Abstract: An ultrasonic diagnostic system for measuring fluid flow velocities through Doppler techniques is provided which eliminates the effects of tissue motion from fluid flow velocity information. In a preferred embodiment Doppler information signal are discriminated to determine the presence of signal components resulting from moving tissue, which signal components are located at frequencies of a Doppler spectrum other than the predetermined frequency location of stationary tissue signals. The tissue motion signal components present are shifted to the predetermined frequency location and removed by high pass filtering the Doppler signals. The remaining signals are then shifted back to their original frequency location and transmitted to a Doppler velocity estimator for further processing of the fluid flow velocity information and ultimate display of the information.

Abstract: A technique for increasing the display frame rate of a medical ultrasound imaging system. The system receives trigger signals, each based upon the occurrence of a predetermined event in a subject's cardiac cycle, such as an R-wave. In one technique, in response to each trigger signal, the ultrasound system acquires a series of frames, each frame comprising data representing an image of a portion of the subject's body at an associated acquisition time. A frame time is determined for each frame, each frame time being the time from the preceding trigger signal to the acquisition time for the frame. Two or more frame series are then played back in order of increasing frame times, thereby producing a display frame rate higher than the acquisition frame rate.

Abstract: A system for imaging a biopsy needle with ultrasound is shown in which the needle tip elicits a Doppler response through controlled reciprocation of the needle tip. In a preferred embodiment the biopsy needle includes a hollow cannula which carries a removable stylet. Means for reciprocating the stylet is coupled to the proximal end of the stylet, and the distal tip of the stylet is reciprocated at the distal end of the cannula. This motion is detected through Doppler interrogation of the body region at which the biopsy is to be performed, and the Doppler response of the needle tip in the image of the body region allows the needle tip to be monitored as it approaches the tissue to be biopsied.

Abstract: Ultrasonic apparatus for use in detecting an object having a transducer. The transducer has an array of at least one element coupled directly into air. The apparatus also includes a transmitter which may be multi-channel, a receiver which may be multi-channel, a transmit receive switch, and a computer for causing operation of said transmit receive switch to cause sequential supplying of pulses of energy from the transmitter to the element or elements of the transducer and for receiving energy received by the transducer. The element or elements of the transducer are provided with a roughened surface to produce high frequency ultrasonic energy.

Abstract: A Doppler blood velocity measuring device is described which includes anti-aliasing circuitry. The anti-aliasing circuitry is based upon the use of a multigate Doppler unit which receives Doppler shift frequency information from various depth ranges. Thereafter, the Doppler frequencies received are corrected by adding a correction frequency to the perceived Doppler frequency with the correction frequency selected based on the assumption that blood flow velocity cannot change drastically between adjacent depths.

Abstract: The apparatus described unaliases a Doppler signal which is related to the velocity of blood flowing in a sample volume. It then generates an audio output corresponding to the unaliased Doppler signal. The device generates an unaliased, instantaneous signal which corresponds to the Doppler frequency associated with the blood velocity in the sample volume. That unaliased instantaneous frequency is fed into programmable read only memories (PROMs) which provide digitized values for the sine and cosine functions. Those values are fed into digital-to-analog converters, and they are scaled to provide audio outputs.

Abstract: The device uses two Doppler receivers having different center frequencies. After the mean Doppler frequency of each receiver is determined, one of the mean Doppler frequencies is subtracted from the other one of the mean Doppler frequencies, thereby providing the mean Doppler frequency associated with a frequency which is equal to the difference between the two original frequencies.