title: Ex Vivo Assessment of Coronary Atherosclerotic Plaque by Grating-Based Phase-Contrast Computed Tomography: Correlation With Optical Coherence Tomography.
abstract: The aim of this study was to determine the diagnostic accuracy of grating-based phase-contrast computed tomography (gb-PCCT) to classify and quantify coronary vessel characteristics in comparison with optical coherence tomography (OCT) and histopathology in an ex vivo setting.
  
  
  
  After excision from 5 heart specimens, 15 human coronary arteries underwent gb-PCCT examination using an experimental imaging setup consisting of a rotating molybdenum anode x-ray tube, a Talbot-Lau grating interferometer, and a single photon counting detector. Subsequently, all vessels were imaged by OCT and histopathologically processed. Optical coherence tomography, gb-PCCT, and histopathology images were manually matched using anatomical landmarks. Optical coherence tomography and gb-PCCT were reviewed by 2 independent observers blinded to histopathology. Vessel, lumen, and plaque area were measured, and plaque characteristics (lipid rich, calcified, and fibrous) were determined for each section. Measures of diagnostic accuracy were derived, applying histopathology as the standard of reference.
  
  
  
  Of a total of 286 assessed cross sections, 241 corresponding sections were included in the statistical analysis. Quantitative measures derived from gb-PCCT were significantly higher than from OCT (P < 0.001) and were strongly correlated with histopathology (Pearson r ≥0.85 for gb-PCCT and ≥0.61 for OCT, respectively). Results of Bland-Altman analysis demonstrated smaller mean differences between OCT and histopathology than for gb-PCCT and histopathology. Limits of agreement were narrower for gb-PCCT with regard to lumen area, for OCT with regard to plaque area, and were comparable with regard to vessel area. Based on histopathology, 228/241 (94.6%) sections were classified as fibrous, calcified, or lipid rich. The diagnostic accuracy of gb-PCCT was excellent for the detection of all plaque components (sensitivity, ≥0.95; specificity, ≥0.94), whereas the results for OCT showed sensitivities of ≥0.73 and specificities of ≥0.66.
  
  
  
  In this ex vivo setting, gb-PCCT provides excellent results in the assessment of coronary atherosclerotic plaque characteristics and vessel dimensions in comparison to OCT and histopathology. Thus, the technique may serve as adjunct nondestructive modality for advanced plaque characterization in an experimental setting.
authors.affiliation: From the *Institute of Clinical Radiology, Ludwig-Maximilian University; †German Center for Cardiovascular Disease Research (DZHK e.V.), Munich; ‡Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching; §German Heart Center of the State of Bavaria and the Technical University Munich; ∥Center for Neuropathology, Ludwig-Maximilian University, Munich; ¶Institute of Neuropathology, University Medical Center Hamburg-Eppendorf; #Research Institute Children's Cancer Center; **Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Hamburg; ††Institute for Medical Information Sciences, Biometry and Epidemiology, Ludwig-Maximilian University, Munich; ‡‡Medizinische Klinik I and Poliklinik, Ludwig-Maximilian University, Munich; and §§Department of Diagnostic and Interventional Radiology, University of Tübingen, Tübingen, Germany.
authors.forename: Christopher
authors.initials: C
authors.lastname: Habbel
authors.forename: Holger
authors.initials: H
authors.lastname: Hetterich
authors.forename: Marian
authors.initials: M
authors.lastname: Willner
authors.forename: Julia
authors.initials: J
authors.lastname: Herzen
authors.forename: Kristin
authors.initials: K
authors.lastname: Steigerwald
authors.forename: Sigrid
authors.initials: S
authors.lastname: Auweter
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schüller
authors.forename: Jörg
authors.initials: J
authors.lastname: Hausleiter
authors.forename: Steffen
authors.initials: S
authors.lastname: Massberg
authors.forename: Maximilian
authors.initials: M
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: D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging; D004210:Dissection; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D041623:Tomography, Optical Coherence / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*