This study compares the ability of intravascular optical coherence tomography (OCT) and high-frequency intravascular ultrasound (IVUS) to image highly stenotic human coronary arteries in vitro. Current imaging modalities have insufficient resolution to perform risk stratification based on coronary plaque morphology. OCT is a new technology capable of imaging at a resolution of 5 to 20 μm, which has demonstrated the potential for coronary arterial imaging in prior experiments. Human postmortem coronary arteries with severely stenotic segments were imaged with catheter-based OCT and IVUS. The OCT system had an axial resolution of 20 μm and a transverse resolution of 30 μm. OCT was able to penetrate and image near-occlusive coronary plaques. Compared with IVUS, these OCT images demonstrated superior delineation of vessel layers and lack of ring-down artifact, leading to clearer visualization of the vessel plaque and intima. Histology confirmed the accuracy and high contrast of vessel layer boundaries seen on OCT images. Thus, catheter-based OCT systems are able to image near-occlusive coronary plaques with higher resolution than that of IVUS.
This study was supported in part by contracts NIH-RO1-AR44812-01, NIH-9-RO1-CA75289-01, NIH-9-RO1-EY11289-10, and NIH-1-R29-HL55686-01A1 from the National Institutes of Health, Bethesda, Maryland; and contract 96-0205 from the Whitaker Foundation. Manuscript received May 13, 1999; revised manuscript received and accepted October 20, 1999.