title: X-ray phase-contrast computed tomography of human coronary arteries.
abstract: OBJECTIVE
  The objective of this study was to assess the potential of grating-based phase-contrast computed tomography (gb-PCCT) for the detection and characterization of human coronary artery disease in an experimental ex vivo validation study.
  
  
  METHODS
  The study was approved by the institutional review board, and informed consent was obtained from all patients. Specimens were examined using a conventional low-coherence x-ray tube (40 kV) and a Talbot-Lau grating interferometer. Histopathologic assessment was used as the standard of reference. Signal characteristics of calcified, fibrous (FIB), and lipid-rich (LIP) tissue were visually and quantitatively assessed by phase-contrast Hounsfield units (HU). Conventional absorption-based HU values were also measured. Conservative measurements of diagnostic accuracy for the detection and differentiation of plaque components as well as quantitative measurements of vessel dimensions were obtained, and receiver operating characteristic curve analysis for plaque differentiation was performed.
  
  
  RESULTS
  A total of 15 coronary arteries from 5 subjects were available for analysis (386 sections). Calcified, FIB, and LIP displayed distinct gb-PCCT signal criteria. The diagnostic accuracy of gb-PCCT was high with sensitivity, specificity, and negative and positive predictive values of 0.89 or greater for all plaque components with good interrater agreement (к ≥ 0.88). In addition, quantitative measurements of vessel dimensions in gb-PCCT were strongly correlated with measurements obtained from histopathology (Pearson R ≥ 0.86). Finally, phase-contrast Hounsfield units were superior to conventional HU in differentiating FIB and LIP (receiver operating characteristic analysis, 0.86 vs. 0.77, respectively; P < 0.05).
  
  
  CONCLUSIONS
  In an ex vivo setting, gb-PCCT provides improved differentiation and quantification of coronary atherosclerotic plaque and may thus serve as a tool for nondestructive histopathology.
authors.affiliation: From the *Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich; †Physics Department & Institute for Medical Engineering, Technical University Munich, Garching; ‡Institute for Medical Information Sciences, Biometry and Epidemiology, §Center for Neuropathology, Ludwig-Maximilians-University; and ∥Division of Cardiology, Ludwig-Maximilians-University Hospital, Munich, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Hetterich
authors.forename: Marian
authors.initials: M
authors.lastname: Willner
authors.forename: Christopher
authors.initials: C
authors.lastname: Habbel
authors.forename: Julia
authors.initials: J
authors.lastname: Herzen
authors.forename: Verena S
authors.initials: VS
authors.lastname: Hoffmann
authors.forename: Sandra
authors.initials: S
authors.lastname: Fill
authors.forename: Alexander
authors.initials: A
authors.lastname: Hipp
authors.forename: Mathias
authors.initials: M
authors.lastname: Marschner
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schüller
authors.forename: Sigrid
authors.initials: S
authors.lastname: Auweter
authors.forename: Steffen
authors.initials: S
authors.lastname: Massberg
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.forename: Franz
authors.initials: F
authors.lastname: Pfeiffer
authors.forename: Tobias
authors.initials: T
authors.lastname: Saam
authors.forename: Fabian
authors.initials: F
authors.lastname: Bamberg
mesh_terms: D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D004210:Dissection; D006801:Humans; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*