title: AHA classification of coronary and carotid atherosclerotic plaques by grating-based phase-contrast computed tomography.
abstract: OBJECTIVE
  To evaluate the potential of grating-based phase-contrast computed-tomography (gb-PCCT) to classify human carotid and coronary atherosclerotic plaques according to modified American Heart Association (AHA) criteria.
  
  
  METHODS
  Experiments were carried out at a laboratory-based set-up consisting of X-ray tube (40 kVp), grating-interferometer and detector. Eighteen human carotid and coronary artery specimens were examined. Histopathology served as the standard of reference. Vessel cross-sections were classified as AHA lesion type I/II, III, IV/V, VI, VII or VIII plaques by two independent reviewers blinded to histopathology. Conservative measurements of diagnostic accuracies for the detection and differentiation of plaque types were evaluated.
  
  
  RESULTS
  A total of 127 corresponding gb-PCCT/histopathology sections were analyzed. Based on histopathology, lesion type I/II was present in 12 (9.5 %), III in 18 (14.2 %), IV/V in 38 (29.9 %), VI in 16 (12.6 %), VII in 34 (26.8 %) and VIII in 9 (7.0 %) cross-sections. Sensitivity, specificity and positive and negative predictive value were ≥0.88 for most analyzed plaque types with a good level of agreement (Cohen's kappa = 0.90). Overall, results were better in carotid (kappa = 0.97) than in coronary arteries (kappa = 0.85). Inter-observer agreement was high with kappa = 0.85, p < 0.0001.
  
  
  CONCLUSIONS
  These results indicate that gb-PCCT can reliably classify atherosclerotic plaques according to modified AHA criteria with excellent agreement to histopathology.
  
  
  CONCLUSIONS
  • Different atherosclerotic plaque types display distinct morphological features in phase-contrast CT. • Phase-contrast CT can detect and differentiate AHA plaque types. • Calcifications caused streak artefacts and reduced sensitivity in type VI lesions. • Overall agreement was higher in carotid than in coronary arteries.
authors.affiliation: Institute of Clinical Radiology, Ludwig-Maximilian University Hospital, Marchioninistraße 15, 81377, Munich, Germany. Holger.Hetterich@med.uni-muenchen.de.
authors.forename: Holger
authors.initials: H
authors.lastname: Hetterich
authors.affiliation: Institute of Clinical Radiology, Ludwig-Maximilian University Hospital, Marchioninistraße 15, 81377, Munich, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Webber
authors.affiliation: Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany.
authors.forename: Marian
authors.initials: M
authors.lastname: Willner
authors.affiliation: Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Herzen
authors.affiliation: Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany.
authors.forename: Lorenz
authors.initials: L
authors.lastname: Birnbacher
authors.affiliation: Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Hipp
authors.affiliation: Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Marschner
authors.affiliation: Institute of Clinical Radiology, Ludwig-Maximilian University Hospital, Marchioninistraße 15, 81377, Munich, Germany.
authors.forename: Sigrid D
authors.initials: SD
authors.lastname: Auweter
authors.affiliation: Institute of Clinical Radiology, Ludwig-Maximilian University Hospital, Marchioninistraße 15, 81377, Munich, Germany.
authors.forename: Christopher
authors.initials: C
authors.lastname: Habbel
authors.affiliation: Center for Neuropathology, Ludwig-Maximilian University Hospital, Munich, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schüller
authors.affiliation: Institute of Clinical Radiology, Ludwig-Maximilian University Hospital, Marchioninistraße 15, 81377, Munich, Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: Bamberg
authors.affiliation: Institute of Clinical Radiology, Ludwig-Maximilian University Hospital, Marchioninistraße 15, 81377, Munich, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Ertl-Wagner
authors.affiliation: Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany.
authors.forename: Franz
authors.initials: F
authors.lastname: Pfeiffer
authors.affiliation: Institute of Clinical Radiology, Ludwig-Maximilian University Hospital, Marchioninistraße 15, 81377, Munich, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Saam
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000572:American Heart Association; D002339:Carotid Arteries / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D058226:Plaque, Atherosclerotic / Q000145:classification* / Q000000981:diagnostic imaging* / Q000473:pathology; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014481:United States
keywords: Atherosclerosis; Cardiac imaging techniques; Carotid arteries; Computed x-ray tomography; Coronary vessels