Disclosed is an imaging method for producing an image of a region inside a medium by an array of transducers, including the a transmission step of a plurality of waves inside the medium, a reception step for acquiring a set of data, a beamforming step providing a plurality beamformed pixel values depending on various transmit weighting vectors, and a combining step for combining the beamformed pixel values into a pixel value of each pixel in the image. The transmit weighting vectors are different and orthogonal one to another one.

Because of the increase of the obesity related diseases, it is desirable to be able to detect a fatty liver and quantify the content in fat for the fatty liver. Known methods are biopsy and magnetic resonance imaging. However, biopsy is an invasive method and magnetic resonance imaging is a complicated method to carry out. The inventors propose a new ultrasonic method, which is more compliant with a regular control of the content in fat for the fatty liver for a subject. This method notably relies on a smart exploitation of the coherence properties of ultrasound pulses applied to the liver. This method has already been validated on sane subjects as providing accurate measurements, notably for fat content.

Because of the increase of the obesity related diseases, it is desirable to be able to detect a fatty liver and quantify the content in fat for the fatty liver. Known methods are biopsy and magnetic resonance imaging. However, biopsy is an invasive method and magnetic resonance imaging is a complicated method to carry out. The inventors propose a new ultrasonic method which is more compliant with a regular control of the content in fat for the fatty liver for a subject. This method notably relies on a smart exploitation of the coherence properties of ultrasound pulses applied to the liver. This method has already been validated on sane subjects as providing accurate measurements, notably for fat content.

A coherence indicator of received signals is calculated for pixels with a small amount of calculation, and a high-quality ultrasound image is obtained. A plurality of types of images in which a sound speed for beamforming is changed into a plurality of types are generated. By arranging, in order of the sound speed for beamforming, signal intensities of the pixels at corresponding positions between the plurality of types of images, a change in signal intensities in a direction of the sound speed for beamforming is obtained. A coherence indicator representing coherence of the received signals used for beamforming of the pixels is calculated based on the obtained change in the signal intensities.

An ultrasound imaging system which uses multiline receive beamforming for synthetic transmit focusing are phase adjusted to account for speed of sound variation in the transmission medium. The phase discrepancy of the received multilines caused by speed of sound variation in the medium is estimated in the frequency domain for both the transmit angular spectrum and the receive angular spectrum. The phase variation is removed in the frequency domain, then an inverse Fourier transform is used to transform the frequency domain results to the spatial domain. In another implementation, the phase discrepancy of the received multilines is estimated and corrected entirely in the spatial domain.

Methods and systems are provided for receiving beamforming of ultrasound signals to generate ultrasound images with increased resolution. In one example, a method includes calculating a respective beamforming quality metric for each of a plurality of beamforming sound speeds, each beamforming quality metric calculated on ultrasound receive channel signals time-delayed based on a respective beamforming sound speed, identifying a target beamforming sound speed based on the beamforming quality metrics, and generating an ultrasound image using the target beamforming sound speed.

Methods and systems are provided for receiving beamforming of ultrasound signals to generate ultrasound images with increased resolution. In one example, a method for an ultrasound system including a plurality of ultrasound transducers each coupled to a respective receive channel includes time-delaying a set of ultrasound receive channel signals to form a plurality of time-delayed sets of ultrasound receive channel signals, each time-delayed set of ultrasound receive channel signals time-delayed based on a different beamforming sound speed, calculating a beamforming quality metric for each receive channel and for each time-delayed set of ultrasound receive channel signals, and generating an ultrasound image from ultrasound receive channel signals selected from the plurality of time-delayed sets of ultrasound receive channel signals based on each beamforming quality metric.

A Multiple Aperture Ultrasound Imaging system and methods of use are provided with any number of features. In some embodiments, a multi-aperture ultrasound imaging system is configured to transmit and receive ultrasound energy to and from separate physical ultrasound apertures. In some embodiments, a transmit aperture of a multi-aperture ultrasound imaging system is configured to transmit an omni-directional unfocused ultrasound waveform approximating a first point source through a target region. In some embodiments, the ultrasound energy is received with a single receiving aperture. In other embodiments, the ultrasound energy is received with multiple receiving apertures. Algorithms are described that can combine echoes received by one or more receiving apertures to form high resolution ultrasound images. Additional algorithms can solve for variations in tissue speed of sound, thus allowing the ultrasound system to be used virtually anywhere in or on the body.

In an ultrasound imaging system which produces synthetically transmit focused images, the multiline signals used to form image scanlines are analyzed for speed of sound variation, and a map 60 of this variation is generated. In a preferred implementation, the phase discrepancy of the received multilines caused by speed of sound variation in the medium is estimated in the angular spectrum domain for the receive angular spectrum. Once the phase is estimated for all locations in an image, the differential phase between two points at the same lateral location, but different depth, is computed. This differential phase is proportional to the local speed of sound between the two points. A color-coded two- or three-dimensional map 60 is produced from these speed of sound estimates and presented to the user.

A multiple aperture ultrasound imaging system may be configured to store raw, un-beamformed echo data. Stored echo data may be retrieved and re-beamformed using modified parameters in order to enhance the image or to reveal information that was not visible or not discernible in an original image. Raw echo data may also be transmitted over a network and beamformed by a remote device that is not physically proximate to the probe performing imaging. Such systems may allow physicians or other practitioners to manipulate echo data as though they were imaging the patient directly, even without the patient being present. Many unique diagnostic opportunities are made possible by such systems and methods.