Frequency is swept in acoustic radiation force impulse (ARFI) scanning. Different frequencies are used at different times during the ARFI. For example, different frequencies are focused to different depths in the ARFI transmit beam. Since the frequency sweep is used for the ARFI pushing pulse rather than a transmit pulse for which echoes are received, the rate of change of the frequency is not dictated by the speed of sound. The rate of change of the frequency may be adjustable or set based on other factors, such as the type of tissue. In combination with a time varying focal position, the frequency sweep may better compensate for loss as compared to a focus sweep alone. The frequency sweep may better compensate for loss as compared to a single point focus ARFI.

A transducer is provided, which includes an oscillator and a broadbanded matching circuit. In the oscillator, a peak frequency corresponding to a peak transmission sensitivity may separate from a center frequency in a given bandwidth, and a transmission sensitivity may increase as a frequency separates from the peak frequency with respect to the center frequency. The broadbanded matching circuit may be configured to perform an impedance matching so that the transmission sensitivity of the oscillator at the peak frequency becomes substantially equal to the transmission sensitivity of the oscillator at the center frequency.

Disclosed is a method for operating an ultrasonic diagnostic apparatus. The method includes transmitting separate first and second ultrasonic signals to an object, receiving a first echo signal which corresponds to the first ultrasonic signal and a second echo signal which corresponds to the second ultrasonic signal, separating the received first and second echo signals in order to generate first ultrasonic data which corresponds to the first echo signal and second ultrasonic data which corresponds to the second echo signal, and displaying a first ultrasonic image which is generated based on the first ultrasonic data and a second ultrasonic image which is generated based on the second ultrasonic data. The first ultrasonic image is an ultrasonic image of a first cross-sectional surface of the object, and the second ultrasonic image is an ultrasonic image of a second cross-sectional surface of the object.

An ultrasound system (1) is disclosed that comprises a probe (10) including an array (110) of CMUT (capacitive micromachined ultrasound transducer) cells (100), each cell comprising a substrate (112) carrying a first electrode (122), the substrate being spatially separated from a flexible membrane (114) including a second electrode (120) by a gap (118); and a bias voltage source (45) coupled to said probe and adapted to provide the respective first electrodes and second electrodes of at least some of the CMUT cells with a monotonically varying bias voltage including a monotonically varying frequency modulation in a transmission mode of said probe such that the CMUT cells are operated in a collapsed state and transmit at least one chirped pulse during said transmission mode. Such a system for instance may be an ultrasound imaging system or an ultrasound therapeutic system. An ultrasonic pulse generation method using such as system is also disclosed.

An ultrasound imaging system, a method for ultrasound imaging and a non-transitory computer readable medium that stores instructions executable by one or more processors to perform the method for ultrasound imaging are presented. The method includes convolving one or more base ultrasound pulses corresponding to a particular frequency with a desired code to generate an extended excitation wave. Further, the extended excitation wave is transmitted to a broadband ultrasound transducer to be transmitted towards the target. Subsequently, echo signals reflected back from the target in response to the extended excitation wave are received and de-convolved. One or more ultrasound images of the target corresponding to multiple frequencies are generated based on the de-convolved echo signals.

Methods, systems, and apparatuses are disclosed for ultrasound imaging comprising Time Delay Spectrometry. A frequency swept signal can be transmitted through a medium, such as human tissue. The signal can be a low-voltage signal (e.g., 0 volts to 5 volts peak-to-peak) transmitted for long duration (e.g., 20 milliseconds) at various frequencies. As the signal propagates through the medium it can be reflected and delayed. A delay associated with the signal the can cause a change in the associated frequencies. The signal can be filtered to retain only frequencies in an audio frequency range. The signal can be beamformed and processed to produce an image.

An ultrasonic signal processing method and apparatus (30), a computer device (50) and a storage medium. The method includes: acquiring a target ultrasonic signal of a dynamic broadband corresponding to target tissue (101); determining, according to the target ultrasonic signal, an acoustic characteristic parameter of the target tissue (102); performing assessment processing to the target tissue according to the acoustic characteristic parameter of the target tissue (103). The acoustic characteristic parameter of the target tissue is determined according to the target ultrasonic signal of the dynamic broadband corresponding to the target tissue, and the assessment is performed to the target tissue based on the acoustic characteristic parameter of the target tissue, and ultrasonic signals of the target tissue at multiple frequencies are comprehensively considered, so that signal components are varied, thereby improving accuracy of the assessment to the target tissue.