A method of orienting a tubular structure in a digital image is provided, wherein the image comprises a plurality of intensities corresponding to a domain of points in a D-dimensional space. The method includes selecting a point in the domain of the image, computing, in a neighborhood of the selected point, a gradient of the image, computing an elementary structure tensor at the selected point, determining a structure tensor for the selected point, and finding the eigenvalues of the structure tensors. The eigenvector corresponding to the smallest eigenvalue is aligned with the tubular structure. A cartwheel projection can be calculated about an axis defined by the eigenvector that is aligned with the tubular structure.