Embodiments described provide an ultrasound method, and an ultrasound apparatus and computer program product operable to perform that method. In some embodiments, the method allows for provision of a multi-transducer ultrasound imaging system by providing a robust method to accurately localize the transducers in the system in order to beamform a final image. The method and apparatus described allow for improvements in imaging quality in terms of resolution, depth penetration, contrast and signal to noise ratio (SNR).

Provided is an ultrasound diagnosis apparatus including a probe configured to transmit a plurality of plane waves at a plurality of steering angles and a controller configured to determine the plurality of plane waves so that a grating lobe of a synthetic transmit focusing beam pattern using the plurality of plane waves is located outside a region of interest.

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.

Disclosed herein is a method of ultrasound imaging of an object using an ultrasound transducer which comprises an array of transducer elements capable of converting sound signals into electrical signals and vice versa, comprising the following steps: A) transmitting an ultrasound beam from said ultrasound transducer into the object, by activating a first subset of said transducer elements, B) detecting reflected signals in a time resolved manner by means of a second subset of said transducer elements, wherein timing information of a detected signal is associated with information regarding the depth where the detected signal was reflected within the object subjected to imaging, and wherein the reflected signals associated with said second subset of transducer elements resemble a set of two-dimensional ultrasound data, of which one dimension resembles the various transducer elements of said second subset and the other dimension resembles depth information, C) converting said two-dimensional ultrasound data into a scan object using a receive beamforming procedure which accounts for differences in distance of individual transducer elements from a given site of sound reflection within the object, repeating steps A) to C) for different choices regarding at least one of said first and second subsets and the timing of the activation of transducer elements within said first subset, thereby obtaining a plurality of scan objects, and a step of constructing a visual image from said plurality of scan objects, wherein said receive beamforming procedure employs a machine learning based receive beamforming model for mapping said two-dimensional ultrasound data to said scan object.

Shear wave propagation is used to estimate the speed of sound in a patient. An ultrasound scanner detects a time of occurrence of a shear wave at each of multiple locations. The difference in time of occurrence, given tissue stiffness or shear velocity, is used to estimate the speed of sound for the specific tissue of the patient.

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.

An ultrasound imaging system includes an array of acoustic elements configured to transmit ultrasound energy at a first transmit speed and receive echoes associated with the ultrasound energy transmitted at the first transmit speed. The system further includes a processor circuit in communication with the array of acoustic elements. The processor is configured to generate a plurality of multilines based on the received echoes, determine a second transmit speed, determine a set of transmit focus delays based on the second transmit speed, adjust the plurality of multilines using the set of transmit focus delays, generate an image based on the adjusted plurality of multilines, and output the generated image to a display in communication with the processor circuit.

For ultrasound imaging with an ultrasound scanner, fat fraction of the tissue is measured. The fat fraction may be measured without access to channel data, such as from beamformed data. The speed of sound varies with the fat fraction of tissue, so the fat fraction is used to set the speed of sound in beamforming. Imaging the tissue using the fat fraction-based optimization for speed of sound may provide better images than imaging with an assumed speed.

An ultrasound diagnostic apparatus includes an ultrasound image producer which produces an ultrasound image from reception data based on a predetermined set sound speed, a reception data image producer which produces a reception data image representing a luminance image of an ultrasonic echo wavefront from the reception data corresponding to a predetermined range on at least one scan line in the ultrasound image, a sound speed determination unit configured to determine an optimum sound speed based on ultrasound images respectively produced by the ultrasound image producer while changing the predetermined set sound speed, and a controller which makes an ultrasound image for diagnosis produced by the ultrasound image producer and the reception data image produced by the reception data image producer be displayed simultaneously on a display unit based on the optimum sound speed determined by the sound speed determination unit.

Various approaches for calibrating the geometry of an ultrasound transducer having multiple transducer elements include providing an acoustic reflector spanning an area traversing by multiple beam paths of ultrasound waves transmitted from all (or at least some) transducer elements to a focal zone; causing the transducer elements to transmit the ultrasound waves to the focal zone; measuring reflections of the ultrasound waves off the acoustic reflector; and based at least in part on the measured reflections, determining optimal geometric parameters associated with the transducer elements.