Abstract: The ultrasound transducer array defines an average row spacing along the elevation for receiving transducer elements that differs from an average row spacing along the elevation for transmitting transducer elements. In one embodiment a relatively "coarse" row spacing is used for reception and a relatively "fine" row spacing is used for transmission. The differing spacings lead to different transmit-elevation and receive-elevation beam-patterns. In one configuration the number of transducer elements, and correspondingly the number of ultrasound processing channels, is reduced. In an alternative configuration the beam-pattern "footprint" is increased without increasing the number of transducer elements or processing channels. The array includes dedicated transmit-only elements and/or dedicated receive-only elements, together with coincident, time-shared transmit/receive elements.

Abstract: A vibratory energy (ultrasonic) imaging system of the type including a transducer array having a plurality of transducer elements for generating pulses of vibratory energy which are directed towards reflectors and which receive reflections of said vibratory energy and develop echo signals in response thereto. The array comprises a two-dimensional array of transducer elements arranged in a plurality of rows extending in a lateral dimension of the array and a plurality of columns extending in an elevation dimension of the array, at least one of a first type of said columns having elements of a first height in the elevation dimension and at least one of a second type of column having elements of a second height in the elevation dimension which is greater than the first height. In a preferred embodiment of the invention, the first height is an integral fraction of the second height.

Abstract: An ultrasound imaging system of the type including a 2D transducer array which has first and second types of transducer elements. Each element of the first type occupies an area of the array which is an integral fraction of the area occupied by each element of the second type. A connection arrangement comprising a plurality of multiplexer/summation circuits is provided for electrically connecting the array elements to the remainder of the ultrasound imaging system. Each multiplexer/summation circuit has a plurality of signal inputs individually connected to a respective plurality of the elements of the first type for selectively combining a given number of the elements of the first type together, the given number being an inverse of the integral fraction.

Abstract: This disclosure relates to a noninvasive means for detecting, counting and characterizing emboli moving through the arterial or venous circulation. An ultrasonic transducer is applied to the skin or other tissues of the subject at sites such as over the temporal bone on either side of the head of the subject, on the neck, on the chest, the abdomen, arm, leg, within the esophagus, or surgically exposed organs or blood vessels. Using standard ultrasonic Doppler techniques, Doppler-shifted signals are located which are proportional to the blood flow velocity in the blood vessel(s) of interest. Spectral analysis is performed on the received signal using the fast Fourier transform or other appropriate technique to determine the frequency components in the Doppler shift spectrum. Further analysis of the spectra is used to delineate and characterize Doppler shift signals due to blood from Doppler shift signals due to emboli having a variety of compositions.

Abstract: A cardiac output measurement device for the real-time, non-invasive measurement of cardiac output that can be effectively operated by relatively unskilled personnel on a routine monitoring basis in a wide variety of office and hospital conditions. To accomplish this task, the system utilizes a pulsed Doppler ultrasound transducer directed through the suprasternal notch of a patient axially towards the blood flow in the ascending aorta. The device automatically searches the ascending aorta at various predetermined depths to find the depth at which the greatest quality blood velocity reading is detected. An examination is performed at that chosen depth and the device automatically calculates a patient's cardiac output from the Doppler measured velocity combined with an aortic diameter estimation made from the patient's height, weight, and age. The device automatically calculates cardiac velocity, cardiac index, stroke distance, heart rate, and stroke volume.

Abstract: The present invention relates to an apparatus which determines the distribution of the attenuation slope coefficient on a real-time basis using the center frequency shift. In one embodiment, the phase difference between a received signal and a reference signal is determined using EXCLUSIVE OR gates or an inverse trigonometric relation stored in a ROM. The phase difference is input to a differentiator which outputs the center frequency shift of the received signal on a real-time basis. The center frequency shift is input to another differentiator which outputs the attenuation slope coefficient. In other embodiments, the received signal is distributed into received signal bands, having different center frequencies, and signal characteristics of the received signal bands are averaged to remove virtually all effects of spectrum scalloping in the time domain. Thus, the attenuation slope coefficient is obtained without the effects of spectrum scalloping using simple hardware and without Fourier transformation.

Abstract: The present invention relates to an apparatus which determines the distribution of the attenuation slope coefficient on a real time basis using the center frequency shift. The phase difference between a received signal and a reference signal is determined using EXCLUSIVE OR gates or an inverse trigonometric relation stored in a ROM. The phase difference is input to a differentiator which outputs the center frequency shift of the received signal on a real time basis. The center frequency shift is input to another differentiator which outputs the attenuation slope coefficient. Thus, the attenuation slope coefficient is determined using simple hardware and without calculating the power spectrum and the first moment.