A computer-implemented method of determining non-calcified plaque from a non-contrast Computed Tomography (CT) image of a coronary region of a subject, the method comprising:
- accessing, by a computer system, a non-contrast CT image of a coronary region of a subject;
- identifying, by the computer system, epicardial fat on the non-contrast CT image;
- segmenting, by the computer system, arteries on the non-contrast CT image using the identified epicardial fat as outer boundaries of the arteries;
- identifying, by the computer system, a first set of pixels within the arteries on the non-contrast CT image, the first set of pixels comprising a Hounsfield unit radiodensity value below a predetermined radiodensity threshold;
- classifying, by the computer system, the first set of pixels as a first subset of non-calcified plaque;
- identifying, by the computer system, a second set of pixels within the arteries on the non-contrast CT image, the second set of pixels comprising a Hounsfield unit radiodensity value within a predetermined radiodensity range;
- determining, by the computer system, a heterogeneity index of the second set of pixels and identifying a subset of the second set of pixels comprising a heterogeneity index above a predetermined heterogeneity index threshold, wherein the heterogeneity index of the second set of pixels is determined by generating spatial mapping of Hounsfield unit radiodensity values of the second set of pixels;
- classifying, by the computer system, the subset of the second set of pixels as a second subset of non-calcified plaque;
- and
- determining, by the computer system, non-calcified plaque from the non-contrast CT image by combining the first subset of non-calcified plaque and the second subset of non-calcified plaque,
- wherein the computer system comprises a computer processor and an electronic storage medium.