Image acquisition of deployment of endo-vascular prosthesis (stent) into an artery uses X ray radiography with zoom and enlargement functions

摘要

The image is produced with a global enlargement equal to (fs / fFSC) * (ESD * ( pi / 180)). f-s is the inverse fundamental frequency of the stents spatial period in line pairs per millimeter, fFSC is a spatial frequency corresponding to maximum sensitivity to contrast of the human eye in cycles by degree, and ESD is the distance in millimeters between means on which images are displayed and an observer viewing them. The stent has a trellis like structure and its image is acquired by a radiography system having an X ray source (4) and sensors (7). TO display the images with such an enlargement a digital zoom is applied to them equal to: Mz = ( pi * fs * ESD * FOV * SOD) / (180 * fFSC * FOD * SID). FOV designates the image projection field on the sensors (7), SOD is the distance between source (4) and stent (1), FOD designates the image display field on the display (8) and SID the distance between source and sensors.