Educational Exhibit Abstract No. 380 - Optical coherence tomography in interventional radiology

Abstract

Learning Objectives Understand the theory and mechanisms of optical coherence tomography (OCT) 2. Explain the benefits of OCT compared with other imaging modalities 3. Describe how OCT is performed, emphasizing intravascular techniques Background OCT, a type of optical tomography (OT), has emerging applications in interventional radiology. In OT, light transmitted through objects is measured for volumetric imaging models. In OCT, near-infrared light is used, allowing deeper tissue penetration. OCT has been referred to as “optical ultrasound,” whereby reflections of light from within tissues are imaged, yielding cross-sectional data. OCT images subsurface tissue morphology at near-microscopic resolution higher than US or MRI. OCT is live and uses no ionizing radiation. Tissue depth is limited to 3 mm due to light scatter. Previously, OCT was used to image the retina and characterize atherosclerotic plaque in vivo. In peripheral vascular disease, OCT may be used to assess stent placement/failure and intimal disease and plaque. Nonvascular applications include oncologic imaging, for example of breast tumors via needle-based OCT devices. Clinical Findings/Procedure Details Intravascular OCT may be performed through standard 6 or 7 Fr guiding catheters. Catheters may be constructed from 3.0 or 3.2 Fr short monorail IVUS catheters, modified by inserting single mode optical fibers via the IVUS flexible shaft, terminating distally with a miniature gradient index lens and prism. OCT catheters are advanced over 0.014” guidewires to target lesions. Saline (8—10 cc), hand injected via the guiding catheter, temporarily displaces blood while images are acquired (4 or 8 fps). Video monitors display real-time OCT images during digital image archiving for later quantitation using image analysis software. The procedure and the technique will be presented as a pictorial review. Conclusion and/or Teaching Points OCT provides live volumetric imaging at near-microscopic resolution without employing ionizing radiation by collecting information about near-infrared light reflected from tissue surfaces. In the future, OCT may be employed as a catheter- or needle-based technique to assess peripheral vascular disease or tumor biology in the interventional suite.