title: Plaque characteristics of thin-cap fibroatheroma evaluated by OCT and IVUS.
abstract: OBJECTIVE
  The purpose of this study was to assess plaque characteristics of optical coherence tomography (OCT)-derived thin-cap fibroatheroma (TCFA) by integrated backscatter intravascular ultrasound (IB-IVUS).
  
  
  BACKGROUND
  Radiofrequency signal-derived IVUS tissue characterization technology has become clinically available and provided objective and quantitative plaque characteristics of the coronary vessel wall. Integrated backscatter IVUS is one of the tissue characterization methods that can possibly provide quantitative plaque characteristics of the OCT-derived TCFA.
  
  
  METHODS
  Eighty-one coronary lesions with plaque burden >40% were selected and analyzed with both IB-IVUS and OCT. The OCT-derived TCFA was defined as a presence of thin fibrous cap (<65 μm) overlying a signal-poor lesion with diffuse border representing a lipid-rich plaque. By conventional gray-scale IVUS, external elastic membrane (EEM) cross-sectional area (CSA), lumen CSA, plaque plus media (P+M) CSA, plaque burden and remodeling index were measured. By IB-IVUS, plaque characteristics were further classified as fibrosis, dense fibrosis, calcification, or lipid pool.
  
  
  RESULTS
  Optical coherence tomography identified 40 TCFAs (49%) and 41 non-TCFAs. The EEM CSA, P+M CSA, plaque burden, and remodeling index were significantly larger in OCT-derived TCFA than non-TCFA. By IB-IVUS, percentage lipid pool area (= lipid pool area/P+M CSA × 100) was significantly higher (62.4 ± 12.8% vs. 38.4 ± 13.1%, p<0.0001) and percentage fibrosis area (= fibrosis area/P+M CSA × 100) was significantly lower (34.6 ± 11.4% vs. 50.5 ± 8.7%, p<0.0001) in OCT-derived TCFA than non-TCFA. By receiver-operator characteristic curve analysis, percentage lipid pool area ≥55%, percentage fibrosis area ≤41%, and remodeling index ≥1.0 were predictors of OCT-derived TCFA.
  
  
  CONCLUSIONS
  The OCT-derived TCFA had larger plaque burden and positive remodeling with predominant lipid component and less fibrous plaque assessed by IB-IVUS.
authors.affiliation: Department of Cardiology, Kawasaki Medical School, Kurashiki, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Miyamoto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Okura
authors.forename: Teruyoshi
authors.initials: T
authors.lastname: Kume
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kawamoto
authors.forename: Yoji
authors.initials: Y
authors.lastname: Neishi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Hayashida
authors.forename: Ryotaro
authors.initials: R
authors.lastname: Yamada
authors.forename: Koichiro
authors.initials: K
authors.lastname: Imai
authors.forename: Ken
authors.initials: K
authors.lastname: Saito
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Yoshida
mesh_terms: D000368:Aged; D002114:Calcinosis / Q000175:diagnosis; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D005355:Fibrosis; D006801:Humans; D007564:Japan; D016014:Linear Models; D008055:Lipids / Q000032:analysis; D008297:Male; D008875:Middle Aged; D058226:Plaque, Atherosclerotic / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D011237:Predictive Value of Tests; D012372:ROC Curve; D012720:Severity of Illness Index; D041623:Tomography, Optical Coherence; D018084:Ultrasonography, Interventional
chemical_list: D008055:Lipids