Intravascular ultrasound imaging--in vitro and vivo validation

Intravascular ultrasound imaging is a new technique for visualizing arterial structures. The purpose of this study was twofold; first, to assess the ability of this intravascular ultrasound catheter to generate cross-sectional images of human artery segments in vitro and second, to determine the reliability of intravascular ultrasound technique in the evaluation of human arteries in vivo. For the vitro study, ultrasound images of the arteries were presented as a two-dimensional, 360 degrees display of vessel cross-section perpendicular to the long-axis of the probe. The ultrasound scanning provided an accurate description with high resolution of lumen structure and lumen-intima interface in all vessel specimens. There was a good correlation between the planimetric luminal area on the ultrasound images and the area obtained from histologic images (r = 0.92). There was also a good correlation in the plaque thickness between ultrasound and histological examination (r = 0.88). In the in vivo study, the ultrasound catheter was easily introduced, readily manipulated, and images were successfully obtained in all patients. No untoward effects were noted during manipulation of the catheter. There was a good correlation in the arterial dimension between ultrasound and angiographic measurements (r = 0.93). Thus, intravascular ultrasound imaging appears to be useful for characterizing and quantitating arterial lesions.