38 results about "Peak velocity" patented technology

A medical ultrasound viewing system for processing a sequence of three-dimensional (3-D) ultrasound images far performing a quantitative estimation of a flow through a body organ comprising means for performing steps of acquiring a sequence of 3D color flow images, of said flow; assessing the flow velocity values in the 3D images, constructing isovelocity surfaces (6) by segmentation of the flow velocity values; computing the volume (Vol) delimited by the isovelocity surfaces; and using the flow velocity value (V) and the volume (Vol) computed from a segmented surface for computing the surface of an orifice (3) of the organ through which the flow propagates. The viewing system further comprises means for performing steps of measuring the peak velocity (VREG) of said flow through said orifice; computing the surface of the orifice (SOR) through which the flow propagates as a function of the flow velocity value (V) at an isovelocity surface upstream the flow propagation with respect to said orifice, the volume (Vol) computed from said segmented isovelocity surface, and the peak velocity of the flow through said orifice. The surface is given by the formula: SOR=Vol. V / VREG. The system can be applied to the assessment of the surface of regurgitation of the mitral jet.

A system and method for measurement of flow parameters in a sewer pipe that may be partially or completely filled. Flow parameters may include flow velocity, flow volume, depth of flow and surcharge pressure. Measurements are taken from a sensor head installed on the inside of the pipe at the top of the pipe approximately the larger of at least 1 foot or 1 pipe diameter upstream of a pipe opening. Flow velocity may be measured by two different technologies. The technology employed depends on whether or not the pipe is full. If the pipe is not full then flow velocity may be measured, for example, using a wide beam, ultrasonic, diagonally downward looking Doppler signal that interacts with the surface of the flow. If the pipe is full, then flow velocity may be measured using, for example, an average velocity Doppler sensor, a peak velocity Doppler sensor or an ultrasonic velocity profiler.

The present invention relates to a system and method for measurement of flow velocity using the transmission of a sequence of coherent pulsed ultrasonic signals into the flow, and sampling the received response signal at a predetermined delay time relative to the pulse transmission that does not correspond to the signal transmission time. The sampling may be coherent with a frequency offset from the coherency frequency of the pulses. The received signal samples are then spectrally processed, typically by a Fourier process, to generate a frequency domain data set. A threshold technique is used on the frequency domain data set to determine a peak Doppler shift. Average velocity is then obtained by multiplying the peak Doppler shift by a factor, for example, 0.90. In one embodiment, the transmit pulse and receive samples are interleaved by alternating between transmitting a pulse and, after a delay, sampling the received signal.

A seek operation is performed by identifying a seek length of the seek operation and selecting a representation of a deceleration position-velocity profile based on the seek length. Successive demand velocity values are selected during the seek operation by identifying a distance-to-go and a distance-traveled of the seek length, calculating a representation of an acceleration demand velocity based on the identified distance-traveled and a representation of an acceleration position-velocity profile, identifying a representation of a deceleration demand velocity based on the identified distance-to-go and the selected representation of a deceleration position-velocity profile, and selecting the representation of either the acceleration demand velocity or the deceleration demand velocity. The representation of acceleration demand velocity is preferably performed by using a first scaling factors based on the seek length to adjust the identified distance-traveled, and using a second scaling factor based on the seek length to adjust a representation of a demand velocity of a normalized position-velocity profile.

A method and an apparatus for performing pulsed-wave spectral Doppler imaging at every color flow range gate location in a two-dimensional (or three-dimensional) region of interest. Spectral processing is necessary to determine the flow parameters. Performing this processing at every color flow range gate location creates the two-dimensional image. The method generates two-dimensional images of flow parameters such as peak velocity, pulsatility index, resistance index, etc. With the two-dimensional image, the user immediately observes where the most critical value of the flow parameter occurs and what that value is.

A medical ultrasound viewing system for processing a sequence of three-dimensional (3-D) ultrasound images far performing a quantitative estimation of a flow through a body organ comprising means for performing steps of acquiring a sequence of 3D color flow images, of said flow; assessing the flow velocity values in the 3D images, constructing isovelocity surfaces (6) by segmentation of the flow velocity values; computing the volume (Vol) delimited by the isovelocity surfaces; and using the flow velocity value (V) and the volume (Vol) computed from a segmented surface for computing the surface of an orifice (3) of the organ through which the flow propagates. The viewing system further comprises means for performing steps of measuring the peak velocity (VREG) of said flow through said orifice; computing the surface of the orifice (SOR) through which the flow propagates as a function of the flow velocity value (V) at an isovelocity surface upstream the flow propagation with respect to said orifice, the volume (Vol) computed from said segmented isovelocity surface, and the peak velocity of the flow through said orifice. The surface is given by the formula: SOR=Vol. V / VREG. The system can be applied to the assessment of the surface of regurgitation of the mitral jet.

