Successful ultrasound data collection strongly relies on the skills of the operator. Among different scans,
echocardiography is especially challenging as the heart is surrounded by ribs and lung tissue. Less experienced users
might acquire compromised images because of suboptimal hand-eye coordination and less awareness of artifacts.
Clearly, there is a need for a tool that can guide and train less experienced users to position the probe optimally. We
propose to help users with hand-eye coordination by displaying lines overlaid on B-mode images. The lines indicate the
edges of blockages (e.g., ribs) and are updated in real time according to movement of the probe relative to the blockages.
They provide information about how probe positioning can be improved. To distinguish between blockage and acoustic
window, we use coherence, an indicator of channel data similarity after applying focusing delays. Specialized
beamforming was developed to estimate coherence. Image processing is applied to coherence maps to detect unblocked
beams and the angle of the lines for display. We built a demonstrator based on a Philips iE33 scanner, from which
beamsummed RF data and video output are transferred to a workstation for processing. The detected lines are overlaid
on B-mode images and fed back to the scanner display to provide users real-time guidance. Using such information in
addition to B-mode images, users will be able to quickly find a suitable acoustic window for optimal image quality, and
improve their skill.
The ultrasonic vibration potential refers to the voltage generated when ultrasound traverses a colloidal or ionic
fluid. The theory of imaging based on the vibration potential is reviewed, and an expression given that can be
used to determine the signal from arbitrary objects. The experimental apparatus consists of a pair of parallel
plates connected to the irradiated body, a low noise preamplifier, a radio frequency lock-in amplifier, translation
stages for the ultrasonic transducer that generates the ultrasound, and a computer for data storage and image
formation. Experiments are reported where bursts of ultrasound are directed onto colloidal silica objects placed
within inert bodies.
The ultrasonic vibraton potential refers to the production of a voltage that varies in time when ultrasound passes through a colloidal or ionic solution. The vibration potential can be used as an imaging method for soft tissue by recording its phase, time of arrival, and magnitude relative to the launching of a burst of ultrasound. A theory of the effect can be found from Maxwell's equations. Experimental results demonstrating the imaging method are shown for bodies with simple geometries.
We show that the radiation pressure exerted by a beam of ultrasound can be used for contrast enhancement in high resolution x-ray imaging of tissue. Interfacial features of objects are highlighted as a result of both the displacement introduced by the ultrasound and the inherent sensitivity of x-ray phase contrast imaging to density variations. The potential of the method is demonstrated by imaging various tumor phantoms and tumors from mice. The directionality of the acoustic radiation force and its localization in space permits the imaging of ultrasound-selected tissue volumes. In a related effort we report progress on development of an imaging technique using and electrokinetic effect known as the ultrasonic vibration potential. The ultrasonic vibration potential refers to the voltage generated when ultrasound traverses a colloidal or ionic fluid. The theory of imaging based on the vibration potential is reviewed, and an expression given that describes the signal from an arbitrary object. The experimental apparatus consists of a pair of parallel plates connected to the irradiated body, a low noise preamplifier, a radio frequency lock-in amplifier, translation stages for the ultrasonic transducer that generates the ultrasound, and a computer for data storage and image formation. Experiments are reported where bursts of ultrasound are directed onto colloidal silica objects placed within inert bodies.
Recording of an ultrasonic vibration potential when a burst of ultrasound traverses a body containing a colloidal object can be used as the basis for an imaging method. The fundamentals of the theory of signal production and experimental demonstration of the imaging method are given. In a second imaging method, the use of ultrasound to modify x-ray phase contrast images where the ultrasound acts as a kind of "phase contrast" agent used to translate objects in space is demonstrated.
The ultrasonic vibration potential refers to the generation of a potential when ultrasound traverses a colloidal or ionic solution. The vibration potential can be used for imaging of tissue by sending a burst of ultrasound into a body and recording the vibration potential on the surface of the body with a pair of electrodes attached to a preamplifier and signal processing electronics. The theory of imaging in one-dimension is based on an integral of the ultrasound burst over the colloid distribution in space. A complete theory gives the current from the vibration potential as an integral of the product of the pressure with the component of the gradient of the colloid distribution in space in the direction of propagation of the ultrasound.