Abstract: The method of the invention controls an ultrasound system to identify a boundary between a tissue region and a blood-filled region that lies within an ROI. The method initially administers a contrast agent to the region of interest and then transmits first and second ultrasound beams at a different power levels into the ROI. Signal returns from the first and second beams are processed to derive first and second digital values, respectively. It has been determined that, under certain circumstances, a phase change of echo returns occurs at the boundary between tissue and blood-containing contrast agent. Detection of the phase change enables precise identification of the boundary, based upon the time segment in which the phase change is detected. Accordingly, time segment values of the first and second stored digital values are then phase-compared to enable determination of a boundary location between the tissue region and the blood-filled region by detection of the phase change.

Abstract: An ultrasonic imaging system having a real-time arbitrary mmode. A scan converter scan converts slices in real-time of a two-dimensional ultrasonic image which form an arbitrary user-defined curve within the two-dimensional ultrasonic image. The scan converted slices are used to display the curve as a time versus depth mmode image.

Abstract: An ultrasonic imaging system having a real-time arbitrary mmode. A scan converter scan converts slices in real-time of a two-dimensional ultrasonic image which form an arbitrary user-defined curve within the two-dimensional ultrasonic image. The scan converted slices are used to display the curve as a time versus depth mmode image.

Abstract: The method of the invention controls an ultrasound system to identify a boundary between a tissue region and a blood-filled region that lies within an ROI. The method initially administers a contrast agent to the region of interest and then transmits first and second ultrasound beams at a different power levels into the ROI. Signal returns from the first and second beams are processed to derive first and second digital values, respectively. It has been determined that, under certain circumstances, a phase change of echo returns occurs at the boundary between tissue and blood-containing contrast agent. Detection of the phase change enables precise identification of the boundary, based upon the time segment in which the phase change is detected. Accordingly, time segment values of the first and second stored digital values are then phase-compared to enable determination of a boundary location between the tissue region and the blood-filled region by detection of the phase change.

Abstract: The method of the invention controls an ultrasound system to identify a boundary between a tissue region and a blood-filled region that lies within an ROI. The method initially administers a contrast agent to the region of interest and then transmits first and second ultrasound beams at a different power levels into the ROI. Signal returns from the first and second beams are processed to derive first and second digital values, respectively. It has been determined that, under certain circumstances, a phase change of echo returns occurs at the boundary between tissue and blood-containing contrast agent. Detection of the phase change enables precise identification of the boundary, based upon the time segment in which the phase change is detected. Accordingly, time segment values of the first and second stored digital values are then phase-compared to enable determination of a boundary location between the tissue region and the blood-filled region by detection of the phase change.

Abstract: A six-stroke cycle engine burns an air-fuel charge for a first power stroke, the exhaust gases being directed to a heat regenerator located in a vapor heating chamber. A second power stroke is produced by injecting fluid directly into the heat regenerator, for generating a second power stroke with the expanded vapor, using the same engine reciprocating mechanism.

Abstract: A chord propagation velocity measurement (CPVM) system is used in connection with, for example, a brightness-mode (B-mode) or doppler ultrasound imaging system. The CPVM system monitors ultrasound data provided to it by the ultrasound imaging system and enhances the functionality of the ultrasound imaging system by providing a chord propagation velocity (CPV) associated with a body region, such as a blood vessel in a living thing. The CPV is indicative of the stiffness of the body region. In architecture, the CPVM system includes a tissue processor connected to the scanner of the ultrasound system designed to analyze each acoustic scan line and to determine a category (type of region, for example, blood or tissue) for each point along each acoustic scan line. A display produces an image generated from acoustic scan lines. A user input mechanism permits a user to identify a region of interest in the image. The tissue processor produces samples based upon the region of interest in the image.

Abstract: Apparatus and methods for controlling electrostrictive transducer sensitivity in a pulse-echo medical ultrasound system. Certain characteristics of each transducer element are tested after manufacture and recorded on a storage medium. The stored data is then used, along with certain model relations, for monitoring certain operational parameters of the transducer during use, and feedback compensation applied for maintaining the transducer sensitivity substantially constant. The parameters to be monitored may include the temperature, acoustic pressure, input power, and a figure of merit determined from the dielectric constant and coupling coefficient.

Abstract: Apparatus and methods for controlling electrostrictive transducer sensitivity in a pulse-echo medical ultrasound system. Certain characteristics of each transducer element are tested after manufacture and recorded on a storage medium. The stored data is then used, along with certain model relations, for monitoring certain operational parameters of the transducer during use, and feedback compensation applied for maintaining the transducer sensitivity substantailly constant. The parameters to be monitored may include the temperature, acoustic pressure, input power, and a figure of merit determined from the dielectric constant and coupling coefficient.

Abstract: An ultrasound display system enables a user to rapidly identify a region of interest (ROI) in a displayed ultrasound image without having to trace the outline of the ROI. The system includes a display and a processor for causing the display to manifest an ultrasound image. A user entry device enables a user to initiate a "quick ROI" identification procedure which causes the processor to superimpose a closed geometric figure on a displayed ultrasound image. The user entry device further enables adjustment of the closed geometric figure to substantially enclose the ROI. A user selection input device, in response to user actuation, causes the processor to identify the boundary of the ROI that lies within the vicinity of an edge of the closed geometric figure and further enables the processor to carry out calculations with respect to the determined ROI boundary.

Abstract: An ultrasound display apparatus provides a two-dimensional display of a fluid filled cavity and surrounding wall tissue in the form of a sequence of pixel image frames that are shown on a display screen. The apparatus includes circuitry for indicating wall tissue displacements on the screen on a frame by frame basis. The apparatus includes a pixel classification circuit for classifying pixels in each pixel image frame into two types, i.e., tissue or fluid. A frame comparator determines which pixels change classification from one to another type as between a pair of succeeding frames. A color assignment circuit assigns to changed-type pixels in a frame, a color value which causes the changed pixels to be readily differentiated by a viewing user. Different color values are used from frame to frame on both ventricular expansion and contraction cycles.

Abstract: A method and apparatus for determining the volume of a fluid-filled cavity in a patient's body in real time from an ultrasound image. An ultrasound display of the cavity and the surrounding tissue is obtained. The ultrasound display includes a sequence of ultrasound images. The user traces a fixed region of interest around the image of the cavity at the largest volume for which the volume determination is to be made. The region of interest is subdivided into a predetermined number of segments. Each pixel of the ultrasound image, at least within the region of interest, is classified as a fluid pixel or a tissue pixel. The area of fluid pixels within each segment is determined. The volume of the cavity is calculated from the area of the fluid pixels within each segment of the region of interest using the method of disks. The volume is determined for each ultrasound image in the sequence of ultrasound images to provide the volume of the cavity in real time.

Abstract: An operator adjusted lateral gain control (LGC) structure for an ultrasound imaging system, which may already include an operator adjusted time gain compensation (TGC) gain control structure. The LGC structure enables an operator to adjust the gain of one or more scan lines independently of the gain of at least one other scan line, said gain as a result of the LGC control being substantially constant along said one or more scan lines.

Abstract: A device for synchronizing the output test pattern signals of a test circuit with the clock signal of a device under test (DUT). The invention uses a programmable delay in the feedback loop of a phase locked loop system to adjust the phase of the test pattern signals to be synchronized with the clock of the device under test (DUT).