Properties of phantom tissuelike polymethylpentene in the frequency range 20-70 MHZ.

Quantitative ultrasound (QUS) has been used to characterize soft tissues at ordinary abdominal ultrasound frequencies (2 to 15 MHz) and is beginning application at high frequencies (20 to 70 MHz). For example, backscatter and attenuation coefficients can be estimated in vivo using a reference phantom. At high frequencies, it is crucial that reverberations do not compromise the measurements.

Nonlinear contrast imaging with an array-based micro-ultrasound system.

The main goal of this study was to determine the optimal strategy for a real-time nonlinear contrast mode for small-animal imaging at high frequencies, on a new array-based micro-ultrasound system. Previously reported contrast imaging at frequencies above 15 MHz has primarily relied on subtraction schemes involving B-mode image data. These approaches provide insufficient contrast to tissue ratios under many imaging conditions.

A new 15-50 MHz array-based micro-ultrasound scanner for preclinical imaging.

Most institutions now have a suite of imaging tools to follow mouse models of human disease. Micro-ultrasound is one of these tools and is second after whole-mouse fluorescence or bioluminescent imaging, in terms of installed systems. We report in this paper the first commercially available array transducer-based ultrasound imaging system that enables micro-ultrasound imaging at center frequencies between 15 and 50 MHz.

Performance and characterization of new micromachined high-frequency linear arrays.

A new approach for fabricating high frequency (> 20 MHz) linear array transducers, based on laser micromachining, has been developed. A 30 MHz, 64-element, 74-microm pitch, linear array design is presented. The performance of the device is demonstrated by comparing electrical and acoustic measurements with analytical, equivalent circuit, and finite-element analysis (FEA) simulations.

A new ultrasound instrument for in vivo microimaging of mice.

We report here on the design and evaluation of the first high-frequency ultrasound (US) imaging system specifically designed for microimaging of the mouse. High-frequency US or US biomicroscopy (UBM) has the advantage of low cost, rapid imaging speed, portability and high resolution. In combination with the ability to provide functional information on blood flow, UBM provides a powerful method for the investigation of development and disease models.

Development of methods to analyse transcranial Doppler ultrasound signals recorded in microgravity.

During space flights, several clinical syndromes may be the result of changes in cerebral circulation. The purpose of the paper is to describe the development and initial evaluation of a system for recording, processing and displaying transcranial Doppler ultrasound (TCD) waveforms from the middle cerebral artery (MCA) in microgravity. Volunteers were repeatedly subjected to 15-20 s intervals of microgravity ('near zero gravity') during flights on the KC-135 military aircraft.