Abstract: An ultrasonic diagnosis apparatus comprises an ultrasound probe, a transmitter (including a transmitting pulse generator and a transmitting beamformer), a receiver (including a preamplifier and a receiving beamformer), a CFM processor (including a moving-element signal extractor and a velocity corrector), a tomographic image processor, and a display unit. The apparatus scans a desired section of a subject by transmitting and receiving an ultrasound pulse to and from the subject, and displays images obtained by the scanning. The velocity corrector comprises a pulsation-characterizing-velocity (velocities of a moving element) calculator, a representative velocity (reference velocity) calculator, and a corrector to correct the velocities of the moving element based on the standard velocity. The corrected velocity data is visualized on display unit. The ultrasonic diagnosis apparatus makes it possible to display the pulsatility of blood vessels in an easier and useful way.

Abstract: A medical diagnostic method, system and related equipment particularly adapted to diagnose disorders of the blood circulation serving the head and neck, and especially the brain. A preferred use of the system is early, rapid, accurate, diagnosis of stroke, especially whether the stroke is due to blockage of a blood vessel or leakage from the blood vessel.

Abstract: A tracking system for stone treatment by extracorporeal shock wave lithotripsy includes a data processing unit, a motion controller, a servo-moving platform, a stone image-processing module, a stone localization module, and a moving-mechanism control module. With the use of the stone-tracking system, the performance of an extracorporeal shock wave lithotriptor can be greatly improved, resulting in less side effect such as tissue damage.

Abstract: A volume dataset describes at least one tubular vessel and its environment. For processing the volume dataset, an operating point is first defined. A computer then determines slice planes containing the operating point and a sectional area enclosed by the vessel and contained in the respective slice plane for each of the slice planes. Finally, the computer determines the slice plane with the minimum sectional area and determines a working slice plane on the basis of this slice plane.

Abstract: The invention provides an ultrasonic monitor for measuring pulse rate values in a living subject, including a module with at least one source of ultrasonic energy, a gel pad comprised of a polymer and from about 50 to about 95% by weight of an ultrasound conductive diluent, wherein the gel pad is positioned in direct contact between the module and the living subject; an ultrasonic energy detector and associated hardware and software for detecting, calculating and displaying a readout of the measured rate values.

Abstract: An apparatus for measuring parameters preparatory to a stent replacement of an aneurytic blood vessel in a patient (26) includes a computed tomography (CT) scanner (10) that acquires image data (28) corresponding to multiple two-dimensional image slices. A reconstruction processor (32) reconstructs a three-dimensional image representation (34) from the image data (28). A tracking processor (40) produces a tracked vessel (92) including at least a centerline (80) and selected vessel boundaries (86). A user interface (44) displays a rendering (242) of the image representation to an associated user (42), measures selected vascular parameters corresponding to the stent parameters (276), and graphically superimposes the measured parameters on the rendering of the image representation (270, 272).

Abstract: Apparatuses and methods for measuring a velocity component of tissue and blood flow within a human body may generate sample data by transmitting ultrasound signals to and sampling echo signals reflected from the human body, generate frequency distribution data containing the velocity component of tissue and blood flow, extract the frequency distribution data corresponding to the velocity component of tissue flow from the frequency distribution data, and display the extracted frequency distribution data. The apparatuses and methods may also input the frequency distribution data containing the velocity component of tissue and blood flow, eliminate a direct-current component of the frequency distribution data, extract the velocity component of blood flow from the frequency distribution data, determine a maximum value of the extracted velocity component of blood flow, decide a gain level, and multiply the frequency distribution data by the decided gain level.

Abstract: The present invention provides an ultrasonic diagnostic apparatus. The ultrasonic diagnostic apparatus comprises an ultrasonic probe (1) for transmitting ultrasonic pulses into a living body and receiving ultrasonic reflected waves from the living body, a phase-detecting section (5) for detecting each phase of the ultrasonic reflected waves, and a phase-difference detecting section (6) for determining a phase difference in the repetition period of the ultrasonic transmitting/receiving operation according to the detected phase signals.

