Coronary intravascular ultrasound (IVUS): Coronary intravascular ultrasound (IVUS) uses small catheters with ultrasound transducers at the tip to image the coronary arteries with ultrasound from within the lumen. The special catheters can be introduced through a guide catheter into the main coronary arteries. They are then connected to the the ultrasound equipment kept in the console. Imaging is done as the catheter is pulled back and recorded. It is very useful to detect abnormalities in the vessel wall which can be missed by conventional coronary angiography. When a coronary stent has been implanted, IVUS imaging is very helpful to check whether all parts of the stent has been well apposed to the vessel wall.