1. A method of detecting at least one feature associated with a blood vessel in at least one image of at least one blood vessel using a matched filter adapted to respond to the at least one feature, the method comprising: applying a scale detection filter to selected voxels in the at least one image to determine a scale for the matched filter at each of the selected voxels; determining an orientation for the matched filter at each of the selected voxels, wherein determining the orientation is assisted by using the scale determined at each of the selected voxels; applying the matched filter at each of the selected voxels at the scale and the orientation determined at each of the selected voxels to obtain a filter response at each of the selected voxels; and analyzing the filter response at each of the selected voxels to determine if the respective voxel corresponds to the at least one feature.