Intravascular ultrasound imaging: in vivo peripheral and coronary artery studies

Recent in vitro studies have demonstrated that intravascular ultrasound can obtain high-resolution cross-sectional images of arterial vessels. To further expand the use of this technique for in vivo visualization of peripheral and coronary vessels, we imaged 24 femoral and 13 carotid arteries from 19 sheep. Using a manual rotation technique, high-resolution images were obtained in 95% of the vessel sites with a rigid probe and in 82% of the vessel sites with a flexible catheter. In 14 of these arteries, good correlation was found between the lumen diameter measured by ultrasound and by angiography (P less than .001, r = .91). In addition, 6 left circumflex coronary arteries were imaged from 6 additional sheep by motor-driven rotation of the ultrasound probe at 1,800 rotations per minute, obtaining clear delineation of coronary lumen morphology and lumen-intima interface. Strong correlation was found also between intravascular ultrasound and cineangiography for coronary artery diameter measurement (P less than .001, r = .96). These studies demonstrate that this technique can provide high-resolution images of arterial vessels in vivo and may have unique advantages in diagnosis of atherosclerotic vascular disease and in the guidance of new catheter-based therapeutic modalities.