Abstract: A method and apparatus are provided for reducing distortion in a dynamically delayed digital sample stream of an imaging system. The method includes the steps of delta-sigma modulating an input analog signal of the imaging system at a frequency above the Nyquist frequency of the input analog signal to generate a digital sample stream and changing a length of the sample stream to delay a portion of the sample stream while maintaining synchronism between a delta-sigma modulator and a demodulator of the system.

Abstract: Apparatuses and methods for performing non-invasive vasectomies are provided. In a preferred embodiment, an apparatus according to the present invention comprises a main body defining a recess and an ultrasonic transducer disposed adjacent said recess and adapted to emit ultrasonic energy into said recess. A tissue clamp is removeably disposed in the recess and is adapted to receive parallel sections of a scrotum that include a portion of the vas deferens. The clamp is further adapted to position the vas deferens within an effective distance of the ultrasonic transducer. Also, the apparatus includes means for retaining the parallel sections and the vas deferens within the clamp during a procedure.

Abstract: A method and apparatus are provided for reducing distortion in a dynamically delayed digital sample stream of an imaging system. The method includes the steps of delta-sigma modulating an input analog signal of the imaging system at a frequency above the Nyquist frequency of the input analog signal to generate a digital sample stream and changing a length of the sample stream to delay a portion of the sample stream while maintaining synchronism between a delta-sigma modulator and a demodulator of the system.

Abstract: An ultrasound transducer array (408) includes at least one transducer element (412) having a first (604) and second (606) portions separated by an acoustical discontinuity (520). The first portion (604) has the desired length to form a half-wave k31 resonance, while the second portion (606) has a resonant length for an undesired very low frequency out-of-band k31 resonance. The thickness of the transducer element (412) is designed for k33 half-resonance. Given the design, the transducer element (412) can operate and provide for both forward-looking (514) and side looking (512) elevation apertures. A method is also disclosed for using the disclosed ultrasound transducer (412) in ultrasound imaging.

Abstract: A method and system to create and acoustically manipulate without destroying a microbubble which, in biological applications, can manipulate structures such as cells and subcellular structures at a nanoscopic scale.

Abstract: An acoustic monitoring method and system in laser-induced optical breakdown (LIOB) provides information which characterize material which is broken down, microbubbles in the material, and/or the microenvironment of the microbubbles. In one embodiment of the invention, femtosecond laser pulses are focused just inside the surface of a volume of aqueous solution which may include dendrimer nanocomposite (DNC) particles. A tightly focused, high frequency, single-element ultrasonic transducer is positioned such that its focus coincides axially and laterally with this laser focus. When optical breakdown occurs, a microbubble forms and a shock or pressure wave is emitted (i.e., acoustic emission). In addition to this acoustic signal, the microbubble may be actively probed with pulse-echo measurements from the same transducer. After the microbubble forms, received pulse-echo signals have an extra pulse, describing the microbubble location and providing a measure of axial microbubble size.

Abstract: Apparatuses and methods for performing non-invasive vasectomies are provided. In a preferred embodiment, an apparatus according to the present invention comprises a main body defining a recess and an ultrasonic transducer disposed adjacent said recess and adapted to emit ultrasonic energy into said recess. A tissue clamp is removeably disposed in the recess and is adapted to receive parallel sections of a scrotum that include a portion of the vas deferens. The clamp is further adapted to position the vas deferens within an effective distance of the ultrasonic transducer. Also, the apparatus includes means for retaining the parallel sections and the vas deferens within the clamp during a procedure.

Abstract: A medical ultrasonic imaging system uses an adaptive multi-dimensional back-end mapping stage to eliminate loss of information in the back-end, minimize any back-end quantization noise, reduce or eliminate electronic noise, and map the local average of soft tissue to a target display value throughout the image. The system uses spatial variance to identify regions of the image corresponding substantially to soft tissue and a noise frame acquired with the transmitters turned off to determine the mean system noise level. The system then uses the mean noise level and the identified regions of soft tissue to both locally and adaptively set various back-end mapping stages, including the gain and dynamic range.

Abstract: An ultrasound transducer array (408) includes at least one transducer element (412) having a first (604) and second (606) portions separated by an acoustical discontinuity (520). The first portion (604) has the desired length to form a half-wave k31 resonance, while the second portion (606) has a resonant length for an undesired very low frequency out-of-band k31 resonance. The thickness of the transducer element (412) is designed for k33 half-resonance. Given the design, the transducer element (412) can operate and provide for both forward-looking (514) and side looking (512) elevation apertures. A method is also disclosed for using the disclosed ultrasound transducer (412) in ultrasound imaging.

Abstract: An ultrasound transducer array (408) includes at least one transducer element (412) having a first (604) and second (606) portions separated by an acoustical discontinuity (520). The first portion (604) has the desired length to form a half-wave k31 resonance, while the second portion (606) has a resonant length for an undesired very low frequency out-of-band k31 resonance. The thickness of the transducer element (412) is designed for k33 half-resonance. Given the design, the transducer element (412) can operate and provide for both forward-looking (514) and side looking (512) elevation apertures. A method is also disclosed for using the disclosed ultrasound transducer (412) in ultrasound imaging.

