193 results about "Acoustic radiation force" patented technology

Energy is transferred (336) to cause a mechanical property of biological tissue to change, as in ablation. An effect of the transferring is examined in more than one spatial dimension to, for example, make an ablation halting decision for a treatment region, i.e., line (312) or layer (314), or for a location (316) within the region. Halting decisions can be based on lesion-central and/or lesion-peripheral longitudinal displacement of treated tissue evaluated in real time against a characteristic curve. Steering in the azimuthal and/or elevation direction is afforded by, for example, linear, or 2D, multi-channel ultrasound arrays for therapy and imaging. Protocols includable are region-wide scanning (SI 010) and location-by-location completion for both (HIFU) therapy and tracking (acoustic-radiation-forced-based) displacement of treated tissue. Fine, location- to-location monitoring can be used for relatively inhomogeneous tissue; whereas, quicker, sparser and more generalized monitoring (1 100, 1200) can be employed for relatively homogeneous tissue.

Methods for determining the shear modulus of a tissue of an individual are disclosed. In one embodiment, an acoustic pulse is transmitted and a reference echo signal is received. A first push pulse is transmitted at a second location of the individual. A second push pulse is transmitted at a third location of the individual. A series of tracking pulses are transmitted at the first location and a tracking echo signal is received from each tracking pulse. The effect of the first and second push pulses on the tissue is determined through analysis of the tracking echo signals. The shear modulus of the tissue is calculated based on the effect of the push pulses on the tissue. A system for imaging a region of tissue is presented.

Devices for separating materials from a host fluid are disclosed. The devices include a flow chamber, an ultrasonic transducer, and a reflector. The ultrasonic transducer and reflector create an angled acoustic standing wave oriented at an angle relative to the direction of mean flow through the flow chamber. The angled acoustic standing wave results in an acoustic radiation force having an axial force component that deflects the materials, so that the materials and the host fluid can thus be separated. The angled acoustic standing wave can be oriented at an angle of about 20° to about 70° relative to the direction of mean flow through the flow chamber to deflect, collect, differentiate, or fractionate the materials from the fluid flowing through the device at flow rates of about 400 mL/min up to about 700 mL/min.

The invention discloses ultrasonic imaging method and device. The method comprises the following steps of: firstly carrying out coded modulation on a pulse generating an acoustic radiation force, and exciting a probe to emit an ultrasonic wave to generate a multi-frequency acoustic radiation force to generate tissue vibration; then adopting the coded modulation different from an exciting pulse for the pulse detecting the tissue vibration, ensuring the good correlation between two code words, and eliminating the interference caused by an exciting pulse echo generating the acoustic radiation force for a detection echo by utilizing a CDMA (Code Division Multiple Access) technology similar to communication, thereby improving the signal-to-noise ratio and increasing the energy of the acoustic radiation force by more fully utilizing the pulse width and the frequency band width resources of a system.

A method for determining a shear modulus of an elastic material with a known density value is provided. In this method, a spatially modulated acoustic radiation force is used to initially generate a disturbance of known spatial frequency or wavelength. The propagation of this initial displacement as a shear wave is measured using ultrasound tracking methods. A temporal frequency is determined based on the shear wave. The shear modulus of the elastic material at the point of excitation may be calculated using the values of the spatial wavelength, material density, and temporal frequency.

The present invention provides a method making stratified paper by redistributing the pulp suspension inside the headbox nozzle using acoustic radiation waves. Acoustic radiation forces fractionate fibers based on fiber radius. The acoustic radiation waves separate the fibers by pushing the coarse and longer fibers to the inner area while fines and smaller fibers remain in the outer area. This has a similar effect of multi-layer stratification headbox, and provides paper with a smoother surface.

The invention provides a tissue viscoelasticity measuring method based on shear wave amplitude and phase detection. An acoustic radiation force excitation probe and an ultrasonic echo detection probe are used for detection at the same time, the acoustic radiation force excitation probe generates push wave beams, tissue generates shear waves at certain frequency, the ultrasonic echo detection probe generates detection wave beams to detect amplitude attenuation and phase change of the shear waves on a propagation path, the elasticity modulus and viscosity coefficient of the tissue are estimated through an amplitude attenuation coefficient and a speed detection value, in other words, the elasticity modulus and viscosity coefficient of the tissue can be quantitatively detected at the same time, precise and rich mechanical parameter information is provided for diagnosis of multiple diseases, the clinical application range of ultrasonic elastography can be widened, and the level of ultrasonic elastography can be improved. The method can carry out detection through the shear waves at one frequency, the system complexity and design cost are reduced, detection efficiency is improved, phase detection noise caused by high-frequency shear waves is avoided, and the accuracy of mechanical tissue parameter detection is improved.