Abstract: Valvular regurgitation is assessed by identifying a characteristic regurgitation jet in a colorflow image. An M-line is placed over the region of regurgitation and Doppler M-mode information is acquired from the flow convergence region adjacent the regurgitant orifice. The Doppler M-mode information, acquired at a higher acquisition rate than the colorflow frame rate, is used to produce a measure of the regurgitant flow rate and volume through the orifice. The flow rate can be used with velocity data acquired during the regurgitation event to produce a dynamic estimate of the size of the regurgitant valve orifice.

Abstract: A method for adaptive filtering of clutter from a sample stream having a blood signal component and a clutter signal component comprises the steps of (a) estimating a signal strength of the sample stream, and (b) determining an order of a filter based on a relationship between the signal strength estimate and a signal strength threshold. The filter receives the sample stream and provides an output stream having a reduced level of the clutter signal component relative to the blood signal component.

Abstract: A method of estimating the volume flow in a vessel utilizing ultrasound techniques including the steps of imaging the vessel utilizing an ultrasonic transducer array so as to produce fluid velocity information for the vessel, the plane formed by the beams emitted by the transducers having a direction which is offset from an axis of the vessel such that the beam plane forms an elliptical section within the vessel, and utilizing the velocity information for points within the vessel and the elliptical section to calculate a mean velocity for the fluid flow through the elliptical section. The improvement of the volume flow estimation is achieved by utilizing average velocity information and Doppler signal power, and mean velocity calculation based on a weighted summation of the velocity values a multiple measurement points with weighting factors determined by the Doppler signal power at the measurement points.

Abstract: A strobed blood flow meter provides periodic measurements of blood flow velocity or volumetric blood flow over a cardiac cycle at reduced average power consumption, which is advantageous for reducing battery size, and extending device battery life, such as in an implantable application. Continuous wave Doppler, pulsed Doppler, laser Doppler, transit time, electromagnetic flow, and thermal dilution techniques are included. Strobing provides higher level excitation during active periods, which improves signal-to-noise ratio, and provides a low power standby mode during an idle time between active periods. The invention may be used for chronic or acute applications. Doppler or other signals may be telemetered from an implanted portion of the flow meter for further signal processing to extract velocity or volumetric flow. Alternatively, such signal processing is also implanted, such that the velocity signal can be telemetered to an remote monitor.

Abstract: An ultrasonic Doppler flow phantom is described which is formed of tissue-mimicking material containing a plurality of fluid flow paths through which fluid is pumped. The fluid flow paths are made of tubing and each extends over a different portion of the depth of the phantom and at a different angle. Each path is individually accessible by a probe located on the simulated skin surface at the top of the phantom, enabling the performance of the probe to be evaluated over a wide range of depths from shallow to very deep and over several flow angles.

Abstract: An ultrasonic imaging system uses a specially configured scanhead to provide ultrasound return signals that are processed by an imaging unit to generate a three-dimensional Doppler ultrasound image. One embodiment of the scanhead includes a first pair of apertures aligned along a first axis, and a second pair of apertures aligned along a second axis that is perpendicular to the first axis. All of the apertures lie in a common plane. Respective signals from the apertures along each axis are processed to generate two-dimensional Doppler motion vectors. The resulting pairs of two-dimensional Doppler motion vectors are then processed to generate three-dimensional Doppler motion vectors that are used to generate a three-dimensional Doppler image. In another embodiment, three co-planar apertures are arranged equidistantly from each other about a common center, and the three-dimensional Doppler image is generated from respective signals from the apertures.

Abstract: Techniques are provided for obtaining selected instantaneous area measurements for a dynamic orifice through which blood is flowing in at least one direction, for obtaining instantaneous flow rates of blood passing through such a dynamic orifice and for obtaining flow volume for blood passing through a dynamic orifice. All of these techniques involve ensonifying a thin sample volume of blood flow exiting at the orifice, which volume is in a region of flow which is substantially laminar, such region normally being the vena contracta for the orifice, with an ultrasonic pulsed Doppler signal, receiving backscattered signal from blood within the sample volume and forming a power-velocity spectrum from the received backscattered signal. Techniques are disclosed for assuring that only laminar flow is looked at in forming the power-velocity spectrum.

