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Capacitive micromachined ultrasonic transducer (CMUT) arrays are conveniently integrated with frontend integrated circuits either monolithically or in a hybrid multichip form. This integration helps with reducing the number of active data processing channels for 2D arrays. This approach also preserves the signal integrity for arrays with small elements. Therefore CMUT arrays integrated with electronic...
Our Bioengineering Research Partnership grant, ldquoHigh Frequency Ultrasound Arrays for Cardiac Imagingrdquo, including the individuals cited at the end of this paper - Douglas N. Stephens (UC Davis), Matthew O'Donnell (UW Seattle), Kai Thomenius (GE Global Research), Aaron M. Dentinger (GE Global Research), Douglas Wildes (GE Global Research), Peter Chen (St. Jude Medical), K. Kirk Shung (University...
Low signal-to-noise ratio regions and large deformations in myocardial strain imaging cause peak hopping artifacts, especially near peak systole. To solve this problem, we propose a multi-resolution Viterbi search algorithm to maximally utilize tissue continuity and finite strain constraints to improve displacement estimation. Data from an isolated rabbit heart experiment were used to validate the...
We describe the first mapping of biological current in a live heart using ultrasound current source density imaging (UCSDI). Ablation procedures that treat severe heart arrhythmias require detailed maps of the cardiac activation wave. UCSDI can potentially improve on existing mapping procedures which are time-consuming and limited by its poor spatial resolution (5-10 mm). UCSDI is based on a pressure-induced...
Correlation-based speckle tracking methods are commonly used in elasticity imaging to estimate displacements. In the presence of local strain, a larger window size (in cross correlation calculation) results in larger displacement error. To reduce tracking error, we proposed using a short window followed by a correlation coefficient filter. Although simulation and experimental results demonstrated...
Ultrasound strain and strain rate imaging have been proposed to detect myocardial muscle viability and contractility change. However, it's not easy to control experimental parameters and acquire high SNR data during in-vivo animal experiments. To address this, we performed 2D cardiac elasticity imaging on a well-controlled isolated retroperfused rabbit heart paced through the apex. The excitation-contraction...
Neural contrast agents have a vast array of applications from molecular imaging to mapping membrane potential. We describe a hybrid neural recording system capable of ultrasonic, photoacoustic and optical imaging designed to develop and test the next-generation of neural contrast agents. Photoacoustic imaging (PA), in particular, provides optical contrast with good penetration and high spatial resolution,...
An optimized elastic modulus reconstruction procedure from ultrasound strain and pulse wave velocity (PWV) measurements was validated using a commercial ultrasound scanner. Longitudinal and transverse scans were performed on a vessel phantom connected to a pulsatile pump. Time delay between the ultrasound beams at each side of the transducer determines PWV and transverse elasticity imaging estimates...
The thermoelastic effect in a thin film is used to produce high-frequency, high-intensity ultrasound for applications in water and soft tissue. We have fabricated a structure that consists of 2D arrangements of gold nanoparticles, sandwiched between a transparent substrate and a 4.5 mum thick PDMS layer. The acoustic signal displays significant improvements compared to a bulk black PDMS film (the...
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