Methods and systems for automated center positioning for radial velocity mapping in vector contrast imaging
A method ( 100 ) for generating a radial velocity map for a target region, comprising: (i) receiving ( 120 ) a series of ultrasound images of the target region; (ii) generating ( 130 ) a grid representing the target region and comprising a plurality of points each representing a possible radial center in the target region; (iii) generating ( 140 ) a radial flux magnitude map for the grid comprising a radial contrast flux for each of the points, comprising the following which are repeated until a radial contrast flux is calculated for each of the points: selecting ( 142 ) one of the points as a radial center; calculating ( 144 ) a radial velocity field for a first region around the selected point; and determining ( 146 ) a radial contrast flux for the first region; and (iv) automatically selecting ( 150 ) a radial center for the series of contrast images.
1 . A method for generating a radial velocity map for a target region, comprising:
receiving a series of contrast images of the target region visualized using contrast-enhanced ultrasound;
generating a grid representing some or all of the target region and comprising a plurality of points each representing a possible radial center in the target region;
generating a radial flux magnitude map for the grid comprising a radial contrast flux for each of the plurality of points, comprising the following steps which are repeated until a radial contrast flux is calculated for each of the plurality of points:
selecting one of plurality of points as a radial center;
calculating, for each of the series of contrast images, a radial velocity field for a first region around the selected point; and
determining, for a single accumulated image generated from some or all of the series of contrast images, a radial contrast flux for the first region; and
automatically selecting, using the generated radial flux magnitude map, a radial center for the series of contrast images, wherein the selected radial center comprises a point of the plurality of points with a maximum radial contrast flux relative to the remainder of the plurality of points.
2 . The method of claim 1 , wherein determining radial contrast flux comprises the steps of:
determining a radial flux volume by summing, for a single accumulated image generated from some or all of the series of contrast images, the calculated radial velocity field over all pixels within the first region; and
dividing the determined radial flux volume by time and by area of the first region.
3 . The method of claim 2 , wherein determining a radial flux volume (RFV) comprises the equation:
RFV
=
∑
(
V
r
·
Δ
S
·
Δ
T
)
where V r =radial velocity field, ΔS=area coverage of one pixel for 2D images or volume coverage of one voxel for 3D images, and ΔT=time interval between two consecutive images in the series of contrast images.
4 . The method of claim 2 , wherein dividing the determined radial flux volume by time and by area of the first region to generate radial contrast flux (Flux) comprises the equation:
Flux
=
RFV
/
T
/
A
where T=ΔT·(N 2 −N 1 ) where N 1 is a starting image in the series of contrast images and N 2 is an ending image in the series of contrast images, and A=area of the first region for 2D images or volume of the first region for 3D images.
5 . The method of claim 1 , wherein the plurality of points are equidistantly spaced within the grid.
6 . The method of claim 1 , wherein the plurality of points comprises fewer than all pixels within the target region.
7 . The method of claim 1 , wherein a density of the plurality of points within the grid is automatically determined.
8 . The method of claim 1 , further comprising the step of providing, via a user interface, the selected radial center and/or the generated radial flux magnitude map.
9 . A computer-readable storage medium embodied in non-transitory memory comprising instructions which, when executed by a computer, cause the computer to carry out the steps of the method of claim 1 .
10 . A system for generating a radial velocity map for a target region, comprising:
a series of contrast images of the target region visualized using contrast-enhanced ultrasound;
a processor configured to: (i) generate a grid representing some or all of the target region and comprising a plurality of points each representing a possible radial center in the target region; (ii) generate a radial flux magnitude map for the grid comprising a radial contrast flux for each of the plurality of points, comprising the following steps which are repeated until a radial contrast flux is calculated for each of the plurality of points: (a) selecting one of plurality of points as a radial center; (b) calculating, for each of the series of contrast images, a radial velocity field for a first region around the selected point; and (c) determining, for a single accumulated image generated from some or all of the series of contrast images, a radial contrast flux for the first region; and (iii) select, using the generated radial flux magnitude map, a radial center for the series of contrast images, wherein the selected radial center comprises a point of the plurality of points with a maximum radial contrast flux relative to the remainder of the plurality of points; and
a user interface configured to provide the selected radial center.
11 . The system of claim 10 , wherein determining radial contrast flux comprises the steps of:
determining a radial flux volume by summing, for a single accumulated image generated from some or all of the series of contrast images, the calculated radial velocity field over all pixels within the first region; and
dividing the determined radial flux volume by time and by area of the first region.
12 . The system of claim 11 , wherein determining a radial flux volume (RFV) comprises the equation:
RFV
=
∑
(
V
r
·
Δ
S
·
Δ
T
)
where V r =radial velocity field, ΔS=area coverage of one pixel for 2D images or volumetric coverage of one voxel for 3D images, and ΔT=time interval between two consecutive images in the series of contrast images.
13 . The system of claim 11 , wherein dividing the determined radial flux volume by time and by area of the first region to generate radial contrast flux (Flux) comprises the equation:
Flux
=
RFV
/
T
/
A
where T=ΔT·(N 2 −N 1 ) where N 1 is a starting image in the series of contrast images and N 2 is an ending image in the series of contrast images, and A=area of the first region for 2D images or volume of the first region for 3D images.
14 . The system of claim 10 , wherein the plurality of points are equidistantly spaced within the grid.
15 . The system of claim 10 , wherein the plurality of points comprises fewer than all pixels within the target region.
16 . The system of claim 10 , wherein the user interface is further configured to provide the generated radial flux magnitude map.