Incomplete stent apposition can be detected by intravascular ultrasound (IVUS). In case the balloon has fractured the plaque, but stent has not expanded fully, contrast will fill the space between stent and the arterial lumen and lack of apposition may not be evident on angiography. IVUS will detect this and post dilatation can be adviced, resulting in good stent apposition and lesser late lumen loss. STARS and TULIP trials have demonstrated lesser restenosis in IVUS guided stenting.
IVUS is also useful to find the cause of residual haziness in the stented region – it could be poor dilatation or thrombus, which can be differentiated by IVUS.