Assessment of Coronary Intima - Media Thickness by Optical Coherence Tomography Comparison With Intravascular Ultrasound

Abstract

ntimal thickening is considered to be an early phase of atherosclerosis; [1][2][3][4][5] in the coronary artery it is related to coronary spasm and is of prognostic importance in patients after cardiac transplantation. 6,7 Evaluation of intimal thickening of the coronary artery is thought to be important clinically and recent advancements in intravascular ultrasound (IVUS) have enabled pathological evaluation of the wall structure of the coronary artery. [8][9][10][11][12][13][14][15] However, intimal thickening is indirectly evaluated as the intima -media thickness (IMT) by IVUS because the boundary of the intima and media cannot be distinguished completely by this method. 16 Optical coherence tomography (OCT) is a new imaging method [17][18][19][20][21][22] with a resolution of approximately 10-20 m, which is approximately 10-fold greater than that of IVUS. 23 OCT can easily identify the internal elastic laminae, which cannot be identified by IVUS. 18,19 We thus hypothesized that OCT could enable more accurate measurement of the IMT and the intimal thickness than IVUS, so the aim of the present study was to test these hypotheses. MethodsWe examined 54 randomly selected segments from 54 coronary arteries from 18 consecutive cadavers (10 males, 8 females; mean age 72±6 years). The cause of death was leukemia (n=3), lung cancer (n=3), acute myocardial infarction (n=2), pulmonary embolism (n=2), intracranial hemorrhage (n=2), liver cirrhosis (n=2), pneumonia (n=2), Circulation Journal Vol.69, August 2005and trauma (n=2). The study protocol was approved by the ethics committee of Kawasaki Medical School, and written informed consent was obtained from each family. An approximate 5-cm length of the proximal site of the 3 major coronary arteries, the left anterior descending coronary artery, left circumflex artery, and right coronary artery, were obtained from cadavers at autopsy within 3 h of death. The surrounding soft tissue was dissected from each specimen. Small arterial perforators and the branches were tied off with sutures, and the distal end of the artery was occluded with a large cork. A 7F sheath was sewn into the proximal end of the artery to complete the closed system. Phosphate-buffered saline (154 mmol/L NaCl, 10 mmol/L NaH2PO4, pH 7.4), which was kept at 37°C, was infused through the side arm of the sheath. The pressure inside the coronary artery was maintained at a physiological level (60-80 mmHg) with a sphygmomanometer connected to the infusion. OCT and IVUS ImagesAn intravascular OCT catheter (ImageWire ® , LightLab Imaging, Westford, MA, USA) and IVUS catheter (Atlantis SR Pro ® 2.5F, 40-MHz, Boston Scientific, Natick, MA, USA) were inserted through the diaphragm of the sheath. Serial OCT and IVUS images were obtained using an automatic pullback device at a rate of 0.5 mm/s. The OCT images were processed and analyzed using proprietary software from LightLab Imaging, Inc and the IVUS images were exported to commercially available image processing software (Netra 3D IVUS system, ScImage) for off-lin...

Virtual Histology Intravascular Ultrasound Compared With Optical Coherence Tomography for Identification of Thin-Cap Fibroatheroma

“…A high-resolution imaging technique including OCT may be a promising method with which to identify the thin fibrous cap of atheroma. [11][12][13] In OCT images, the fibrous cap over the necrotic core was identified as a signal-rich layer overlying a signal-poor area.…”

Invasive management without stents in selected acute coronary syndrome patients with a large thrombus burden: a prospective study of optical coherence tomography guided treatment decisions

“…OCT is a high-resolution (10 µm) endocoronary imaging technique based on near-infrared light. It provides fine in vivo analysis of the 3-layer structure of the arterial wall 13 , and of atherosclerotic lesions 14 and highly sensitive thrombus detection 15 . OCT has been used since 2005 for imaging ACS-culprit lesions 16,17 and for immediate 18 and late (neointimal cover 19,20) post-procedural stent followup.…”

Cardiac Allograft Vasculopathy Can Be Distinguished From Donor-Transmitted Coronary Atherosclerosis by Optical Coherence Tomography Imaging in a Heart Transplantation Recipient

“…However, intimal thickening is only indirectly evaluated as the intima-media thickening by IVUS because the boundary of intima and media cannot be distinguished by this method as shown also in the present case. 8) OCT is a new imaging procedure with a spatial resolution of approximately 10-20 µm, which is 10-fold greater than that of IVUS. 6) As shown in Figures 1E and H, OCT could obviously identify the layer of media as a lower-echoic line, which could not be identifi ed by IVUS.…”