title: Reproducibility of intravascular ultrasound radiofrequency data analysis (virtual histology) with a 45-MHz rotational imaging catheter in ex vivo human coronary arteries.
abstract: BACKGROUND
  Despite the frequent use of spectral analysis of intravascular ultrasound radiofrequency data (VH(®) IVUS) in clinical studies, the assessment for reproducibility using this with high frequency IVUS remains unexplored.
  
  
  OBJECTIVE
  The aim of this study was to examine the reproducibility of VH IVUS using 45-MHz rotational IVUS in ex vivo human coronary arteries.
  
  
  METHODS
  Data were collected using 45-MHz VH IVUS (Revolution(®), Volcano Corporation, San Diego, CA, USA) via a series of pullbacks from eight human coronary artery specimens. Imaging data were analyzed by two independent observers. Intraobserver and interobserver reproducibility were assessed using five pullbacks from five vessels. The intercatheter reproducibility was assessed using three different catheters in each of the five vessels. The intracatheter reproducibility was assessed between the two sequential pullbacks from each of the 15 catheters used in the intercatheter assessment.
  
  
  RESULTS
  Geometrical measurements consistently showed low variability (relative difference <10%) and excellent intraclass correlation coefficients (ICCs), ranging from 0.88 to 1.00. With respect to the compositional measurements, the relative differences were predominantly higher than those of geometrical measurements. In particular, fibrous-fatty area showed a higher relative difference (17.5% in intercatheter assessment) compared to fibrous, necrotic core, and dense calcium areas (6.5%, 8.4%, and 6.4%, respectively). However, each compositional measurement also showed acceptable reproducibility (ICCs ranging from 0.82 to 1.00).
  
  
  CONCLUSIONS
  The 45-MHz rotational VH IVUS technology had acceptable reproducibility with respect to geometrical and compositional assessments in ex vivo human coronary arteries. These data are crucial when designing future longitudinal studies addressing geometrical measurements and plaque characterization by 45-MHz VH IVUS.
authors.affiliation: Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands; Department of Cardiology, Fujita Health University Hospital, Toyoake, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Muramatsu
authors.affiliation: Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands; Cardialysis B.V., Rotterdam, The Netherlands. Electronic address: hgarcia@cardialysis.nl.
authors.forename: Hector M
authors.initials: HM
authors.lastname: García-García
authors.affiliation: Department of Cardiology, Thorax Institute, Hospital Clinic, Barcelona, Spain.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Brugaletta
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kosin University Gospel Hospital, Busan, South Korea.
authors.forename: Jung Ho
authors.initials: JH
authors.lastname: Heo
authors.affiliation: Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Onuma
authors.affiliation: Biomedical Engineering Department, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Russell J
authors.initials: RJ
authors.lastname: Fedewa
authors.affiliation: Volcano Corporation, Rancho Cordova, CA, USA.
authors.forename: Anuja
authors.initials: A
authors.lastname: Nair
authors.affiliation: Department of Cardiology, Fujita Health University Hospital, Toyoake, Japan. Electronic address: ozakiyuk@fujita-hu.ac.jp.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Ozaki
authors.affiliation: Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Serruys
mesh_terms: D062906:Cardiac Catheters; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D019160:Endosonography / Q000295:instrumentation / Q000379:methods; D006801:Humans; D008875:Middle Aged; D015588:Observer Variation; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D012399:Rotation; D018084:Ultrasonography, Interventional / Q000295:instrumentation* / Q000379:methods*
keywords: Coronary artery disease; Ex vivo; Intravascular ultrasound; Reproducibility; Virtual histology