Ultrasonic diagnostic apparatus, medical image processing apparatus, and medical image processing method
According to one embodiment, an ultrasonic diagnostic apparatus includes an ultrasonic probe, transmission unit transmitting a first ultrasonic wave for generating a shear wave in an object to a first region and a second ultrasonic wave to a second region, reception unit generating a reception signal based on the second ultrasonic wave, displacement amount calculation unit calculating a displacement amount of a tissue accompanying propagation of the shear wave to the second region by using the reception signal, arrival time decision unit deciding an arrival time when the shear wave has arrived at each position in the second region, based on a temporal change in the displacement amount concerning the each position, and image generation unit generating based on the arrival time and predetermined pixel values corresponding to the arrival times, a shear wave arrival time image with the pixel values being assigned corresponding to the arrival times.
1. An ultrasonic diagnostic apparatus comprising:
an ultrasonic probe configured to perform an ultrasound transmission for generating a shear wave, and perform ultrasound scans for a region where the shear wave propagates; and
processing circuitry configured to:
calculate displacement amounts of each position in the region over time based on reception signals generated by the ultrasound scans;
determine an arrival time when the shear wave has arrived, for each position in the region, based on a temporal change in the displacement amounts of the position, the arrival time of the position being relative to a reference time that indicates when the shear wave propagating in the region has arrived at a point corresponding to the position and located along a reference line that is designated within the region, the reference time varying depending on when the shear wave arrives at points located along the reference line; and
generate and control a display to display a shear wave arrival time image formed by pixels, a pixel value at each of the pixels representing the arrival time at each of positions in the region and being assigned a hue corresponding to the arrival time.
2. The ultrasonic diagnostic apparatus of claim 1 , wherein the processing circuitry is further configured to determine the arrival time based on a maximum displacement amount of the displacement amounts.
3. The ultrasonic diagnostic apparatus of claim 1 , wherein the processing circuitry is further configured to determine the arrival time based on a maximum displacement amount of maximal values of temporal changes in the displacement amount.
4. The ultrasonic diagnostic apparatus of claim 1 , wherein the processing circuitry is further configured to determine the arrival time based on a maximum time change of temporal changes in the displacement amount.
5. The ultrasonic diagnostic apparatus of claim 1 , wherein the processing circuitry is further configured to calculate the displacement amounts along a direction away from the ultrasonic probe as the displacement amount.
6. The ultrasonic diagnostic apparatus of claim 1 , further comprising
a peripheral device configured to input a designated region designated by an operator, wherein the processing circuitry is configured to
determine a corrected arrival time at the each position with reference to the reference time for the designated region, and
generate a corrected shear wave arrival time image by correcting a pixel value in the shear wave arrival time image, based on the corrected arrival time and the pixel value.
7. The ultrasonic diagnostic apparatus of claim 1 , wherein the processing circuitry is further configured to:
calculate a propagation velocity of a shear wave at the each position by using the arrival time at the each position; and
generate, based on the calculated propagation velocities and pixel values set in advance in accordance with the propagation velocities, a shear wave propagation velocity image with the pixel values being assigned in accordance with the propagation velocities at the respective positions.
8. The ultrasonic diagnostic apparatus of claim 1 , further comprising:
a peripheral device configured to input a designated region designated by an operator,
wherein the processing circuitry is further configured to calculate a propagation velocity of a shear wave propagating in the designated region by using the arrival time at each position in the designated region.
9. The ultrasonic diagnostic apparatus of claim 1 , further comprising:
a peripheral device configured to input a designated region designated by an operator,
wherein the processing circuitry is further configured to calculate an elastic modulus in the designated region by using a propagation velocity of the shear wave propagating in the designated region.
10. A medical image processing apparatus comprising:
a storage configured to store a reception signal; and
processing circuitry configured to:
calculate tissue displacement amounts of each position in a region over time based on reception signals generated by an ultrasound scans;
determine an arrival time when a shear wave has arrived, for each position in the region, based on a temporal change in the tissue displacement amounts of the position, the arrival time of the position being relative to a reference time that indicates when the shear wave propagating in the region has arrived at a point corresponding to the position and located along a reference line that is designated within the region, the reference time varying depending on when the shear wave arrives at points located along the reference line; and
generate and control a display to display a shear wave arrival time image formed by pixels, a pixel value at each of the pixels representing the arrival time at each of positions in the region.
11. A medical image processing method comprising:
storing a reception signal;
calculating tissue displacement amounts of each position in a region over time based on reception signals generated by an ultrasound scans;
determining an arrival time when a shear wave has arrived, for each position, based on a temporal change in the tissue displacement amounts of the position, the arrival time of the position being relative to a reference time that indicates when the shear wave propagating in the region has arrived at a point corresponding to the position and located along a reference line that is designated within the region, the reference time varying depending on when the shear wave arrives at points located along the reference line; and
generating and controlling a display to display a shear wave arrival time image formed by pixels, a pixel value at each of the pixels representing the arrival time at each of positions in the region and being assigned a hue corresponding to the arrival time.
12. An ultrasonic diagnostic apparatus comprising:
an ultrasonic probe configured to perform an ultrasound transmission for generating a shear wave, and perform ultrasound scans for a region where the shear wave propagates; and
processing circuitry configured to:
calculate displacement amounts of each position of the region over time based on reception signals generated by the ultrasound scans;
obtain a body movement displacement amount which is a displacement amount based on a body movement of an object to be scanned, and subtract the body movement displacement amount from the displacement amounts;
determine an arrival time when the shear wave has arrived, for each position in the region, based on a temporal change in the subtraction result displacement amounts of the position, the arrival time of the position being relative to a reference time that indicates when the shear wave propagating in the region has arrived at a point corresponding to the position and located along a reference line that is designated within the region, the reference time varying depending on when the shear wave arrives at points located along the reference line; and
generate and control a display to display a shear wave arrival time image formed by pixels, a pixel value at each of the pixels representing the arrival time at each of positions in the region and being assigned a hue corresponding to the arrival time.