Abstract 15063: What Kind of Carotid Plaque is Detected as High Intensity Signal Area in T1-weighted Image Detected by Black-blood MRI ? : a Study With Optimal Coherence Tomography During Carotid Artery Stenting Procedure
Introduction: Optimal coherence tomography (OCT) is an intravascular imaging modality to assess plaque characteristics and surface of atheroma in details. The aim of this study is to evaluate vulnerable plaques in carotid stenotic lesions which are detected as high-intensity area in T1-weighted-image by MRI (Black blood technique), using both OCT and VH-IVUS before and after carotid artery stenting (CAS).
Methods: We performed CAS in consecutive 26 patients (mean age of 76±5 years) with carotid artery stenotic lesions in which MRI detected the plaque as high intensity area. We assessed plaque at the stenotic lesions by frequency-domain OCT (Ilumien OCT imaging system) and by VH-IVUS (Eagle Eye) which classified carotid plaques into four color components: fibrous, fibro-fatty, calcium and necrotic core. In analyzing OCT images, lipid rich plaque was defined as signal intensity-poor lesion covered by signal-rich bands that correspond to fibrous cap. Thin-cap fibroatheroma (TCFA) was defined as <65μm of cap thickness. After carotid stenting, we observed tissue prolapse through stent struts, as well as optimal stent apposition or expansion.
Results: In VH-IVUS images, vulnerable plaque included 50.9±6.1% of fibrous plaque, 35.8±10.8% of fibrofatty plaque, 2.8±2.6% of calcium and 10.4±6.2% of necrotic core. In OCT images, lipid rich plaques are detected in all patients. Fibrous caps which covered the vulnerable plaque were detected by OCT in all cases, whereas TCFA were detected in 52.9% cases and ruptured fibrous cap were detected in 52.9% cases. In OCT, we observed tissue prolapse through stent struts in 47.1% cases, on the other hand, IVUS, we detected those in only 23.5% cases. In 8 cases of tissue prolapse observation with OCT, small debris in distal embolic protection device (Filter Wire EZ) was observed in 3 cases.
Conclusions: Even in carotid artery, OCT is effective in evaluating not only superficial lipid-rich plaques and fibrous caps especially TCFA but also tissue prolapse on the stents. All carotid plaques with high-intensity signal in T1-weighted image of black-blood MRI have rich lipid, and in more than 70% of these plaques have TCFA or ruptured fibrous caps.
Author Disclosures: M. Suzuki: None. A. Iwai: None. S. Ishihara: None. K. Hirai: None. Y. Hashimoto: None. H. Fujimoto: None. T. Isojima: None. M. Naito: None. H. Iwama: None. T. Nakai: None. N. Doi: None.
- © 2014 by American Heart Association, Inc.