Image analysis
Provided herein is technology relating to analysis of images and particularly, but not exclusively, to methods and systems for determining the area and/or volume of a region of interest using optical coherence tomography data. Some embodiments provide for determining the area and/or volume of a lesion in retinal tissue using three-dimensional optical coherence tomography data and a two-dimensional optical coherence tomography fundus image.
1. A system for determining the volume of a region of interest of a biological tissue, the system comprising:
a) an OCT apparatus; and
b) software to calculate an area and/or volume of the region of interest V by implementing the following steps in response to a user of the system:
i) acquiring three-dimensional OCT data comprising at least a first segment and a second segment comprising a tissue abnormality;
ii) acquiring two-dimensional image data comprising the tissue abnormality, wherein the tissue abnormality in the three-dimensional OCT data corresponds to the tissue abnormality in the two-dimensional data;
iii) drawing a boundary around the tissue abnormality in the two-dimensional image data, the boundary enclosing an area A, wherein the two-dimensional image data and three-dimensional OCT data are registered via a computer processor so that the tissue abnormality is identified in the three-dimensional OCT data by the boundary drawn on the two-dimensional image and displayed on a computer screen;
iv) calculating a volume v within the boundary and between the first segment and the second segment;
v) calculating an average thickness t between the first segment and the second segment along the boundary; and
vi) calculating the volume of the region of interest V=v−(t×A).
2. The system of claim 1 further comprising a component configured to display three-dimensional OCT data and two-dimensional image data to a user.
3. The system of claim 2 wherein the two-dimensional image data is OCT fundus data, a two-dimensional image produced by integrating three-dimensional OCT data, a cross-sectional slice of three-dimensional OCT data, or a photograph.
4. The system of claim 1 further comprising a component configured to accept input from a user to provide the boundary around the region of interest or a plurality of points indicating the boundary around the region of interest in the two-dimensional image data.
5. The system of claim 1 further comprising a component to output the area and/or the volume of the region of interest.