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Ultrasound Current Source Density Im...

Li, Qian.

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Ultrasound Current Source Density Imaging in live rabbit hearts using clinical intracardiac catheter.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Ultrasound Current Source Density Imaging in live rabbit hearts using clinical intracardiac catheter./
Author:	Li, Qian.
Description:	135 p.
Notes:	Source: Dissertation Abstracts International, Volume: 76-10(E), Section: B.
Contained By:	Dissertation Abstracts International76-10B(E).
Subject:	Biomedical engineering. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3704868
ISBN:	9781321774863

Ultrasound Current Source Density Imaging in live rabbit hearts using clinical intracardiac catheter.
Li, Qian.

Ultrasound Current Source Density Imaging in live rabbit hearts using clinical intracardiac catheter. - 135 p.

Source: Dissertation Abstracts International, Volume: 76-10(E), Section: B.

Thesis (Ph.D.)--The University of Arizona, 2015.

Ultrasound Current Source Density Imaging (UCSDI) is a noninvasive modality for mapping electrical activities in the body (brain and heart) in 4-dimensions (space + time). Conventional cardiac mapping technologies for guiding the radiofrequency ablation procedure for treatment of cardiac arrhythmias have certain limitations. UCSDI can potentially overcome these limitations and enhance the electrophysiology mapping of the heart.

ISBN: 9781321774863Subjects--Topical Terms:

535387
Biomedical engineering.

Ultrasound Current Source Density Imaging in live rabbit hearts using clinical intracardiac catheter.
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020 $a 9781321774863
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100 1 $a Li, Qian. $3 1263199
245 1 0 $a Ultrasound Current Source Density Imaging in live rabbit hearts using clinical intracardiac catheter.
300 $a 135 p.
500 $a Source: Dissertation Abstracts International, Volume: 76-10(E), Section: B.
500 $a Adviser: Russell S. Witte.
502 $a Thesis (Ph.D.)--The University of Arizona, 2015.
520 $a Ultrasound Current Source Density Imaging (UCSDI) is a noninvasive modality for mapping electrical activities in the body (brain and heart) in 4-dimensions (space + time). Conventional cardiac mapping technologies for guiding the radiofrequency ablation procedure for treatment of cardiac arrhythmias have certain limitations. UCSDI can potentially overcome these limitations and enhance the electrophysiology mapping of the heart.
520 $a UCSDI exploits the acoustoelectric (AE) effect, an interaction between ultrasound pressure and electrical resistivity. When an ultrasound beam intersects a current path in a material, the local resistivity of the material is modulated by the ultrasonic pressure, and a change in voltage signal can be detected based on Ohm's Law. The degree of modulation is determined by the AE interaction constant K. K is a fundamental property of any type of material, and directly affects the amplitude of the AE signal detected in UCSDI.
520 $a UCSDI requires detecting a small AE signal associated with electrocardiogram. So sensitivity becomes a major challenge for transferring UCSDI to the clinic. This dissertation will determine the limits of sensitivity and resolution for UCSDI, balancing the tradeoff between them by finding the optimal parameters for electrical cardiac mapping, and finally test the optimized system in a realistic setting.
520 $a This work begins by describing a technique for measuring K, the AE interaction constant, in ionic solution and biological tissue, and reporting the value of K in excised rabbit cardiac tissue for the first time. K was found to be strongly dependent on concentration for the divalent salt CuSO4, but not for the monovalent salt NaCl, consistent with their different chemical properties. In the rabbit heart tissue, K was determined to be 0.041 +/- 0.012 %/MPa, similar to the measurement of K in physiologic saline: 0.034 +/- 0.003 %/MPa.
520 $a Next, this dissertation investigates the sensitivity limit of UCSDI by quantifying the relation between the recording electrode distance and the measured AE signal amplitude in gel phantoms and excised porcine heart tissue using a clinical intracardiac catheter. Sensitivity of UCSDI with catheter was 4.7 microV/mA (R2 = 0.999) in cylindrical gel (0.9% NaCl), and 3.2 microV/mA (R2 = 0.92) in porcine heart tissue. The AE signal was detectable more than 25 mm away from the source in cylindrical gel (0.9% NaCl). Effect of transducer properties on UCSDI sensitivity is also investigated using simulation. The optimal ultrasound transducer parameters chosen for cardiac imaging are center frequency = 0.5 MHz and f/number = 1.4.
520 $a Last but not least, this dissertation shows the result of implementing the optimized ultrasound parameters in live rabbit heart preparation, the comparison of different recording electrode configuration and multichannel UCSDI recording and reconstruction. The AE signal detected using the 0.5 MHz transducer was much stronger (2.99 microV/MPa) than the 1.0 MHz transducer (0.42 microV/MPa). The clinical lasso catheter placed on the epicardium exhibited excellent sensitivity without being too invasive. 3-dimensional cardiac activation maps of the live rabbit heart using only one pair of recording electrodes were also demonstrated for the first time. Cardiac conduction velocity for atrial (1.31 m/s) and apical (0.67 m/s) pacing were calculated based on the activation maps.
520 $a The future outlook of this dissertation includes integrating UCSDI with 2-dimensional ultrasound transducer array for fast imaging, and developing a multi-modality catheter with 4-dimensional UCSDI, multi-electrode recording and echocardiography capacity.
590 $a School code: 0009.
650 4 $a Biomedical engineering. $3 535387
650 4 $a Optics. $3 517925
690 $a 0541
690 $a 0752
710 2 $a The University of Arizona. $b Optical Sciences. $3 1019548
773 0 $t Dissertation Abstracts International $g 76-10B(E).
790 $a 0009
791 $a Ph.D.
792 $a 2015
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3704868