Apparatuses and methods for navigation in and local segmentation extension of anatomical treelike structures

A method comprising:

• receiving 3D image data;
• segmenting an initial treelike structure in the 3D image data to create an initial segmentation;
• creating a skeletonization of the initial segmentation;
• mask-labeling voxels in the initial segmentation according to the skeletonization;
• defining a target point in the initial segmentation;
• extracting a region of interest based on the target point to create a sub-image;
• smoothing the sub-image;
• enhancing contrast in the sub-image;
• detecting highly tubular voxels in the sub-image;
• performing a spillage-constrained region growing using the highly tubular voxels as seed points;
• extracting connected components from the region growing results;
• creating a skeletonization of the extracted components;
• mask-labeling voxels in the extracted components according to the skeletonization;
• pruning the extracted components to discard components not likely to be connected to the initial treelike structure and keep only candidate components likely to be a valid sub-tree of the initial treelike structure;
• and
• connecting the candidate components to the initial treelike structure.

The method of claim 19, wherein pruning comprises:

• discarding components based on whether they have genus zero and are relatively convex, including determining whether a ratio of a volume of the extracted component before morphological closing to a volume of the extracted component after morphological closing is greater than a threshold;
• discarding or modifying components based on the components curving more than a threshold amount, including determining whether a dot product of a direction of the extracted component and a direction of a segment of the extracted component is below a threshold;
• discarding components based on a shape analysis of the shape of the extracted component, including comparing shape analysis metrics including at least one of a minor axis length, an elongation, and an eccentricity of the extracted component to target metrics;
• and
• discarding components based on a cylindrical score of the components, including determining a circle equivalent diameter of the extracted component.