Techniques are provided for evaluating mechanical dyssynchrony within the heart of patient in which a pacemaker, implantable cardioverter-defibrillator (ICD) or other medical device is implanted. In one example, a set of cardiogenic impedance signals are detected along different sensing vectors passing through the heart of the patient, particularly vectors passing through the ventricular myocardium. A measure of mechanical dyssynchrony is detected based on differences, if any, among the cardiogenic impedance signals detected along the different vectors. In particular, differences in peak magnitude delay times, peak velocity delay times, peak magnitudes, and waveform integrals of the cardiogenic impedance signals are quantified and compared to detect abnormally contracting segments, if any, within the heart of the patient. Warnings are generated upon detection of any significant increase in mechanical dyssynchrony. Diagnostic information is recorded for clinical review. Pacing therapies such as cardiac resynchronization therapy (CRT) can be activated or controlled in response to mechanical dyssynchrony to improve the hemodynamic output of the heart.

A second stage external jet nozzle mixer (20) includes identically formed lobes which equal in number the lobes of the first stage internal mixer. The external mixer works with the internal mixer, and furthers the mixing of the jet engine internal bypass flow with the internal jet engine core flow. This mixing levels the disparate flow velocities attendant with the jet engine exhaust, reduces the peak velocities from the jet engine core and increases the lower bypass velocities of the jet engine internal bypass flow. The lobes include complex curvatures that greatly enhance mixing of the gases and ambient cooling air, and thereby reduce noise. At the lobe terminus, the lobe dimensional characteristics may be adjusted to thereby adjust the total terminus area to achieve a match to a jet engine to cause that jet engine to run at a determined RPM and noise level. Noise attenuation may also be adjusted by changing lobe dimensions. Prior existing second stage exhaust jet nozzle mixers may be retrofitted to allow alteration of their total terminus area by employing the disclosed device and method.

Optical Coherence Tomography (OCT) is a high-resolution, non-invasive technique to image subsurface tissue and tissue functions. A broadband light source illuminates an object and the reflected photons are processed using an interferometer, demodulated into inphase and quadrature components and then digitized. The captured data contains information about the velocity of the moving scatterers but current Doppler estimation algorithms have a limited velocity detection range. Using a two dimensional velocity estimation, Doppler OCT (DOCT) can be used for the detection of in vivo aortic blood flow rates of over 1 m / s peak velocity through an esophageal DOCT probe. Previous methods have used a transverse Kasai (TK) autocorrelation estimation to estimate the velocity which is good for slow velocities, such as in the microvasculature. By calculating the Kasai autocorrelation with a lag in the depth or axial direction, backscattered frequency information is obtained which yields high velocity rate information. Through subtraction with stationary backscattered information, the Doppler shift is obtained by the axial Kasai (AK) technique. Through utilizing information from two dimensions, velocities can be resolved which spans rates from the microcirculation to cardiac blood flow velocities.

A system and method for determining a subject's level of fatigue. The method includes measuring microsaccadic eye movement dynamics of the subject, calculating a current microsaccade peak velocity from the measured microsaccadic eye movement dynamics, and comparing the current microsaccade peak velocity to a baseline microsaccade peak velocity. The method further includes determining the level of fatigue based on a difference between the current microsaccade peak velocity and the baseline microsaccade peak velocity.

A method is described for recognizing fatigue, the method comprising an ascertaining step, a determining step, and a comparing step. In the ascertaining step a first saccade and at least one further saccade of an eye movement of a person are ascertained using a gaze direction signal that models the eye movement. In the determining step, a first data point representing a first amplitude of the first saccade and a first peak velocity of the first saccade, and at least one further data point representing a further amplitude of the further saccade and a further peak velocity of the further saccade, are determined using the gaze direction signal. In the comparing step, the first data point and at least the further data point are compared with a saccade model. The person is recognized as fatigued if the data points have a predetermined relationship to a confidence region of the saccade model.

A system improves accuracy of blood flow peak velocity measurements as well as the speed and precision of an MR data acquisition workflow. A system for blood flow velocity determination in MR imaging comprises an MR imaging system. The MR imaging system acquires a three dimensional (3D) MR imaging dataset of a patient anatomical volume of interest and a one dimensional (1D) MR imaging dataset within the volume of interest automatically aligned in response to 3D vector directional information. An image data processor derives the 3D vector directional information by, deriving velocity magnitude data using the acquired 3D MR imaging dataset, identifying maximum velocity data using the derived velocity magnitude data and transforming the identified maximum velocity data to provide the 3D vector directional information. A calculation processor uses the acquired 1D MR imaging dataset to calculate a blood flow velocity in a direction determined by the 3D vector directional information.