ULTRASOUND DIAGNOSTIC APPARATUS AND ULTRASOUND IMAGING METHOD
An ultrasound diagnostic apparatus according to an embodiment includes an ultrasound probe and processing circuitry. The ultrasound probe sequentially executes sets of ultrasound transmission respectively along a plurality of scan lines, the sets each being composed only of transmission of first ultrasound having a first phase and transmission of second ultrasound having a second phase that is substantially 90 degrees different from the first phase. With respect to a first echo signal and a second echo signal that have been obtained via the ultrasound probe and correspond to the first ultrasound and the second ultrasound, respectively, the processing circuitry generates a subtraction signal by subtracting the second echo signal from the first echo signal. The processing circuitry generates an ultrasound image based on the subtraction signals generated for the scan lines.
1 . An ultrasound diagnostic apparatus comprising:
an ultrasound probe configured to sequentially execute sets of ultrasound transmission respectively along a plurality of scan lines, the sets each being composed only of transmission of first ultrasound and transmission of second ultrasound, the first ultrasound having a first phase, the second ultrasound having a second phase that is substantially 90 degrees different from the first phase; and
processing circuitry configured to
with respect to a first echo signal and a second echo signal that have been acquired via the ultrasound probe and correspond to the first ultrasound and the second ultrasound, respectively, generate a subtraction signal by subtracting the second echo signal from the first echo signal, and
generate an ultrasound image based on the subtraction signals generated for the scan lines.
2 . The ultrasound diagnostic apparatus according to claim 1 , further comprising a filter configured to apply a high-pass filter or a band-pass filter to the first echo signals and the second echo signals, or to the subtraction signals.
3 . The ultrasound diagnostic apparatus according to claim 2 , wherein
the filter applies a filter that removes fundamental-wave components contained in the first echo signals and the second echo signals or in the subtraction signals to extract at least second-order harmonic components, and
the processing circuitry generates the ultrasound image using the extracted second-order harmonic components.
4 . The ultrasound diagnostic apparatus according to claim 1 , further comprising a switching circuit configured to select, from among a plurality of alternative units including transmitter circuitry and receiver circuitry, a unit to which each of the transducer elements included in the ultrasound probe is connected.
5 . The ultrasound diagnostic apparatus according to claim 1 , wherein the ultrasound probe is a 2D array probe having a plurality of transducer elements arrayed in a matrix.
6 . The ultrasound diagnostic apparatus according to claim 5 ,
wherein the 2D array probe comprises:
a plurality of sub-arrays each composed of a plurality of transducer elements;
a main array composed of the sub-arrays; and
a delay adding circuit configured to execute processing of adding together delays of echo signals with respect to each of the sub-arrays.
7 . An ultrasound imaging method comprising:
causing an ultrasound probe to sequentially execute sets of ultrasound transmission respectively along a plurality of scan lines, the sets each being composed only of transmission of first ultrasound and transmission of second ultrasound, the first ultrasound having a first phase, the second ultrasound having a second phase that is substantially 90 degrees different from the first phase;
with respect to a first echo signal and a second echo signal that have been acquired via the ultrasound probe and correspond to the first ultrasound and the second ultrasound, respectively, generating a subtraction signal by subtracting the second echo signal from the first echo signal; and
generating an ultrasound image based on the subtraction signals generated for the scan lines.