System and method for mapping and quantifying in-vivo blood flow stasis
Described here are systems and methods for producing an image that depicts blood flow stasis using magnetic resonance imaging (MRI), Doppler echocardiography, or other medical instruments for measuring flow velocities in a human body. A time series of three-dimensional (3D) image volumes is provided, where this time series of 3D image volumes contains flow velocity information at voxel locations in a 3D volume in a subject. One or more regions-of-interest are then segmented from the 3D image volumes. For each voxel in the regions-of-interest, velocity magnitudes are calculated. Using the velocity magnitudes, a flow stasis volume is produced by computing a relative stasis value for each voxel location in the corresponding region-of-interest. This flow stasis volume can be provided as a 3D flow stasis image, or a flow stasis map can be produced by projecting the flow stasis volume onto a two-dimensional (2D) plane.
1. A method for producing an image that depicts blood flow stasis using a medical imaging system, the steps of the method comprising:
(a) providing a time series of images acquired with the medical imaging system, the time series of images containing flow velocity information at voxel locations in a three-dimensional volume;
(b) segmenting at least one region-of-interest from each image in the time series of images;
(c) calculating a velocity magnitude for each voxel in each region-of-interest;
(d) producing a flow stasis volume by computing a relative stasis value for each voxel location in each region-of-interest by determining, at a given voxel location, a number of time frames in the time series of images having a velocity magnitude below a user-selected threshold value and normalizing the determined number of time frames at the given voxel location by a total number of time frames in the times series of images; and
(e) generating an image that depicts blood flow stasis from the produced flow stasis volume.
2. The method as recited in claim 1 , wherein step (e) includes providing the produced flow stasis volume as a three-dimensional image that depicts blood flow stasis.
3. The method as recited in claim 1 , wherein step (e) includes producing a flow stasis map by projecting the flow stasis volume onto a two-dimensional (2D) plane, and providing the flow stasis map as the image that depicts blood flow stasis.
4. The method as recited in claim 1 , wherein the time series of images provided in step (a) is a time series of three-dimensional (3D) image volumes.
5. The method as recited in claim 1 , wherein the time series of images provided in step (a) is a time series of two-dimensional (2D) image slices.
6. The method as recited in claim 1 , wherein the medical imaging system is a magnetic resonance imaging (MRI) system.
7. The method as recited in claim 1 , wherein the medical imaging system is an ultrasound system.
8. The method as recited in claim 1 , wherein the user-selected threshold value is in a range of about 0.02 to 0.2 meters per second.
9. The method as recited in claim 1 , wherein the user-selected threshold value is equal to or greater than about 0.04 meters per second.