VATRKVisionX V4
NAME
vatrk − tracks the aorta in a ct image
SYNOPSISvatrk if=<infile> of=<outfile> of2=<outfile2> x1=<> y1=<> z1=<> h=<> in=<> -u -d -g -t
DESCRIPTIONvatrk vatrk tracks the aorta upwards (-u) or downwards (-d) by performing iterative cylinder fitting. The initial seed point (x1,y1,z1) and the direction flag determine where and in what direction the tracking starts. h= is the cylinder length. in= is the precentage a cylinder progresses in each iteration. Descending tracking uses the following steps and constraints:
(1) (x1,y1,z1) is the center of the estimated aorta seed point and initial direction is going straight down. h= is 20 mm by default and in= is 0.2 by default (20%*h).
(2) Generate candidate cylinders for first iteration with different radii and orientations. For first iteration the search space for radius is from 8mm to 30mm and the search space for orientation is azimuthal alpha = PI/4 for ascending tracking and (7/32)*PI for descending tracking; polar angle beta = 2*PI.
(3) Obtain the best cylinder, i.e. highest score (1*unlabeled+(-30)*labeled). Check whether the best cylinder has a. a score greater than 0; b. reaches the limit of image; c. a radius within the range of 0.5-2 times the radius of any previous cylinder (not applicable for first iteration).
(4) If all 3 criteria are met in step (3), proceeds to next iteration, otherwise terminate tracking. For next iteration, the new reference cylinder follows the direction of the previous cylinder with a 20% (in=) increment. Based on the reference cylinder, the search space for candidate cylinders is: radius 0.8-1.2 times radius of previous best cylinder and same alpha beta angle as before.
(5) Perform (3) and (4) repeatedly until tracking is terminated. Return a vector containing: center point locations of all best cylinders and their respective estimated radius; endpoint of first and last cylinder.
Ascending tracking follows the same steps and uses mostly the same parameters. The only differences are: reverse the initial tracking direction to straight up; in step (4) the radius search space is 0.5 to 1.5 of previous best cylinder.
Input file if= is a VXB image. Output file of= is a VXB image. Output file of2= is a generic float vector file (VX_GFLOAT). Each row of of2= contains a 3D point with an estimated radius (x,y,z,r).
OPTIONS|
if= |
input chest map (VXB) | ||
|
of= |
output image (VXB), visualization for the aorta tracking | ||
|
of2= |
output vector file, mid-points of all cylinders | ||
|
x1,y1,z1= |
x,y,z coordinates of the seed point | ||
|
h= |
cylinder height (mm space) | ||
|
in= |
cylinder progress length (percentage of h) | ||
|
-u |
upward tracking flag | ||
|
-d |
downward tracking flag | ||
|
-g |
downward tracking gravity flag | ||
|
-t |
upward tracking flag (using smaller tracking angle alpha=3*PI/16) |
vaorta(1),vpcyltrk(1),vairseg(1)
AUTHORJ. Lee, J. Wala, Y. Xie