The invention discloses an acoustic surface wave based microfluidic plasma separating chip and method. The chip comprises a piezoelectric substrate, a set of interdigital transducer arranged on the piezoelectric substrate and a flow microchannel system which is arranged on the piezoelectric substrate in a bonding manner, located on one side of the interdigital transducer and has a necking structure. According to the chip, by use of width change of a microchannel, blood cells gradually shift to one side of a runner under the action of an acoustic radiation force, thus realizing the separation of plasma and blood cells. The chip takes such good advantages of the acoustic surface wave based microfluidic particle separation technology as high energy density and easy integration and manufacturing; in addition, only one set of interdigital transducer is arranged on the piezoelectric substrate and the distribution of an acoustic surface standing wave field is defined by a special geometrical shape of the PDMS flow microchannel; therefore, the defect that the existing acoustic surface wave based microfluidic particle separation technology requires two sets of interdigital transducer at the same time is overcome, the size of the separation chip is reduced further, and the requirement on alignment precision of the interdigital transducer and the microchannel system is reduced greatly.

The invention discloses a method for intravascular ultrasound multi-slice shear wave elastography. The method comprises the following steps of recording an original ultrasound echo signal of a tissue to be detected; enabling an interventional ultrasound array probe to generate acoustic radiation force by virtue of a short-pulse signal controlled by a computer; emitting ultrasonic pulse beams for many times to accept and detect a propagation process of shear waves generated by the acoustic radiation force; analyzing the propagation speed of the shear waves in the tissue to be detected to obtain a wave speed distribution image of the shear waves in the tissue; performing wave speed mapping on the shear waves at each position in the tissue to be detected to obtain a quantitative elastic image of the intravascular tissue. The method has the advantages of real time performance, quantification, high speed, high resolution and the like; a multi-array element intravascular transducer array is used for performing vascular wall tissue elastic information quantitative analysis to excite and track the shear waves; the further popularization and application of intravascular elastography are favorably promoted, and the early diagnosis capability of people in cardiovascular diseases is enhanced.

An apparatus and method for down hole gas separation from the multiphase fluid flowing in a wellbore or a pipe, for determining the quantities of the individual components of the liquid and the flow rate of the liquid, and for remixing the component parts of the fluid after which the gas volume may be measured, without affecting the flow stream, are described. Acoustic radiation force is employed to separate gas from the liquid, thereby permitting measurements to be separately made for these two components; the liquid (oil/water) composition is determined from ultrasonic resonances; and the gas volume is determined from capacitance measurements. Since the fluid flows around and through the component parts of the apparatus, there is little pressure difference, and no protection is required from high pressure differentials.

Disclosed is a system for controlling acoustic radiation from an aircraft. The system comprising a plurality of rotor systems (one or more) and a noise controller configured to regulate acoustic radiation from the plurality of rotor systems. The noise controller can be configured to regulate a commanded flight setting from the flight control system and to output a regulated flight setting to the plurality of rotor systems. Based on the regulated flight setting, the plurality of rotor systems are configured to generate, individually and in aggregate, acoustic radiation having a target acoustic behavior. The target acoustic behavior may be achieved using beamforming techniques to, for example, change the directionality of acoustic radiation from the plurality of rotor systems, or otherwise tune the acoustic radiation to reduce detectability and/or annoyance.

The invention discloses a system for controlling and selecting granules on basis of the structural sound field. The system comprises a sample table, an ultrasonic emitter and a manual structure. The sample table is used for storing to-be-selected granules, the ultrasonic emitter is used for emitting ultrasonic waves, and the manual structure is a circular structure and is used for modulating the sound field to generate stronger sound emissive power and to select the to-be-selected granules. The invention further discloses a method for controlling and selecting granules on basis of the structural sound field. The system comprises the sample table, the ultrasonic emitter and the manual structure, the ultrasonic emitter is used for emitting ultrasonic waves, the manual structure is a circular structure and is used for selecting the to-be-selected granules, a plurality of granules can be placed on the sample table, the manual structure can be used for modulating the sound field to generate stronger sound emissive power and can capture specific granules on the lower surface of the manual structure, so that the granules can be rapidly and massively selected and efficiency is improved.

In a method and an apparatus for magnetic resonance guided high intensity focused ultrasound (HIFU), precise localization of the focal point of the HIFU is determined by imaging an examination subject in parallel with GRE sequences that respectively include a positive monopolar gradient pulse and a negative monopolar gradient pulse, that respectively encode the acoustic radiation force (ARF)-induced phase shift that is induced by the simultaneous activation of HIFU during the sequences. A GRE phase image is reconstructed from each acquisition sequence, and a difference image is formed between the two GRE phase images, from which the HIFU focal point is determined. An average image is formed of the two GRE phase images from which PRFS temperature map is determined simultaneously to ARFI map. The use of parallel imaging and the use of partial Fourier reconstruction for reconstructing the GRE phase images allows the data to be acquired sufficiently rapidly so as to minimize the adverse effect of tissue heating that occurs with conventional longer-duration, and repetitious, techniques.

