System and method for flow or velocity quantification using contrast-enhanced x-ray data

Patent metadata

Field	Value
Publication number	US-2024260916-A1
Application number	US-202318163475-A
Country	US
Kind code	A1
Filing date	Feb 2, 2023
Priority date	Feb 2, 2023
Publication date	Aug 8, 2024
Grant date	—

Abstract

A system and method are provided that includes acquiring or accessing x-ray data of a subject experiencing a delivery of a contrast agent to the vessel of the subject and generating time-attenuation curves for the vessel using the x-ray data. The method also includes identifying a plurality of points within the vessel and extending along a lumen of the vessel and sampling the time-attenuation curves at the plurality of points to generate a time-attenuation map. The method further includes performing a Fourier transform on the time-attenuation map to generate a spatio-temporal map of spatial frequency versus temporal frequency and identifying a peak frequency in the spatio-temporal map corresponding to flow or velocity in the vessel. The method then includes quantifying the flow or velocity within the vessel of the subject using the peak frequency and generating a report including quantified flow or velocity through the vessel.

First claim

1 . A system for generating images quantifying flow or velocity within a vessel of a subject, the system comprising:
an x-ray imaging system configured to acquire x-ray data from the subject while a contrast agent is delivered to the vessel of the subject; a computer system configured to:
generate time-attenuation curves for the vessel using the x-ray data;
identify a plurality of points within the vessel and extending along a lumen of the vessel;
sample the time-attenuation curves at the plurality of points to generate a time-attenuation map;
perform a domain transform on the time-attenuation map to generate a spatio-temporal map of spatial frequency versus temporal frequency;
identify a peak frequency in the spatio-temporal map corresponding to flow or velocity in the vessel;
quantify the flow or velocity within the vessel of the subject using the peak frequency; and
generate a report indicating quantified flow or velocity through the vessel.

2 . The system of claim 1 , wherein a first axis of the spatio-temporal map corresponds to frequencies in the time domain and a second axis of the spatio-temporal map corresponds to frequencies in the spatial domain.

3 . The system of claim 2 , wherein the peak frequency in the spatio-temporal map corresponding to flow or velocity in the vessel is identified relative to the second axis.

4 . The system of claim 3 , wherein the computer system is further programmed to determine a tangent of an angle between the first axis and a line from an origin of the first axis and the second axis to the peak frequency in the spatio-temporal map corresponding to velocity.

5 . The system of claim 1 , wherein the computer system is further programmed to calculate frequency amplitudes in the spatio-temporal map by taking an absolute value of complex Fourier coefficients.

6 . The system of claim 1 , wherein the computer system is further programmed to subtract mask x-ray data from the x-ray data before generating the time-attenuation curves for the vessel using the x-ray data.

7 . The system of claim 1 , wherein the computer system is further programmed to subtract adjacent contrast enhanced projection data from the x-ray data before generating the time-attenuation curves for the vessel using the x-ray data.

8 . The system of claim 1 , wherein the x-ray data includes at least one of quantitative digital subtraction angiography data or four-dimensional digital subtraction angiography data.

9 . The system of claim 1 , wherein the computer system is further programmed to determine a centerline for the vessel and identify the plurality of points on the centerline.

10 . The system of claim 9 , wherein the plurality of points are uniformly distributed over the centerline.

11 . A method for generating a report quantifying flow or velocity within a vessel of a subject, the method comprising:
acquiring or accessing x-ray data of a subject experiencing a delivery of a contrast agent to the vessel of the subject; generating time-attenuation curves for the vessel using the x-ray data; identifying a plurality of points within the vessel and extending along a lumen of the vessel; sampling the time-attenuation curves at the plurality of points to generate a time-attenuation map; performing a domain transform on the time-attenuation map to generate a spatio-temporal map of spatial frequency versus temporal frequency; identifying a peak frequency in the spatio-temporal map corresponding to flow or velocity in the vessel; quantifying the flow or velocity within the vessel of the subject using the peak frequency; and generating a report including quantified flow or velocity through the vessel.

12 . The method of claim 11 , wherein a first axis of the spatio-temporal map corresponds to frequencies in the time domain and a second axis of the spatio-temporal map corresponds to frequencies in the spatial domain.

13 . The method of claim 12 , wherein the peak frequency in the spatio-temporal map corresponding to flow or velocity in the vessel is identified relative to the second axis.

14 . The method of claim 13 , further comprising determining a tangent of an angle between the first axis and a line from an origin of the first axis and the second axis to the peak frequency in the spatio-temporal map corresponding to velocity.

15 . The method of claim 11 , further comprising calculating frequency amplitudes in the spatio-temporal map by taking an absolute value of complex Fourier coefficients.

16 . The method of claim 11 , further comprising subtracting mask x-ray data from the x-ray data before generating the time-attenuation curves for the vessel using the x-ray data.

17 . The method of claim 11 , further comprising subtracting adjacent contrast enhanced projection data from the x-ray data before generating the time-attenuation curves for the vessel using the x-ray data.

18 . The method of claim 11 , wherein the x-ray data includes at least one of quantitative digital subtraction angiography data or four-dimensional digital subtraction angiography data.

19 . The method of claim 11 , further comprising determining a centerline for the vessel and identify the plurality of points on the centerline.

20 . The method of claim 19 , wherein the plurality of points are uniformly distributed over the centerline.

21 . The method of claim 11 , wherein the quantified flow or velocity through the vessel includes a quantified velocity measure of flow or velocity through the vessel.

22 . The method of claim 11 , wherein the peak frequency in the spatio-temporal map corresponding to flow or velocity in the vessel is a maximum value in a power spectrum representing a fundamental frequency peak.

23 . The method of claim 11 , further comprising subtracting a global mean of the time attenuation map to remove a constant offset or performing a zero padding to decrease the spacing between frequencies.

24 . The method of claim 11 , further comprising determining harmonic frequencies using the spatio-temporal map and using the harmonic frequencies to identify systolic and diastolic flow within the vessel.

Assignees

• Wisconsin Alumni Res Found

Inventors

• Wagner Martin
• Whitehead Joseph
• Speidel Michael
• Laeseke Paul

Classifications

• A61B6/486

  involving generating temporal series of image data · CPC title

• A61B6/52

  Devices using data or image processing specially adapted for radiation diagnosis · CPC title

• A61B6/507

  for determination of haemodynamic parameters, e.g. perfusion CT · CPC title

• A61B6/4441

  the rigid structure being a C-arm or U-arm · CPC title

• G06T7/254

  involving subtraction of images · CPC title