Concave ultrasound transducers and 3D arrays

A method of ultrasound imaging, comprising:

• transmitting ultrasound energy as an unfocused ultrasound ping in a scan plane towards a scatterer in the scan plane with a transmit aperture comprising exactly one transducer element on an ultrasound transducer array aligned with the scan plane and having a concave curvature about at least one axis;
• receiving ultrasound echoes from the scatterer in the scan plane with a first receive aperture comprising a first receiver group of transducer elements on the ultrasound transducer array;
• coherently combining echoes received by the elements of the first receive aperture;
• adjusting a size of the first receiver group of transducer elements of the first receive aperture so that coherently combining echoes received by the elements of the first receive aperture is performed without phase cancellation;
• and
• forming a first ultrasound image with the coherently combined ultrasound echoes received by the first receive aperture;
• receiving ultrasound echoes from the scatterer in the scan plane with a second receive aperture comprising a second receiver group of transducer elements on the ultrasound transducer array;
• coherently combining echoes received by the elements of the second receive aperture;
• adjusting a size of the second receiver group of transducer elements of the second receive aperture so that coherently combining echoes received by the elements of the second receive aperture is performed without phase cancellation;
• and
• forming a second ultrasound image with the coherently combined ultrasound echoes received by the first and second receive apertures;
• and
• incoherently combining the first ultrasound image and the second ultrasound image.

An ultrasound imaging system, comprising:

• an ultrasound transducer array arranged to transmit and receive ultrasound energy in a first scan plane that extends into a region of interest to be imaged;
• a first transmit aperture comprising a first transmitter group of exactly one element in the ultrasound transducer array aligned with the first scan plane and configured to insonify a scatterer in the first scan plane with ultrasound energy unfocused in the scan plane;
• a first receive aperture comprising a first group of elements in the ultrasound transducer array configured to receive ultrasound echoes from the scatterer in the first scan plane, the first receive aperture being located apart from the first transmit aperture and aligned with the first scan plane;
• a second receive aperture comprising a first group of elements in the ultrasound transducer array configured to receive ultrasound echoes from the scatterer in the first scan plane and aligned with the first scan plane, the second receive aperture being located apart from the first transmit aperture and the first receive aperture;
• and
• a control system in electronic communication with the ultrasound transducer array, the control system configured to change a total aperture size of the system by switching from receiving echoes with the first receive aperture to receiving echoes with the second receive aperture, the control system further configured to combine echoes received by the elements of the first receive aperture coherently without phase cancellation to form a first image and to combine echoes received by the elements of the second receive aperture coherently without phase cancellation to form a second image, the control system also configured to form an ultrasound image of the region of interest in the scan plane by incoherently combining the first image with the second image.