The invention provides for medical instrument (200, 400) comprising a magnetic resonance imaging system (202) and a high intensity focused ultrasound system (222). A processor (246) controls the medical instrument. Instructions cause the processor to control (100) the magnetic resonance imaging system to acquire the magnetic resonance data using a pulse sequence (254). The pulse sequence comprises an acoustic radiation force imaging pulse sequence (500, 600). The acoustic radiation force imaging pulse sequence comprises an excitation pulse (512) and a multi-dimensional gradient pulse (514) applied during the radio frequency excitation pulse for selectively exciting a region of interest (239) encompassing a target zone and at least a portion of the beam axis. The instructions cause the processor to control (102) the high intensity focused ultrasound system to sonicate the target zone during the acoustic radiation force imaging pulse sequence and reconstruct (104) a radiation force image (258) using the magnetic resonance data.

This invention relates to diagnostic and screening medical ultrasound in general and to ultrasound-stimulated detection and location, Image-based Dynamic Ultrasound Spectrography, Acoustic Radiation Force Imaging, and similar modalities in particular. In this invention, an ultrasound signal is emitted into tissue and the resulting radiation force induces localized lower frequency oscillations, which are then received by various acoustic sensors and analyzed to determine certain features or characteristics of the interrogated region. The sensors can be arranged in the form of a ring, in any random arrangements, or positioned in specifically chosen locations. An ultrasonic imaging and excitation transducer generates certain stimulating signals which are received by the breast tissues and which, if they contact a microcalcification, other target, or any region with sharply different mechanical and visco-elastic properties, will result in reflected, demodulated, or re-radiated signals. These signals will propagate away from the targets and detected by the various receiving sensors.

A medical ultrasound device is disclosed. The device comprises an elongated body having a proximal end and a distal end region (1). One or more ultrasound transducers (4) for generating acoustic radiation are positioned in the distal end region, inside the elongated body. A transmission element (5) which is substantially transparent to acoustic radiation is positioned in the radiation path of the acoustic radiation, and a controller unit is operatively connected to the ultrasound transducer. The transmission element and the one or more ultrasound transducers are mounted so that an acoustic path length (8) between the transmission element (5) and the ultrasound transducer (4) varies with contact force (10) imposed to the distal end region. The controller unit detects the acoustic path length between the ultrasound transducer and the transmission element and determines the contact force from the detected acoustic path length. In an embodiment, the medical device is an ultrasound RF ablation catheter.

The invention provides a piezoelectric underwater sound transducer acoustic radiation mode measurement method and system based on combination near-field acoustical holography. In the method, the combination near-field acoustical holography is utilized to reestablish sound field, sound pressure and radiation surface vibration velocity; on the basis of an acoustic radiation operator matrix obtained based on measurement data and with the sound field radiation theory being combined, the acoustic radiation power of a piezoelectric underwater sound transducer is expressed to be a positive definite quadric form; and positive definite and conjugate performance of the matrix are utilized to obtained an acoustic radiation mode of the structure. The system comprises a glass water tank, an industrial control computer with PXI bus, a transducer excitation module based on the PXI bus, a sound pressure and vibration velocity acquisition module and a three-dimensional motion platform. The method and system in the invention break the limitation that acoustic radiation mode in the current complex underwater structure can only be solved numerically, provide a new idea for research on the piezoelectric underwater sound transducer, and also provide basis for structure optimization of the piezoelectric underwater sound transducer.

An ultrasonometer for bone assessment in infants includes a focusing acoustic wave transducer, an acoustic wave detector, and an elongated chamber filled with an acoustically-coupling fluid. The chamber is equipped with an acoustically-transparent flexible membrane facing the extremity of the infant. Supporting means such as a gliding rod is adapted to retain at least one of the transducer or the detector inside the chamber facing the subject. Supporting means is further adapted to move the transducer or detector along the chamber to perform the bone scanning without repositioning of the probe. A focused ultrasound transducer is adapted to remotely generate an acoustic wave in the bone by acoustic radiation force.

The invention provides an ultrasonic shearing wave elastic imaging method based on dynamic aperture control. Array elements of which the number corresponds to different focus depths are started, the aperture is set up, grating lobe phenomena and false displacement in a displacement field can be effectively eliminated, an obtained mass point displacement-time curve relatively well meets the rule that a single point triggered shearing wave is attenuated along with time, and the shearing wave transmission speed measurement accuracy can be improved. By using the ultrasonic shearing wave elastic imaging method, the technical problems that in the prior art in shallow focus depth, because of the influence of acoustic radiation force grating lobe, a mark point displacement-time curve is deformed and the shearing wave transmission speed measurement accuracy is degraded can be solved.