Abstract: A medical instrument system includes an elongate instrument body defining a longitudinal axis and capable of being twisted about its longitudinal axis and an optical fiber sensor coupled to the instrument body. A detector is operatively coupled to the optical fiber sensor and configured to detect respective light signals transmitted on the optical fiber sensor. A controller is operatively coupled to the detector and configured to determine a twist of a portion of the instrument body about its longitudinal axis based on an analysis of detected light signals.

Abstract: A method and system for maintaining calibration of a distributed localization system are presented. After a baseline calibration of sensors distributed on a working instrument and reference instrument, if movement of the reference instrument is detected, shape sensing data from a Bragg shape sensing fiber also coupled to the reference instrument may be utilized to recalibrate the localization system. The reference instrument preferably is located intraoperatively in a relatively constrained anatomical environment, such as in the coronary sinus of the heart, to prevent significant movement.

Abstract: Robotic medical instrument systems and associated methods utilizing an optical fiber sensors such as Bragg sensor optical fibers. In one configuration, an optical fiber is coupled to an elongate instrument body and includes a fiber core having one or more Bragg gratings. A controller is configured to initiate various actions in response thereto. For example, a controller may generate and display a graphical representation of the instrument body and depict one or more position and/or orientation variables thereof, or adjust motors of an instrument driver to reposition the catheter or another instrument. Optical fibers having Bragg gratings may also be utilized with other system components including a plurality of working instruments that are positioned within a sheath lumen, an instrument driver, localization sensors, and/or an image capture device, and may also be coupled to a patient's body or associated structure that stabilizes the body.

Abstract: A medical instrument system includes an elongate flexible instrument body with an optical fiber substantially encapsulated in a wall of the instrument body, the optical fiber including one or more fiber gratings. A detector is operatively coupled to the optical fiber and configured to detect respective light signals reflected by the one or more fiber gratings. A controller is operatively coupled to the detector, and configured to determine a twist of at least a portion of the instrument body based on detected reflected light signals. The instrument may be a guide catheter and may be robotically or manually controlled.

Abstract: Speckle is reduced by compounding. 1.25, 1.5, 1.75 and 2D arrays are used to obtain frames of data representing a same scan plane, but with different elevation spatial frequency content. The elevation aperture for one frame of data is different than an elevation aperture of another frame of data. The frames of data responsive to the different elevation apertures are compounded, reducing speckle.

Abstract: Speckle is reduced by compounding. 1.25, 1.5, 1.75 and 2D arrays are used to obtain frames of data representing a same scan plane, but with different elevation spatial frequency content. The elevation aperture for one frame of data is different than an elevation aperture of another frame of data. The frames of data responsive to the different elevation apertures are compounded, reducing speckle.

Abstract: A method and system for obtaining ultrasound data is provided. Different aperture techniques are used for transmit than on receive. The various techniques include synthetic aperture, shorting elements, skipping elements, sliding apertures and combinations thereof. The techniques used may also vary as a function of the depth of field.

Abstract: A medical diagnostic ultrasonic imaging method and system subdivide the transmit aperture into two or more subapertures, each subaperture having at least four adjacent transducer elements. The subapertures are phased differently with respect to one another to selectively reduce either fundamental components or harmonic components of echoes from tissue. These techniques can be used to improve contrast agent harmonic imaging as well as tissue harmonic imaging, depending upon the phase shift selected.

Abstract: An improvement to the method for harmonic imaging including the steps of (a) transmitting ultrasonic energy at a fundamental frequency and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency is provided. The transmitting step includes the step of: applying the plurality of waveforms to a respective plurality of transducer elements, a first waveform of the plurality of waveforms characterized by a first value of a harmonic power ratio, waveforms transmitted from the transducer elements and corresponding to the plurality of waveforms summing as an acoustic waveform substantially at the point, the acoustic waveform characterized by a second value of the harmonic power ratio less than the first value. The imaging method can also include a step for subdividing the transmit aperture into two or more subapertures, each subaperture having at least four adjacent transducer elements.

Abstract: A method and system for obtaining ultrasound data is provided. Two or more transducer elements are shorted or connected to the same transmit or receive channel for a single transmit or receive event. The affect of any grating lobes generated from shorting the transducer elements are minimized by receiving acoustic energy and then obtaining ultrasound data at a harmonic of a fundamental transmit frequency. No contrast agent is added during imaging. A multiplexer with a limited number of switches is used to short pairs of transducer elements together. Alternatively, a multiplexer with a limited number of switches is used to transmit or receive from spaced apertures, such as by connecting a channel to every second transducer element.

Abstract: A medical diagnostic ultrasound imaging system and method modulate the image signal as a function of the ratio of the harmonic receive signal to the fundamental receive signal. Tissue harmonic backscatter differs substantially in spectral shape as compared to contrast agent backscatter, and this method allows improved discrimination between contrast agent and tissue backscatter.

Abstract: A method of imaging to aid tissue viability determinations is provided. Tissue motion is detected for at least region of tissue. Perfusion is estimated as a function of intensity data and time for the region of tissue. An image responsive to the detected tissue motion and the estimated perfusion is displayed. A combination of tissue motion imaging and perfusion estimation provides an assessment of tissue viability. If tissue exhibits perfusion and motion, then the tissue is likely normal. Any other perfusion and motion characteristic combination indicates abnormal tissue viability.

Abstract: An improvement to the method for harmonic imaging including the steps of (a) transmitting ultrasonic energy at a fundamental frequency and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency is provided. For the improvement, the transmitting step includes the step of transmitting a uni-polar waveform or a waveform characterized by an amplitude change rate of 8 or fewer times pre carrier cycle, said waveform comprising an envelope shape rising gradually to a respective maximum value and falling gradually from the respective maximum value.

Abstract: An ultrasound system and method are provided for improving resolution and operation. The system applies different imaging parameters within and outside a region of interest in an ultrasound image to improve spatial and/or temporal resolution inside a region of interest. The system also increases an apparent frame rate within a region of interest in an ultrasound-image frame by generating a motion-compensated interpolated image based on measured motion. The ultrasound imaging system also performs a method for automatically adjusting ultrasound imaging parameters in at least a portion of an ultrasound image in response to transducer or image motion to improve spatial or temporal resolution. With the measured motion, the system can also alter an operating mode of an ultrasound transducer array in response to an absence of transducer motion. Further, the system corrects distortion in an acquired ultrasound image caused by transducer or image motion.

Abstract: A method and apparatus for ultrasound imaging of Doppler energy-related parameters is described. An ultrasound imaging system includes a transducer for transmitting an ultrasound signal into a body and receiving a reflected ultrasound signal. The system determines the energy of the reflected signal from tissue within the body. Signal processing circuitry determines a Doppler intensity spectrum of the signal reflected from the tissue. The Doppler spectrum represents energy of the tissue-reflected signal as a function of Doppler frequency and time. Integration circuitry integrates the Doppler spectrum over Doppler frequency to determine the energy of the tissue-reflected signal as a function of time for display in strip mode. The system also determines an energy-velocity product.

Abstract: An improvement to the method for harmonic imaging including the steps of (a) transmitting ultrasonic energy at a fundamental frequency and (b) receiving reflected ultrasonic energy at a harmonic of the fundamental frequency is provided. The transmitting step includes the step of transmitting a waveform comprising at least a sequence of at least a first and second pulse characterized by first and second pulse durations, respectively, where the second pulse duration is different than the first duration. This arrangement can reduce harmonic energy in the waveform.