Abstract: A medical imaging assembly includes an elongated catheter having a connector at the proximal end; an array of transducers on the distal end of the catheter; conductors electrically coupled to the array of transducers and in electrical communication with the connector of the catheter; and a control unit coupleable to the catheter to send and receive electrical signals between the control unit and the array of transducers through the connector of the catheter. The control unit has a processor to execute instructions including 1) selecting a first subset of M transmitting transducers and a second subset of N receiving transducers from the array of transducers, where N>M; and 2) for each of at least N transmit/receive cycles, a) directing the first subset of M transmitting transducers to transmit an acoustic signal; and b) directing the second subset of N receiving transducers to receive corresponding echo signals.

Abstract: A method for generating an ultrasound image includes receiving an image frame comprising consecutive ultrasound scan lines obtained using a rotating ultrasound imaging arrangement and determining at least a first cross-correlation value and a second cross-correlation value for each of a plurality of the scan lines. For each individual scan line of the plurality of scan lines, the first cross-correlation value comprises a cross-correlation coefficient between a first subframe comprising a plurality of consecutive scan lines including the individual scan line and a second subframe comprising a plurality of scan lines shifted from the first subframe by a first integer value. The second correlation value comprising a cross-correlation coefficient between the first subframe and a third subframe comprising a plurality scan lines shifted from the first subframe by a second integer value that is different from the first integer value.

Abstract: A method for real-time displaying of cross-sectional images during an intravascular ultrasound (IVUS) imaging procedure includes, during an intravascular ultrasound imaging procedure, receiving electrical signals from at least one transducer in a catheter as the at least one transducer rotates and moves longitudinally along a lumen of a patient blood vessel; during the intravascular ultrasound imaging procedure, processing the received electrical signals to form a series of cross-sectional images that are longitudinally-offset from one another along a length of the lumen; during the intravascular ultrasound imaging procedure, concurrently displaying i) a most recent image and ii) a previous image that is either a) selected by the operator or b) automatically selected as having a maximum or minimum of a selected image characteristic; and, during the intravascular ultrasound imaging procedure, updating the display of the most recent image as a new image from the series of cross-sectional images is processed.

Abstract: A method for generating an ultrasound image includes receiving an image frame having consecutive ultrasound scan lines obtained using a rotating ultrasound imaging arrangement and determining first and second cross-correlation values for a plurality of the scan lines. For each individual scan line, the first cross-correlation value includes a cross-correlation coefficient between a first subframe of consecutive scan lines including the individual scan line and a second subframe of scan lines shifted from the first subframe by a first integer value. The second correlation value includes a cross-correlation coefficient between the first subframe and a third subframe of scan lines shifted from the first subframe by a second integer value. The method further includes evaluating, individually for multiple scan lines, whether that scan line exhibits non-uniform rotation distortion using at least one of the first and second cross-correlation values. A correction for non-uniform rotation distortion is applied.

Abstract: A method for processing a sequence of ultrasound frames for display includes receiving a sequence of intravascular ultrasound (IVUS) frames of a vessel having a lumen, the sequence including a first frame and a second frame; determining one or more texture features for each of one or more regions of the first frame; determining at least one flow feature for each of the one or more regions by comparing the first and second frames; deriving a lumen border for the first frame using the one or more texture features and the at least one flow feature to characterize the one or more regions as within or outside of the lumen of the vessel; and displaying an ultrasound image of the first frame with the lumen border.

Abstract: A medical imaging assembly includes an elongated catheter having a connector at the proximal end; an array of transducers on the distal end of the catheter; conductors electrically coupled to the array of transducers and in electrical communication with the connector of the catheter; and a control unit coupleable to the catheter to send and receive electrical signals between the control unit and the array of transducers through the connector of the catheter. The control unit has a processor to execute instructions including 1) selecting a first subset of M transmitting transducers and a second subset of N receiving transducers from the array of transducers, where N>M; and 2) for each of at least N transmit/receive cycles, a) directing the first subset of M transmitting transducers to transmit an acoustic signal; and b) directing the second subset of N receiving transducers to receive corresponding echo signals.

Abstract: A method for generating a composite image using an intravascular imaging device includes receiving reflected echo signals from at least one transducer along a first of a plurality of radial scan lines. The received echo signals are passed through a plurality of signal processing channels to form a plurality of filtered signals. The filtered signals include a high-resolution tissue structure signal and at least one first pre-blood-flow-mask signal. High-resolution tissue structure signals are processed to form a high-resolution tissue structural image. First pre-blood-flow-mask signals are cross-correlated with second pre-blood-flow-mask signals from an adjacent radial scan line to form blood-flow-mask signals. Blood-flow-mask signals are processed to form a blood-flow mask.

Abstract: A method for generating a composite image using an intravascular imaging device includes receiving reflected echo signals from at least one transducer along a first of a plurality of radial scan lines. The received echo signals are passed through a plurality of signal processing channels to form a plurality of filtered signals. The filtered signals include a high-resolution tissue structure signal and at least one first pre-blood-flow-mask signal. High-resolution tissue structure signals are processed to form a high-resolution tissue structural image. First pre-blood-flow-mask signals are cross-correlated with second pre-blood-flow-mask signals from an adjacent radial scan line to form blood-flow-mask signals. Blood-flow-mask signals are processed to form a blood-flow mask.

Abstract: A method for generating a composite image using an intravascular imaging device includes receiving reflected echo signals from at least one transducer along a first of a plurality of radial scan lines. The received echo signals are passed through a plurality of signal processing channels to form a plurality of filtered signals. The filtered signals include a high-resolution tissue structure signal and at least one first pre-blood-flow-mask signal. High-resolution tissue structure signals are processed to form a high-resolution tissue structural image. First pre-blood-flow-mask signals are cross-correlated with second pre-blood-flow-mask signals from an adjacent radial scan line to form blood-flow-mask signals. Blood-flow-mask signals are processed to form a blood-flow mask.