Abstract: A method for adaptive filtering of clutter from a sample stream having a blood signal component and a clutter signal component comprises the steps of (a) estimating a signal strength of the sample stream, and (b) determining an order of a filter based on a relationship between the signal strength estimate and a signal strength threshold. The filter receives the sample stream and provides an output stream having a reduced level of the clutter signal component relative to the blood signal component.

Abstract: An ultrasound imaging system provides for high density scanning (transmit/receive) of color flow signals. The ultrasound scan sequence of each transmitted and received color flow ultrasound beam is laterally spaced through the imaging field to calculate flow velocities. The color flow beams are transmitted and received only once at each position along the horizontal scanning axis of the imaging field. The scanning technique of the present invention enables a large number of color flow lines to be acquired while keeping a high frame rate. The color line density is comparable to that of a B-mode image. A method of high-speed calculation or a high-speed autocorrelation is also provided to process the greater number of signals generated by the present scanning technique. A time-sharing scanning technique between color flow and B-mode images is also provided to synchronize blood flow and tissue (B-mode) images together.

Abstract: Disclosed is ultrasonic medical probe (10) connectable to a Doppler signal generator and processor for detecting or measuring blood flow in a vessel. In one embodiment, the distal portion (52) of the probe comprises an outer sheath (17) that includes a malleable shapeable portion (16), such as an annealed stainless steel cannula, to which a transducer head (11) containing one or more ultrasonic transducers (12), is mounted distally. Two wires (14, 15), comprising the electrical conductor (13), extend through the outer sheath from each ultrasonic transducer to a proximal connector (19). The shapeable portion can be contoured before or during a procedure, such as to access the natural spaces within brain to read flow in a cerebral artery.

Abstract: The present invention relates to a method and associated apparatus for improving the accuracy with which the speed of a fluid, such as a liquid, in particular blood flowing in a duct, such as a blood vessel, in particular the aorta, is measured by means of a signal emitted by a Doppler transducer (4). In characteristic manner, according to the method, the Doppler transducer is associated with a programmable memory (50) which contains at least one correction data item for correcting the Doppler signal transmitted by the transducer (4) to a transducer control and computer unit (8). Said computer unit (8) incorporates said signal correction data item in its computation (at 16) of each speed measurement on the basis of each signal emitted by the Doppler transducer, and it computes the speed value while taking account of said correction data item so as to provide a corrected measurement of the speed of said fluid, thereby improving its accuracy.

Abstract: A method to measure spatial fluid flow components and their velocity profiles in a number of locations in a cross-sectional area of a lumen or other body cavity by using ultrasound in which the cross-sectional area is interrogated by a plurality of ultrasonic beams; the estimation of the spatial flow components is obtained from a combination of estimations of axial, lateral and total flow; the estimation of one or more flow components is obtained through any combination of time-shift and decorrelation analysis of two or more beam-signals of the interrogating ultrasound transducer; and the estimation accuracy is further improved by the use of a reference decorrelation curve obtained from experiments or beam-theory or both.

Abstract: A system and methods for measuring the volume flow of fluid in an enclosed structure with an ultrasound system is provided. Manual designation of flow angles and areas may not be necessary. Velocities along two or more different scan lines in a first scan plane are obtained to determine an angle of flow within the enclosed structure. A Doppler spectrum parameter is measured from a transmission in a second scan plane substantially perpendicular to the first scan plane. Volume flow is calculated from the flow angle and the parameter. The scan planes are associated with rotating a linear array transducer or holding a multi-dimensional transducer in place. A C-scan method with a linear transducer may also be used.

Abstract: The present invention relates to a method and associated apparatus for improving the accuracy with which the speed of a fluid, such as a liquid, in particular blood flowing in a duct, such as a blood vessel, in particular the aorta, is measured by means of a signal emitted by a Doppler transducer (4). In characteristic manner, according to the method, the Doppler transducer is associated with a programmable memory (50) which contains at least one correction data item for correcting the Doppler signal transmitted by the transducer (4) to a transducer control and computer unit (8). Said computer unit (8) incorporates said signal correction data item in its computation (at 16) of each speed measurement on the basis of each signal emitted by the Doppler transducer, and it computes the speed value while taking account of said correction data item so as to provide a corrected measurement of the speed of said fluid, thereby improving its accuracy.

