title: Accuracy of OCT, grayscale IVUS, and their combination for the diagnosis of coronary TCFA: an ex vivo validation study.
abstract: OBJECTIVE
  This study sought to assess the accuracy of optical coherence tomography (OCT), gray-scale intravascular ultrasound (IVUS), and their combination for detecting thin-cap fibroatheromas (TCFA).
  
  
  BACKGROUND
  The extent to which the imaging characteristics of OCT and IVUS correlate with histologically defined TCFA is unknown.
  
  
  METHODS
  IVUS and OCT examinations identified focal plaques in 165 coronary arteries from 60 autopsy hearts. A total of 685 pairs of images of OCT and IVUS were compared with histology. By OCT, a TCFA was defined as a signal-poor region with diffuse borders and cap thickness <65 μm. By IVUS, a TCFA was defined by the presence of echolucent zones and/or ultrasound attenuation in areas of positive remodeling. By histology, 12 of 685 focal plaques were classified as TCFAs.
  
  
  RESULTS
  With histology as the gold standard, the sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy for OCT-derived TCFA were 100%, 97%, 41%, 100%, and 98%, respectively. The corresponding numbers for IVUS-derived TCFA were 92%, 93%, 19%, 99%, and 93%, respectively. The histological findings underlying the false positive diagnoses of OCT for TCFA included large amounts of foam cell accumulation on the luminal surface, large amounts of microcalcifications at the surface, large amounts of hemosiderin accumulation, or organized thrombus. In contrast, histological causes of mischaracterization of TCFA by IVUS were mostly TCFA. When both OCT and IVUS criteria for TCFA were required to be met, the sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy were 92%, 99%, 69%, 99%, and 99%, respectively.
  
  
  CONCLUSIONS
  In the present study, neither OCT nor IVUS were optimal to detect TCFA. The combined use of OCT and IVUS may improve TCFA detection accuracy.
authors: Cardiovascular Division, Hyogo College of Medicine, Nishinomiya, Japan. Electronic address: kfujii@hyo-med.ac.jp.
authors: Kenichi
authors: K
authors: Fujii
authors: Department of Surgical Pathology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors: Hiroyuki
authors: H
authors: Hao
authors: Cardiovascular Division, Hyogo College of Medicine, Nishinomiya, Japan.
authors: Masahiko
authors: M
authors: Shibuya
authors: Cardiovascular Division, Hyogo College of Medicine, Nishinomiya, Japan.
authors: Takahiro
authors: T
authors: Imanaka
authors: Cardiovascular Division, Hyogo College of Medicine, Nishinomiya, Japan.
authors: Masashi
authors: M
authors: Fukunaga
authors: Cardiovascular Division, Hyogo College of Medicine, Nishinomiya, Japan.
authors: Kojiro
authors: K
authors: Miki
authors: Cardiovascular Division, Hyogo College of Medicine, Nishinomiya, Japan.
authors: Hiroto
authors: H
authors: Tamaru
authors: Cardiovascular Division, Hyogo College of Medicine, Nishinomiya, Japan.
authors: Hisashi
authors: H
authors: Sawada
authors: Cardiovascular Division, Hyogo College of Medicine, Nishinomiya, Japan.
authors: Yoshiro
authors: Y
authors: Naito
authors: Division of Coronary Heart Disease, Hyogo College of Medicine, Nishinomiya, Japan.
authors: Mitsumasa
authors: M
authors: Ohyanagi
authors: Department of Surgical Pathology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
authors: Seiichi
authors: S
authors: Hirota
authors: Cardiovascular Division, Hyogo College of Medicine, Nishinomiya, Japan.
authors: Tohru
authors: T
authors: Masuyama
mesh_terms: D001344:Autopsy; D002102:Cadaver; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D066298:In Vitro Techniques; D058226:Plaque, Atherosclerotic / Q000175:diagnosis* / Q000000981:diagnostic imaging; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000379:methods*; D018084:Ultrasonography, Interventional / Q000379:methods*
keywords: intravascular ultrasound; optical coherence tomography; vulnerable plaque