Analysis and visualization of OCT angiography data

Patent metadata

Field	Value
Publication number	US-9357916-B2
Application number	US-201313781375-A
Country	US
Kind code	B2
Filing date	Feb 28, 2013
Priority date	May 10, 2012
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

Methods for analyzing and visualizing OCT angiography data are presented. In one embodiment, an automated method for identifying the foveal avascular zone in a two dimensional en face image generated from motion contrast data is presented. Several 3D visualization techniques are presented including one in which a particular vessel is selected in a motion contrast image and all connected vessels are highlighted. A further embodiment includes a stereoscopic visualization method. In addition, a variety of metrics for characterizing OCT angiography image data are described.

First claim

What is claimed is:

1. An automated method for identifying areas of interest in optical coherence tomography (OCT) image data of an eye, said method comprising:
collecting OCT image data over a plurality of transverse locations of the eye of a patient, wherein at least some of the OCT measurements are obtained at approximately the same transverse locations separated in time by a predetermined interval;
processing the data to determine changes in the OCT measurements obtained at approximately the same transverse locations, said changes being associated with blood flow that occurs during the predetermined interval;
generating a two-dimensional en face vasculature image from the processed data;
analyzing the intensity content of the en face vasculature image to identify the size and shape of a particular area;
displaying or storing the identified area, wherein the analyzing step includes:
generating a histogram that includes the frequency distribution of the intensity values of pixels in the image data;
estimating an intensity value between two peaks in the histogram that corresponds to a transition zone around the particular area;
generating isophotes within the en face image based on the estimated intensity value; and
evaluating the isophotes to identify the size and shape of the particular area.

2. A method as recited in claim 1 , wherein the identified area is the foveal avascular zone (FAZ).

3. A method as recited in claim 1 , wherein the identified area is a region of retinal ischemia.

4. A method as recited in claim 1 , further comprising identifying layers in the retina and using these layers as boundaries in generating the en face vasculature image.

5. A method as recited in claim 1 , wherein the analysis of the en face image involves generating an intensity histogram from the en face image, identifying the intensities corresponding to peaks in the histogram, determining the transition between the identified area and the rest of the vasculature as a combination of these intensities, and locating, in the en face vasculature image, regions corresponding to these intensity values.

6. A method as recited in claim 1 , further comprising dividing the en face vasculature image into sectors and using intensity to determine a proportion of a vessel in a sector in relation to the background.

7. A method as recited in claim 1 , further comprising generating a three dimensional representation of the retinal vasculature.

8. A method as recited in claim 1 , further comprising using an additional property of the en face vasculature image in addition to intensity to identify the particular area.

9. A method for visualizing optical coherence tomography (OCT) image data of the eye, said method comprising:
collecting OCT image data over a plurality of transverse locations of the eye of a patient wherein at least some of the OCT measurements are obtained at approximately the same transverse locations separated in time by a predetermined interval;
processing the data to determine changes in the OCT measurements obtained at approximately the same transverse locations, said changes being associated with blood flow during the predetermined interval;
generating a 3D visualization of the of the processed data including blood vessels;
receiving input from an operater selecting a particular blood vessel from said 3D visualization and then highlighting the operator selected blood vessel and only those other blood vessels that are directly connected to the selected vessel down to the capillary level and that are within the collected OCT image data.

10. A method as recited in claim 9 , wherein the 3D visualization is in the form of a movie and wherein connecting vessels are highlighted propagating from the operator selected vessel down to the capillary level.

11. A method as recited in claim 10 , wherein the speed of highlighting propagation is determined by the vessel diameter.

12. A method as recited in claim 1 , wherein the identified area is a region of the retina that is devoid of capillaries.

13. A method as recited in claim 1 , wherein the identified area is a region of non-perfusion.

Assignees

• Zeiss Carl Meditec Inc

Inventors

• Srivastava Siddharth
• Sharma Utkarsh
• Durbin Mary K
• Schmoll Tilman

Classifications

• G06T12/00

  Tomographic reconstruction from projections · CPC title

• G06T2207/30041

  Eye; Retina; Ophthalmic · CPC title

• G06T19/00

  Manipulating three-dimensional [3D] models or images for computer graphics · CPC title

• G06T2210/41

  Medical · CPC title

• A61B3/102 Primary

  for optical coherence tomography [OCT] · CPC title