1. The method for generating an image, comprising: obtaining 3D rotational angiography (3DRA) data set(s) for an anatomical region containing an anatomical structure; segmenting the anatomical structure from the 3DRA data set(s); obtaining an independent 3D diagnostic data set(s) for the anatomical region, the independent 3D diagnostic data set being different from the 3DRA data set; registering the 3DRA and the 3D diagnostic data set(s) in the anatomical region; selecting a slab portion of the 3D diagnostic data set(s), the slab portion being smaller than the anatomical region; generating a silhouette rendering of a portion of the anatomical structures segmented from the 3DRA data sets(s) which is disposed in the slab portion, the silhouette rendering depicting only edges of the segmented anatomical structure, the edges being distinguishable from the slab portion when the silhouette rendering is combined with the slab portion; combining a portion of the segmented 3DRA data set(s) that is disposed outside of the slab, the silhouette rendering of the portion of the anatomical structures segmented from the 3DRA data set(s) that is disposed in the slab portion, and the slab portion of the 3D diagnostic data set(s); and generating an image that combines: the slab portion of the 3D diagnostic data set(s), a surface or volume rendering of the anatomical structure segmented from the 3DRA data set(s) disposed outside of the slab portion, and the silhouette rendering of the portion of anatomical structure in the slab portion.