A forward-viewing intravascular ultrasound catheter suitable for intracoronary use

Current intravascular ultrasound (IVUS) catheters provide a transverse cross-sectional view of the blood vessel, thus limiting their ability to visualize severely stenosed or occluded vessels. Forward-viewing IVUS devices can overcome these limitations. Previously described forward-viewing IVUS catheters are mechanically complex, making them too bulky for use in coronary arteries. A new design for small-forward viewing IVUS catheters was developed. Using this design, flexible 5-Fr (1.6 mm diameter) and 8-Fr (2.6 mm diameter) prototype catheters up to 110 cm long, suitable for intravascular work, were constructed. Imaging of cadaver arterial segments was performed using these prototype catheters. Structures such as branches and plaque and features such as calcium were well seen with these catheters. Correlation of lumen dimensions measured with the IVUS catheters and by histology (HIST) was excellent: IVUS = 1.06 x HIST - 1.45 mm, r2 = 0.98. This new technology holds promise as a tool for guiding intravascular interventions.