IVUS is an intravascular ultrasonographic auxiliary imaging method. 

IVUS stands for intravascular ultrasound and is a type of medical imaging technique. IVUS is a technology used to visualize structures inside the vessel (intravascular) using ultrasound waves. This is often used to diagnose and treat vascular diseases such as coronary artery disease. 
During an IVUS procedure, a catheter (a thin tube) is inserted into the vessel and an ultrasound probe is moved through the vessel. Ultrasound waves are used to image the internal structure of the vein in high resolution. This allows the camera to view all layers of the vein at a 360-degree angle.  This provides doctors with important information about the thickness of the vessel wall, plaque build-up, blockages and other vascular diseases.

In Which Situations Is IVUS Used?

IVUS is used to make decisions and direct treatment in cases where coronary angiography is not sufficient. Coronary angiography is used as a gold standard method in cardiovascular diseases, especially in the diagnosis of stenosis and occlusion in the coronary arteries, and it is mostly adequate. However, a very clear decision must be made in main vessel interventions, especially in interventions performed in the left main coronary vessels that supply two of three of the heart. Coronary angiography is often insufficient when deciding on information such as the diameter and length of the stent to be implanted and where the stent should be extended. Therefore, these procedures are performed under IVUS guidance.  In international guidelines and consensus reports on this subject, it is recommended to use the IVUS method in certain vascular interventions.

What is the Difference Between Coronary Angiography and IVUS?

Coronary angiography and IVUS (intravenous ultrasound) are two different methods. Coronary angiography is a two-dimensional visualization of the vessel by administering contrast material to make the vessel visible with the help of an angiography device. However, intravascular ultrasound (IVUS) provides 360-degree visualization of the inside of the vessel. In fact, coronary angiography and IVUS are two complementary methods. Conditions such as calcification in the vessel, small tears, the actual diameter of the vessel, and the characteristics of the lesions cannot be seen with angiography, but become more clearly visible with IVUS. For this reason, IVUS (intravenous ultrasound) and coronary angiography are applied when details are needed.

How is IVUS Performed?

IVUS is performed during coronary angiography. A thin catheter (tube) is inserted into the artery and advanced along the vessels. An IVUS probe that can be moved forward is attached to the tip of the catheter. The IVUS probe is moved through the vessel and sends out ultrasound waves. The reflected waves are processed by a computer to create detailed intravascular images. The images are viewed in real time on a monitor. The doctor assesses the internal structure of the vessel, plaque build-up, blockages and other important information.

After the procedure, the IVUS catheter is pulled backwards from the end point of the vessel to the starting point, defined as pull back. This procedure plays an important role in the diagnosis, treatment and follow-up of vascular diseases.