statements)

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“…2(c)), consistent with theory and previous studies. [4][5][6][7][8][9][10] Also, a gradual decrease in the AE signal was observed on distant recording electrodes ( Fig. 2(d)) relative to the ground reference.…”

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confidence: 99%

“…This complements earlier studies reporting that UCSDI has sufficient sensitivity to detect biologically relevant current in cardiac and neural tissue at safe levels of acoustic exposure for imaging. 4,5 The mechanical index (MI) is typically employed to quantify acoustic exposure for short ultrasound pulses at a low duty cycle. MI is defined as P neg /Hf c , where P neg is peak negative pressure and f c is center frequency in MHz.…”

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confidence: 99%

“…3 Ultrasound current source density imaging (UCSDI) has been proposed as a complement and possible alternative to traditional mapping of electrophysiological signals. [4][5][6][7][8][9][10][11] UCSDI exploits the acoustoelectric effect (AE), an interaction between pressure and current, to map electric field distributions while scanning a focused ultrasound beam. A previous study in the rabbit heart demonstrated that UCSDI has sufficient sensitivity to map the cardiac activation wave.…”

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Four-dimensional ultrasound current source density imaging of a dipole field

Wang

Olafsson

Ingram

et al. 2011

Applied Physics Letters

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Ultrasound current source density imaging (UCSDI) potentially transforms conventional electrical mapping of excitable organs, such as the brain and heart. For this study, we demonstrate volume imaging of a time-varying current field by scanning a focused ultrasound beam and detecting the acoustoelectric (AE) interaction signal. A pair of electrodes produced an alternating current distribution in a special imaging chamber filled with a 0.9% NaCl solution. A pulsed 1 MHz ultrasound beam was scanned near the source and sink, while the AE signal was detected on remote recording electrodes, resulting in time-lapsed volume movies of the alternating current distribution. Electrical mapping helps identify abnormal electric pathways in the heart (i.e., arrhythmias) and brain (i.e., epileptic seizures) during treatment.1,2 This invasive procedure requires assumptions for reconstructing the current distribution, has limited spatial resolution, and is sensitive to registration errors.3 Ultrasound current source density imaging (UCSDI) has been proposed as a complement and possible alternative to traditional mapping of electrophysiological signals.4-11 UCSDI exploits the acoustoelectric effect (AE), an interaction between pressure and current, to map electric field distributions while scanning a focused ultrasound beam. A previous study in the rabbit heart demonstrated that UCSDI has sufficient sensitivity to map the cardiac activation wave. 4 Potential advantages of UCSDI include 1) remote detection of current with a spatial resolution determined by the size of the ultrasound focus (<5 mm 3 ); 2) volume images of current flow and biopotentials with as few as one electrode and ground without major assumptions regarding conductivity; 3) automatic coregistration of UCSDI with pulse echo (PE) ultrasound for simultaneously portraying current flow with anatomy. This study demonstrates volume imaging of a timevarying current field produced by scanning an ultrasound beam and detecting the generated AE signal.UCSDI is based on reciprocal theory. 4,6,11 In an electric field produced from a distributed current source J I ¼ J I (x, y, z; t s ) changing in physiologic time t s , the voltage V i measured by lead i at coordinate x 0 , y 0 , z 0 can be expressed in four dimensions under the assumption of far field detection of the AE signal. If an ultrasound beam is centered at C(x 0 , y 0 , z 0 ), then any point (x, y, z) in the pressure field can be represented in the electric field as (x þ x 0 , y þ y 0 , z þ z 0 ). The induced AE voltage (V AE ) detected by two distant electrodes can be represented bywith pressure pulse amplitude P 0 , interaction constant K I , resistivity q 0 , current distribution of detector J i L (x, y, z), ultrasound beam pattern b(x, y, z) defined with the transducer at the origin, speed of sound c, ultrasound pulse waveform a(t-z/c), and fast ultrasound time t. The instantaneous local field potential is reconstructed by demodulating (or basebanding) the AE signal. The current density J I of the dipole is modele...

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Four-dimensional ultrasound current source density imaging of a dipole field

Wang

Olafsson

Ingram

et al. 2011

Applied Physics Letters

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“…Acousto-Electric Interaction has been suggested as a technique for imaging the electrical conductivity distribution of biological tissues with a resolution typical of ultrasound [1], [2], [3], [4]. It has been shown that breast tumors have characteristic electrical properties different from those of healthy tissue [5].…”

Section: Introductionmentioning

confidence: 99%

Experimental setup for developing acousto-electric interaction imaging

Gendron

Guardo

Bertrand

2009

2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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Acousto-Electric Interaction (AEI) is a physical phenomenon identified in the literature as potentially useful for imaging the electrical conductivity of biological tissues. AEI could lead to a non-invasive technique for detecting breast tumors, since the conductivity of pathological tissues differs significantly from the conductivity of healthy breast tissues. Applying AEI to image heterogeneous structures of the size of the breast represents a major technical challenge. We present in this paper an experimental setup designed to address the various instrumentation issues of AEI. Tests results are presented showing the ultrasonic vibration potential (also known as the Debye effect) and the AEI signals. A preliminary analysis of the AEI signal we recorded suggests that cavitation effects can be measured with this technique.

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“…7 Influential in the research of acousto-electric interaction signal in the recent years, has been a group of American researchers at the University of Michigan, that have performed several investigations on the AEI signal and the possibility of using the signal to map biological current. 2,[8][9][10][11][12][13][14][15][16][17] Several more studies have been performed for further investigations and improvements of measurements and setup. 18 Also our group has made some investigations and come up with a potentially useful application for denervated muscles.…”

Section: (2)mentioning

confidence: 99%

Application of acoustic-electric interaction for neuro-muscular activity mapping: A review

Helgason

Gunnlaugsdottir

2015

Eur J Transl Myol

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Acousto-electric interaction signal (AEI signal) resulting from interaction of acoustic pressure wave and electrical current field has received recent attention in biomedical field for detection and registration of bioelectrical current. The signal is of very small value and brings about several challenges when detecting it. Several observations on the AEI signal have been done in saline solution and on nerves and tissues under controlled condition that give optimistic indication for its utilization. Ultrasound Current Source Density Imaging (UCSDI) has been introduced, that uses the AEI signal to image the current distribution. This review provides an overview of the investigations on the AEI signal and USCDI imaging that has been made, their results and several considerations on the limitations and future possibilities on using the acousto-electric interaction signal.

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Imaging current flow in lobster nerve cord using the acoustoelectric effect

Cited by 58 publications

References 9 publications

Four-dimensional ultrasound current source density imaging of a dipole field

Four-dimensional ultrasound current source density imaging of a dipole field

Experimental setup for developing acousto-electric interaction imaging

Application of acoustic-electric interaction for neuro-muscular activity mapping: A review

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