Intravascular Ultrasound Applications to the Thoracic Aorta

Abstract

Unlike traditional cardiac ultrasound that uses an exterior probe and is limited to imaging between the patient’s ribs or a transesophageal probe, intravascular ultrasound uses a miniature ultrasound transducer mounted on the tip of a catheter. Due to its intraluminal perspective, IVUS imaging provides information that supplements angiography. Standard IVUS catheters use a 9 Fr delivery sheath and a 0.035 in. guidewire, but smaller catheters do exist like the eagle-eyed gold catheter which uses a 0.014 in. guidewire. The ultrasound transducer emits and receives signals at 12.5, 20, or 30 MHz, producing an axial image (or frame) similar to the cuts from computed tomography and magnetic resonance imaging. Sizes, Increase in MHz results in a more detailed image (“Near vision”) with a decrease in MHz resulting in more penetration with larger field of view.