Visualization of stent during coronary angioplasty
Blue arrows: edges of stent; red arrows: balloon edge markers (there will be an overhang of the balloon beyond the markers on either side); yellow arrow: guide catheter; violet arrow: angioplasty guide wire. Guide catheter is in left main coronary artery, guidewire and stent in left anterior descending coronary artery.
Accurate visualization of the stent position and morphology is essential for good implantation technique. Stent has to be well expanded and apposed to the vessel wall to prevent stent thrombosis. But good visualization in a moving vessel is often challenging. Selecting a good view with less of movement is a simple technique to improve visualization. Another less desirable method is to use cine mode, with a higher radiation dose.
Stent boost subtract imaging
Stent boost subtract imaging is an enhancement of the visible edge of the stent on fluoroscopy by digital management of regular X-ray images . When 58 ostial lesions in 55 patients were studied using stent boost subtract imaging and compared with intravascular ultrasound, 100% specificity and 80% sensitivity were demonstrated. Authors concluded that stent boost subtract imaging is a simple and quick method which enables improved stent location, adequate stent expansion and optimal stent strut apposition to the vessel wall. The technique can be used during percutaneous interventions involving the ostia of vessels, especially in centers where routine use of intravascular ultrasound is not feasible.
Stent boost (Philips Medical Systems) produces an enhanced stent image from 20 cine frames over 3 s using the radiopaque markers of the stent delivery balloon as an reference to align the stent between the frames in a moving vessel. The imaging is done after deflation of the stent balloon. The StentOptimizer system then automatically captures the images to create an image of the stent with enhanced edges .