Abstract:
L'invention propose un procédé de commande multi-impulsionnel de transducteurs cMUT en échographie à ultrasons en mode d'imagerie harmonique, et en particulier avec agents de contraste. Ce procédé comprend une émission d'une séquence de trois impulsions, dont les échos sont combinés pour constituer une image. Selon l'invention, ladite séquence de tensions comprend trois tensions de polarisation d'amplitudes différentes au sein de chaque séquence. Pour constituer une image par combinaison additive de trois valeurs mesurées pour lesdits trois échos, chaque valeur est multipliée par un coefficient déterminé en fonction de la valeur des tensions de polarisation. Cette combinaison annule ainsi la réflexion linéaire due aux transducteurs. Selon une particularité, les trois impulsions "combinées" ont des tensions différentes respectivement d'un facteur un, deux et trois. Dans des configurations en mode "pulse", où les transducteurs utilisés en réception sont tous commandés avec la même tension de polarisation, les échos reçus sont alors combinés selon : E1+E3-2*E2.
Abstract:
The invention relates to a method for measuring perfusion in an object using a contrast medium. According to said method, a defined number of scans is respectively produced of an object region during at least two reconcentration or depletion processes in different temporal process segments. The production of scans is completed before reaching a state of saturation or the complete destruction of the contrast medium at least during a reconcentration or depletion process, and a model of a reconcentration or depletion process is calculated on the basis of the series of sectional images produced in this way, reconcentration or depletion states being determined by means of mathematical approximation methods in time intervals during which no series of sectional images have been recorded. The invention also relates to a device for carrying out the method.
Abstract:
Provided herein are Pulse-Inversion (PI) sequences that provide for fundamental frequency suppression in nonlinear imaging applications. In an embodiment, a weighting scheme is applied to the received echo pulses resulting from transmit pulses of alternating polarity to reduce the effect of transducer motion. In an embodiment, a three-pulse weighting scheme is applied to a PI sequence. In other embodiments, different combinations of the three-pulse weighting scheme are applied to a PI sequence.
Abstract:
A method and device for imaging contrast agents which oscillate nonlinearly in a nondestructive mode at an MI in excess of 0.1 is described. Three transmit pulses are transmitted in each beam direction which are differently modulated. In an illustrated embodiment the transmit pulses are symmetrically differently phase modulated at 0°, 120° and 240°. The echoes received in response to each transmit pulse are stored and combined by a pulse inversion processor. Pulse inversion processing results in separation of the third harmonic to the relative exclusion of the first and second harmonic signal components. Third harmonic images of the contrast image are formed which exhibit a relatively low tissue background.
Abstract:
Provided herein are compositions comprising a microbubble contrast agent, wherein at least 20% by volume of the microbubbles in the contrast agent has a size of less than 1 micron, wherein the contrast agent produces non-linear scattering when contacted by ultrasound at a frequency above 20 MHz. Provided herein are compositions comprising a microbubble contrast agent, wherein at least 10% by volume of the microbubbles in the contrast agent has a size of less than 500 nanometers, wherein the contrast agent produces non-linear scattering when contacted by ultrasound at a frequency above 20 MHz. Provided herein are compositions comprising a microbubble contrast agent, wherein at least 5% by volume of the microbubbles in the contrast agent has a size of less than 200 nanometers, wherein the contrast agent produces non-linear scattering when contacted by ultrasound at a frequency above 20 MHz. The disclosed contrast agents can be targeted contrast agents. Further provided are methods of using the compositions disclosed herein. Specifically provided are methods for producing an ultrasound image comprising: administering contrast agent to a laboratory animal; generating ultrasound at a frequency of at least 20 MHz; transmitting ultrasound at a frequency of at least 20 MHz into the subject; receiving non-linear ultrasound from the contrast agent in the subject; processing the received ultrasound to provide an image.
Abstract:
An ultrasonic diagnostic imaging system and method are presented for producing spatially compounded images of harmonic contrast agents which are separated by the pulse inversion technique. Beams with different modulation characteristics are transmitted in different look directions. Aligned beams are combined by a nonlinear signal separator to separate harmonic contrast signal components by pulse inversion. The harmonic contrast signals from the different look directions are combined by a spatial compounding processor to produce a spatially compounded harmonic contrast image. In an illustrated embodiment the spatially compounded harmonic contrast image overlays a tissue image. Different modulation and beam steering techniques such as multiline acquisition are also disclosed for spatial compounding of contrast agent images.
Abstract:
The present invention is directed to a method for detecting an ultrasound contrast agent in a soft tissue and quantitating blood perfusion through regions of tissue by detecting the contrast agent in the tissue.