Abstract: An ultrasound transducer array (408) includes at least one transducer element (412) having a first (604) and second (606) portions separated by an acoustical discontinuity (520). The first portion (604) has the desired length to form a half-wave k31 resonance, while the second portion (606) has a resonant length for an undesired very low frequency out-of-band k31 resonance. The thickness of the transducer element (412) is designed for k33 half-resonance. Given the design, the transducer element (412) can operate and provide for both forward-looking (514) and side looking (512) elevation apertures. A method is also disclosed for using the disclosed ultrasound transducer (412) in ultrasound imaging.

Abstract: A medical ultrasonic imaging system uses an adaptive multi-dimensional back-end mapping stage to eliminate loss of information in the back-end, minimize any back-end quantization noise, reduce or eliminate electronic noise, and map the local average of soft tissue to a target display value throughout the image. The system uses spatial variance to identify regions of the image corresponding substantially to soft tissue and a noise frame acquired with the transmitters turned off to determine the mean system noise level. The system then uses the mean noise level and the identified regions of soft tissue to both locally and adaptively set various back-end mapping stages, including the gain and dynamic range.

Abstract: An ultrasonic imaging system and method provide whitening using a two dimensional pre-detection filter followed by low pass filtering using a two dimensional post-detection filter to reduce speckle variance and enhance spatial resolution of the resulting image. The amplitude of the whitened signal can be adjusted as a function of variance or gradient of the ultrasonic receive signal to reduce undesired side lobes.

Abstract: A method and apparatus are provided for reducing distortion in a dynamically delayed digital sample stream of an imaging system. The method includes the steps of delta-sigma modulating an input analog signal of the imaging system at a frequency above the Nyquist frequency of the input analog signal to generate a digital sample stream and changing a length of the sample stream to delay a portion of the sample stream while maintaining synchronism between a delta-sigma modulator and a demodulator of the system.

Abstract: An ultrasonic imaging system and method provide whitening using a two dimensional pre-detection filter followed by low pass filtering using a two dimensional post-detection filter to reduce speckle variance and enhance spatial resolution of the resulting image.

Abstract: A method and apparatus are provided for reducing distortion in a dynamically delayed digital sample stream of an imaging system. The method includes the steps of delta-sigma modulating an input analog signal of the imaging system at a frequency above the Nyquist frequency of the input analog signal to generate a digital sample stream and changing a length of the sample stream to delay a portion of the sample stream while maintaining synchronism between a delta-sigma modulator and a demodulator of the system.

Abstract: A blood flow detection and imaging method and system is described for displaying images in accordance with signals transmitted from an intravascular ultrasound transducer probe. The image processor includes means for independently designating persistence factors for smoothing calculated speed and power of the dynamic portion of a field of view within a vasculature. Furthermore, the designation of a particular image point within a field of view as a dynamic image point (such as a blood flow region) as opposed to a static image point (such as a tissue region) is determined by averaging signal values for image points proximate to an image point of interest over both time and space.

Abstract: A method for measuring Doppler ultrasound information transmits a transmit beam having a frequency dependent focus in which low-frequency components of the transmit beam are focused at long ranges and progressively higher frequency components of the transmit beam are focused at progressively shorter ranges. Beamformed receive signals are generated in response to receive signals from the transducers, and these beamformed receive signals are applied to Doppler processors. The frequency dependent focus of the transmit beam provides a transmit beam that is more uniform in width and intensity, and the Doppler processors thereby provide an improved Doppler image signal.

Abstract: An opto-acoustic detector includes a fiber laser having a cavity which includes an optical fiber having an active medium portion doped with a gain material so that the detector may be used in high frequency, high density arrays. The cavity is bounded by a frequency selective reflector and a broadband or frequency selective reflector adapted to be acoustically coupled to a medium supporting ultrasound radiation (i.e. acoustic waves). In one embodiment, the frequency selective reflector is a diffraction grating placed external to the optical fiber. In another embodiment, the frequency selective reflector is a narrowband reflector placed directly in the optical fiber. An acoustic signal enhancing feature which increases sensitivity of the detector is provided by utilizing a reflective membrane having a thickness substantially less than the acoustic wavelength, .lambda., as the broadband optical reflector.

Abstract: A method and system are provided for 3-D acoustic microscopy using short pulse laser excitation. A 3-D acoustic microscope for use in such a system is also provided. In a first embodiment, wherein optical detection is utilized, a focused excitation beam is scanned by a first acoustooptic scanning device across an absorbing layer of an opto-acoustic transducer (if needed) coupled to an object under investigation to create spherical ultrasonic waves within the object which may be living tissue. The reflected spherical ultrasonic waves are detected through the use of an unfocused probe beam and an optical detector array or a focused probe beam and a single photodetector which receive the probe beam from a reflecting surface of the opto-acoustic transducer. A second acoustooptic scanning device scans the probe beam at a plurality of positions on the reflecting surface of the opto-acoustic transducer.