INTRAVASCULAR ULTRASOUND
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| Plate 3-11 |
Intravascular ultrasound (IVUS) uses high-frequency sound waves to acquire 3D images to determine the extent and composition of the atherosclerotic lesions in the coronary vessels. IVUS is an invasive technique used in the catheterization laboratory to complement catheter based coronary angiography and thus requires cardiac catheterization.
A small wire
with an echocardiographic transducer at the tip is passed into the coronary
artery by way of the cardiac catheter (see Plate 3-11). High-frequency sound waves produce pictures of the arterial wall and any
pathology seen in the wall, such as a clot, cholesterol, calcium, or disruption
of the endothelium. Both IVUS and angiography can evaluate the length and
severity of stenosis, but IVUS adds assessment of the vascular wall, including
plaque morphology and cross-sectional area of the stenosis and layers of the
vessel wall. IVUS is useful for clinical decision making on whether a patient
needs an intracoronary interventional procedure when catheter-based assessment
of stenotic severity is equivocal.
Intravenous
ultrasound combined with angiography and fractional flow and coronary flow
reserve provides a complete assessment of the anatomy and physiology of the
blood vessel. The cardiologist uses this information in management of the
patient, including effectiveness of aggressive cholesterol lowering and
assessment of proper stent deployment after angioplasty.
