1. A method for improving visibility and supporting automatic detection and tracking of interventional tools which are to be applied in the scope of minimally invasive X-ray guided interventions, said method comprising the steps of a processor calculating (S 6 ) discrepancy maps graphically illustrating differences between 2D projected image data of a preoperatively acquired 3D voxel volume showing one or more of an anatomical structure or region of interest, pathological abnormalities, pacemakers and other medical implants in a tissue of a patient's body to be examined or in a blood vessel segment of said patient's vascular system and intraoperatively recorded 2D fluoroscopic images showing the one or more of an anatomical structure or region of interest, pathological abnormalities, pacemakers and other medical implants as well as interventional tools which have been introduced into the interior of said patient's body, wherein said 2D fluoroscopic images have been co-registered (S 4 ) with the 2D projected image data, and the processor providing the discrepancy maps as an input to a detection filter to automatically reduce (S 8 a ) a region to which the detection filter is applied; the detection filter using the discrepancy maps as probability maps for the location of the interventional tools by weighing mismatching regions of the discrepany maps as more likely to contain interventional tools.