Abstract: A method for generating an ultrasound image includes receiving an image frame having consecutive ultrasound scan lines obtained using a rotating ultrasound imaging arrangement and determining first and second cross-correlation values for a plurality of the scan lines. For each individual scan line, the first cross-correlation value includes a cross-correlation coefficient between a first subframe of consecutive scan lines including the individual scan line and a second subframe of scan lines shifted from the first subframe by a first integer value. The second correlation value includes a cross-correlation coefficient between the first subframe and a third subframe of scan lines shifted from the first subframe by a second integer value. The method further includes evaluating, individually for multiple scan lines, whether that scan line exhibits non-uniform rotation distortion using at least one of the first and second cross-correlation values. A correction for non-uniform rotation distortion is applied.

Abstract: Contrast agent destruction transmissions have reduced biological effect in medical diagnostic ultrasound. Ramping-up amplitude and/or ramping-down frequency reduce biological effect. The amplitude ramps up linearly or non-linearly. The change in amplitude or frequency occurs over a single waveform or over a sequence of separate transmissions. An envelope of the single waveform or the sequence of separate transmissions has a non-uniform, asymmetrical, symmetrical, rectangular or other shape. For example, the frequency ramp-down is provided with a non-Gaussian envelope. The amplitude ramp-up or frequency ramp-down is a progressively increasing destructive characteristic or ability, destroying contrast agent at different regions relative to focal regions with a minimum of acoustic energy.

Abstract: Methods and systems for varying a pattern as a function of steering angle for medical imaging with a multidimensional array are provided. Transmit waveform, delay, phase or apodization patterns in addition to delays, phases or apodization for focusing are used with a multidimensional array. By applying a periodic variation perpendicular to the steering direction, the effects of grating lobes due to the variation may be reduced. Along the steering direction, additional offsets are not provided, but may be provided. This different or non-existent offsets provide less grating lobe clutter. The transmit aperture is adjusted to be parallel to a direction of steering of non-normal transmit scan line or scan lines. The variation pattern is selected to result in enhancement or isolation of one or more frequency bands from one or more other frequency bands, such as isolation of second harmonic information from fundamental transmit frequency information.

Abstract: Multiple receive beams are formed for each transmission for rapid acquisition. The receive aperture is shifted as a function of the position of each receive beam. Multiple receive beams with differently positioned apertures are formed in response to a single transmit beam. Alternatively or additionally, the apodization varies as a function of the position of the receive beam relative to the transmit beam. Multiple receive beams with different apodization profiles are formed in response to a single transmission. The apodization and/or aperture variations in different receive beams may reduce geometric distortion and/or clutter levels for receiving multiple beams in response to a single transmission.

Abstract: Control of the sonothrombolysis treatment is automated based on feedback from ultrasound. The region to be treated may be tracked to provide ongoing treatment at the desired location. The treatment may be triggered based on detection of sufficient perfusion. The number or intensity of destructive ultrasound pulses may adapt to the number of remaining contrast agents. The treatment may be ceased or modified based on the efficacy.

Abstract: The therapeutic ultrasound waveform is used as a source of stress or ARFI pushing pulse. When the therapeutic ultrasound waveform ceases, diagnostic ultrasound is used to measure the strain, such as measuring tissue displacement. The displacement over time after release of the stress indicates tissue characteristics. The tissue characteristics may be monitored to determine when sufficient therapeutic results are obtained.

Abstract: Contrast agents may more effectively clear a clot if they are as close to the clot as possible. Radiation force may effectively push and/or pull the contrast agents next to the clot and away from the middle of any flow channels. By transmitting driving acoustic energy, the contrast agents may be positioned for treatment that is more effective by destruction.

Abstract: Destructive or therapy events are indicated in medical ultrasound imaging. Audible, visual, vibratory or other feedback is provided to the user. The feedback indicates the use of the destructive or therapy events. A characteristic of the indicator may provide further information, such as the power level or other operating condition.

Abstract: Transducer with different array configurations and methods of using the transducers are provided. An electrode layer on one side of a transducer device defines a one-dimensional array of elements. An electrode layer on an opposite side of the transducer device defines a multi-dimensional array. For example, one transducer device may be used for both two-dimensional imaging and three-dimensional imaging in response to the one-dimensional array and multi-dimensional array electrode configurations. Real time three-dimensional imaging and two-dimensional imaging may be provided with a single transducer. As another example, elements defined by one electrode configuration have a different surface area than elements defined by another electrode configuration. The different configurations on opposite sides of the transducer devices may be a same type (e.g. both one-dimensional arrays) or different types.

Abstract: An image formed from compounded frames of ultrasound data acquired with different steering angles is displayed. Each component frame is associated with a scan of the entire displayed region. A majority of scan lines for each component frame are pointed in one direction or the same relative direction, and a minority of the scan lines are steered at different angles within each component frame to scan the rest of the display region, but with a different steering angle for the majority of scan lines of each of the component frames. As a result, the benefits of spatial compounding component frames associated with different steering angles are provided without having to apply filtering to reduce line artifacts.

Abstract: An image formed from compounded frames of ultrasound data acquired with different steering angles is displayed. Each component frame is associated with a scan of the entire displayed region. A majority of scan lines for each component frame are pointed in one direction or the same relative direction, and a minority of the scan lines are steered at different angles within each component frame to scan the rest of the display region, but with a different steering angle for the majority of scan lines of each of the component frames. As a result, the benefits of spatial compounding component frames associated with different steering angles are provided without having to apply filtering to reduce line artifacts.