A three-dimensional morphological vessel model (20) can be obtained by assigning diameters (14,15) along the vessel derived from a two-dimensional morphological projection (10) at locations in the three-dimensional model defined by the temporal locations (21,22) of a trackable instrument (5). An apparatus (7), a system (1) and a method (100) for use of the system (1) in characterizing the vessel of a living being (2) by rendering a three-5 dimensional morphological vessel model (20) are presented.
