Digital enhancement of stent images in primary and secondary percutaneous coronary revascularisation

Inadequate stent expansion and apposition during percutaneous coronary intervention increases the risk of subsequent restenosis and thrombosis. In repeat and complex percutaneous interventions, such as treatment of stent restenosis or bifurcation techniques, these aspects present a renewed importance. Intravascular ultrasound (IVUS) constitutes the standard technique to assess stent expansion, but its use in clinical practice is far from being universal. Although most current stent designs are radiolucent, new radiological imaging modalities, specifically tailored to coronary stent imaging, can render images with enough quality to visualise stent sub-expansion. While this approach might be complementary to IVUS in clinical practice, few in vivo studies comparing both techniques are available. In this article we review the principles of digital enhancement of stent images and the available validation studies. Furthermore, we report on a comparison between IVUS and digital enhancement stent images performed after coronary stenting.