title: OCT compared with IVUS in a coronary lesion assessment: the OPUS-CLASS study.
abstract: OBJECTIVE
  The aim of this study was to investigate the reliability of frequency domain optical coherence tomography (FD-OCT) for coronary measurements compared with quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS).
  
  
  BACKGROUND
  Accurate luminal measurement is expected in FD-OCT because this technology offers high resolution and excellent contrast between lumen and vessel wall.
  
  
  METHODS
  In 5 medical centers, 100 patients with coronary artery disease were prospectively studied by using angiography, FD-OCT, and IVUS. In addition, 5 phantom models of known lumen dimensions (lumen diameter 3.08 mm; lumen area 7.45 mm(2)) were examined using FD-OCT and IVUS. Quantitative image analyses of the coronary arteries and phantom models were performed by an independent core laboratory.
  
  
  RESULTS
  In the clinical study, the mean minimum lumen diameter measured by QCA was significantly smaller than that measured by FD-OCT (1.81 ± 0.72 mm vs. 1.91 ± 0.69 mm; p < 0.001) and the minimum lumen diameter measured by IVUS was significantly greater than that measured by FD-OCT (2.09 ± 0.60 mm vs. 1.91 ± 0.69 mm; p < 0.001). The minimum lumen area measured by IVUS was significantly greater than that by FD-OCT (3.68 ± 2.06 mm(2) vs. 3.27 ± 2.22 mm(2); p < 0.001), although a significant correlation was observed between the 2 imaging techniques (r = 0.95, p < 0.001; mean difference 0.41 mm(2)). Both FD-OCT and IVUS exhibited good interobserver reproducibility, but the root-mean-squared deviation between measurements was approximately twice as high for the IVUS measurements compared with the FD-OCT measurements (0.32 mm(2) vs. 0.16 mm(2)). In a phantom model, the mean lumen area according to FD-OCT was equal to the actual lumen area of the phantom model, with low SD; IVUS overestimated the lumen area and was less reproducible than FD-OCT (8.03 ± 0.58 mm(2) vs. 7.45 ± 0.17 mm(2); p < 0.001).
  
  
  CONCLUSIONS
  The results of this prospective multicenter study demonstrate that FD-OCT provides accurate and reproducible quantitative measurements of coronary dimensions in the clinical setting.
authors.affiliation: Department of Cardiovascular Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kubo
authors.affiliation: Department of Cardiovascular Medicine, Wakayama Medical University, Wakayama, Japan. Electronic address: akasat@wakayama-med.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Akasaka
authors.affiliation: Division of Cardiovascular Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Junya
authors.initials: J
authors.lastname: Shite
authors.affiliation: Department of Cardiology, Toyohashi Heart Center, Toyohashi, Japan.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: First Department of Internal Medicine, Nara Medical University, Kashihara, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Uemura
authors.affiliation: Department of Cardiology, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, 2nd Affiliated Hospital of Harbin Medical University, Harbin, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Yu
authors.affiliation: Department of Medicine, Teikyo University School of Medicine, Tokyo, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Kozuma
authors.affiliation: Department of Cardiovascular Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Hironori
authors.initials: H
authors.lastname: Kitabata
authors.affiliation: Division of Cardiovascular Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Toshiro
authors.initials: T
authors.lastname: Shinke
authors.affiliation: Department of Cardiology, Toyohashi Heart Center, Toyohashi, Japan.
authors.forename: Maoto
authors.initials: M
authors.lastname: Habara
authors.affiliation: First Department of Internal Medicine, Nara Medical University, Kashihara, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Saito
authors.affiliation: Department of Cardiology, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, 2nd Affiliated Hospital of Harbin Medical University, Harbin, People's Republic of China.
authors.forename: Jingbo
authors.initials: J
authors.lastname: Hou
authors.affiliation: Department of Medicine, Teikyo University School of Medicine, Tokyo, Japan.
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Suzuki
authors.affiliation: Lightlab Imaging/St. Jude Medical, Westford, Massachusetts.
authors.forename: Shaosong
authors.initials: S
authors.lastname: Zhang
mesh_terms: D000368:Aged; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D003331:Coronary Vessels / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D019047:Phantoms, Imaging; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000295:instrumentation; D018084:Ultrasonography, Interventional / Q000295:instrumentation
keywords: FD; IVUS; MLA; MLD; OCT; PCI; QCA; TD; coronary angiography; frequency domain; intravascular ultrasound; minimum lumen area; minimum lumen diameter; optical coherence tomography; percutaneous coronary intervention; quantitative coronary angiography; time-domain