Application of a new phased-array ultrasound imaging catheter in the assessment of vascular dimensions. In vivo comparison to cineangiography.

Tomographic imaging techniques such as ultrasound can provide important information in the evaluation of vascular anatomy. Recent technical advances have permitted fabrication of a small (1.83 mm), phased-array, intravascular ultrasonic imaging catheter capable of continuous real-time, cross-sectional imaging of blood vessels. We used this imaging catheter to compare intraluminal ultrasound with cineangiography in the measurement of vascular dimensions in animals and to assess the intraobserver and interobserver variability of the technique. Segmental deformation of vessel anatomy was produced by stenoses created with a tissue ligature or by balloon dilation. The mean value for measurements of vessel diameter was 5.6 mm by cineangiography and 5.7 mm by intravascular ultrasound. The correlation between cineangiography and ultrasound was close (r = 0.98). Mean cross-sectional area by angiography was 28.8 mm2 and 29.6 mm2 (r = 0.96) by ultrasound. Percent diameter reduction produced by the stenoses averaged 48.4% by cineangiography and 40.1% by ultrasound, and the two methods correlated closely (r = 0.89). Correlation between cineangiography and ultrasound for vessel diameter and area before balloon dilation was closer (r = 0.92 and 0.88) than after balloon dilation (r = 0.86 and 0.81). This difference reflected an increase in measured vessel eccentricity following balloon dilation. These data demonstrate that intravascular ultrasound is an accurate and reproducible method for measurement of vascular diameter and cross-sectional area in vivo. Intravascular ultrasound is capable of accurately identifying and quantifying segmental deformation of vascular dimensions produced by either stenoses or balloon dilation.