Abstract: A blood viscosity measuring system and method that monitors the rising head of a column of fluid representing a living being's blood in-vivo to determine the blood viscosity over a range of shears. The system includes a capillary tube, at least a portion of which is located within the vascular system of the being, and a riser tube, having a liquid therein coupled to the capillary tube. A sensor and associated microprocessor are provided to determine the change in the height of the liquid in the riser tube at plural points along the length of the tube from which the viscosity is calculated. The system can be utilized to determine the deformability of the red blood cells of a living being's blood and/or the thixotropic properties of a living being's blood. Use of the system enables one to screen a material, e.g., a pharmaceutical, on a test subject, such as a living human being or laboratory animal, to determine the likely effect of the material in altering a parameter of the blood, e.g.

Abstract: The invention features an acoustic medical device for making Doppler measurements and imaging within a body fluid conduit using a single-transducer. The device has an elongated device body, defining a device axis, constructed for positioning a distal end of the device body near a region of interest in the body fluid conduit. Disposed within the device body is an ultrasonic beam directing assembly that is constructed to direct a portion of ultrasonic energy from a single transducer in a direction for imaging within the body fluid conduit and to direct another portion of the ultrasonic energy in a direction for making Doppler measurements within the body fluid conduit.

Abstract: The cardiac ejection fraction EF is estimated based on the parameters of a model of an indicator (such as thermal) dilution through the heart. A channel model is defined by an upstream indicator injector, such as a heater, positioned preferably in the right atrium/ventricle and a downstream indicator concentration sensor, such as a thermistor. The preferred model is a lagged normal transfer function, which has as one of its output parameters the indicator decay constant .tau. of the blood channel. The heart rate HR is also measured. The ejection fraction EF is then calculated continuously as EF=1-exp(-60/(.tau.*HR)). The cardiac output CO is also estimated in the model, preferably based on an estimate of the zero-frequency gain of the lagged normal transfer function. End diastolic volume EDV is then also calculated continuously as a function of CO, HR and EF.

Abstract: A probe includes a handle, neck, and sensor head. The neck consists of a stiff portion and a flexible portion. The neck is offset from the handle so that a hand of a surgeon holding the handle does not block the surgeon's view of sensor head. In another embodiment, the stiff portion includes three sections that have separate and distinct linear axes. The extended axis of the section adjacent the handle intersects the juncture of the flexible portion and the stiff portion of the neck, while the sensor head is connected to the flexible portion of the neck. The precise alignment of the handle and neck enables the precise placement of the sensor head around a small blood vessel.

Abstract: In an ultrasound system and method, a transducer connects to an estimator for obtaining first and second blood flow parameters associated with first and second scan line directions, respectively, in a first scan plane. One beam substantially covering a cross-sectional area of a tubular structure (uniform insonification) or a plurality of beams may be used. A first area associated with the cross-section of the tubular structure is also estimated from the blood flow parameters. The process is repeated for a plurality of scan planes. A processor determines the cross-sectional area of the tubular structure perpendicular to its axis (a second area), the average velocity of flow parallel to the axis, and the volume flow as a function of the first area and the first and second blood flow parameters of all the scan planes. For real-time volume flow, the orientation of the tubular structure is determined using the second area and the first and second blood flow parameters.

Abstract: An ultrasonic echography system includes a probe (1) which is connected to an echograph provided with a transmission stage (32), receiving and processing stages (34, 38) for ultrasonic echo signals, and a device (21) for displaying images of an artery. The probe (1) is formed by three integral transducers, i.e. a first, central transducer (2) for scanning the artery axially and two lateral, further transducers (3, 4) which are arranged parallel to one another and oriented perpendicularly to the first transducer in order to form transversal sectional images of the artery. The echograph also includes a sequence for sequentially activating each of the three transducers in a cyclical manner.