The invention relates to a system and a method for guiding an intravascular ultrasound catheter device comprising an ultrasound probe to a potential lesion in a vascular tree (31). In the system, position information of the probe are provided for displaying to a user and/or for an automated processing of the position information. An evaluation unit is configured to receive a diagnostic image of the vascular tree, to determine values of at least one vessel parameter for a plurality of locations in the vascular tree, and to identify at least one location associated with an abnormal value of the at least one vessel parameter. Further, a mapping unit is configured to provide a visual indication (32) of the at least one location in the visualization of the vascular tree and/or to provide information about the at least one location for use in the automated processing of the position information.
