Abstract:
A method for compensating for inoperative transducer elements in an ultrasound transducer. The transmit voltage of the driving signals applied to transducer elements that are adjacent an inoperative element is increased to compensate for the inoperative element. Preferably, a linear interpolation used whereby the power/gain of the signals to be applied to the inoperative element is divided equally among the adjacent operative elements. If an inoperative transducer element is adjacent more than one inoperative element, then the gain of the operative transducer element is increased accordingly for each such inoperative element. In addition, the gain of the echo signals produced by the adjacent transducer elements is increased to compete for the inoperative element.
Abstract:
A method for increasing the valid data points produced by a digital filter. Input data is applied to a pair of filters that produce transients in response to different input data values. Output data from each of the filters is then combined to produce a data set with no transients. In one embodiment, the pair of filters have the same impulse response but the input data is applied to one filter in a first direction and to the other filter in an opposite direction. In another embodiment, the input data is applied to both filters in the same direction but the filters have inverted impulse responses. The present invention is particularly useful for minimizing a gap created when an ultrasound system alternates between different imaging modes. In addition, the present invention, can be used to increase the number of valid data points that are analyzed during color flow ultrasound imaging.
Abstract:
A BcD mode ultrasound imaging system including a Doppler processor which is configured to receive a Doppler signal having components that are corrupted by residue from color mode interleaving. The Doppler processor is configured to analyze the residue effect and compensate for the residue by filtering the received Doppler signal.
Abstract:
An ultrasound system creates ultrasound images at faster frame rate by eliminating ultrasonic transmissions along every beam line. Preferably, ultrasound images are created by alternately transmitting ultrasonic signals on the even and odd transmit beam lines. Parallel beam forming is used where transmissions along a single transmit beam line create echo signals on a pair of receive beam lines. To eliminate the artifact caused by the round-trip beam line sensitivities, echo signals created in response to transmissions along the even transmit beam lines are averaged with echo signals created in response to transmissions on the odd transmit beam lines. The averaged echo signals are used to create an ultrasound image without artifacts.
Abstract:
An ultrasound system (50) estimates the speed of sound in the tissue (60) under examination. The ultrasound system obtains a series of test images (150) using different estimates of the speed of sound in the body tissue. For each image produced, the ultrasound system computes a function that is indicative of image quality for one or more regions of interest (152) in the test image. The image quality function exhibits a minimum or maximum when computed for a region of interest obtained at a speed of sound substantially equal to a true speed of sound in the tissue. The ultrasound system selects the test image having the minimum or maximum function value and obtains subsequent images of the tissue using the speed of sound used to obtain the test image selected.
Abstract:
This invention addresses the aliasing and range ambiguity artifact trade-off occurring in pulsed doppler ultrasound applications. By increasing pulse repetition frequency to avoid aliasing and by implementing non-coinciding transmit and receive beam-patterns, range ambiguity effects are reduced. Separate transmit and receive apertures define respective transmit and receive beam-patterns. These separate transmit and receive beam-patterns intersect at a primary range gate. Secondary range gates may occur along the receive beam-pattern. The transmit beam-pattern does not intersect such secondary gates. Weaker dispersed ultrasound energy may intersect the secondary gates, however, and reflect back to the receive aperture. Relatively stronger samples are obtained from the primary range gate than from the secondary range gates. In effect the geometry of the transmit and receive beam-patterns maximizes the strength of the response from the primary gate and reduces the strength of the response from the secondary gates.