Intravascular Ultrasonic Assessment of Lumen Geometry and Distensibility of the Angiographically Normal Artery: A Correlation with Quantitative Angiography

The feasibility of assessing lumen diameter and area using a 30‐MHz mechanically driven ultrasound imaging device was evaluated in vitro in phantoms and in vivo in eight human arteries (six iliac, two brachial). Ultrasound data were compared to angiographic data derived from the cardiovascular angiographic analysis system. In addition, the change of lumen area in a given cardiac cycle was determined in each patient. A close relation between ultrasound and angiography was observed in the phantom studies. In the first three patients there was disagreement; ultrasound images showed larger values compared to the angiographically derived values. Disagreement was related to the use of nominal measurements of the sheath supplied by the manufacturer as calibration. Data on the five other patients showed a close relation between the values derived with ultrasound and angiography. The arterial lumen area revealed a 5%± 2% change during one cardiac cycle. The intra‐ and interobserver variability test showed good correlation for the ultrasound study. This study demonstrates that intravascular ultrasound is an accurate and reproducible technique to measure vascular diameter, lumen area, and arterial wall distensibility in vivo.