Summary : The traditional approach to percutaneous coronary revascularization employs visual assessment by fluoroscopy and angiography; yet the angiographic assessment of lesion severity, vessel morphology, calcification, dissection and thrombus is subjective and difficult to quantitate. In the 1990’s, intravascular ultrasound was established as an important complementary imaging modality for diagnostic and interventional cardiac catheterization. IVUS represents a radically different approach to vascular anatomy: Unlike angiography, which displays the coronary artery as a silhouette of the contrast-filled lumen, IVUS generates a cross-sectional tomographic image of the lumen and vessel wall. Few years ago, stents have become an essential part of the catheterization. Laboratory, and a dominant technique in interventional cardiology world wide. Because of the radiolucent characteristics of the stent metal struts, angiographic imaging techniques often do not provide adequate information to evaluate accurately the stent geometry in the target segment. IVUS can provide precise tomographic information and detailed relationship between the stent struts, that is highly echogenic, and the plaque and vessel wall morphology. It is well appreciated that IVUS guided stenting is more accurate in achieving optimal stent expansion. Several studies have concluded that QCA failed to predict optimal stent deployment as depicted by IVUS criteria in 30-80% of cases. IVUS studies have revealed that the majority of cases with suboptimal stent deployment is due to under expansion, which is mostly due to underestimation of the actual vessel size by QCA, the use of undersized balloon or the application of low inflation pressures. Stent malappostion accounts for 10% of the cases, in addition to asymmetrical stent deployment (due to difference in plaque resistance e.g. calcification or asymmetrical balloon inflation. IVUS leads to improved stent expansion as it ultimately guides operators for # pretreatment of lesions poorly expandable “R.B, DCA, cutting balloon”, #optimal selection of balloon diameter and length for stent deployment, #assessment of stent expansion and edge lesions after stent deployment and #achievement of complete stent apposition to the vessel wall. Colombo, et al, on demonstrating that stent under expansion is present in 80% of cases studied by IVUS, have set the new standards of high pressure stent deployment which is the main-stay of today’s practice. The application of high pressure is associated with more symmetrical stent expansion and larger in-stent minimal lumen diameter which lead to the improvement of the acute results and reduction of early complications. However, after high pressure stent expansion and with optimal angiographic results, IVUS guidance lead to further interventions in 30-50% of the cases. Despite these salutary benefits of IVUS-guided stent deployment, it can not be performed to all cases due to the additional cost of the procedure, specially in developing countries with tight economic resources.