title: Contrast enhancement of coronary atherosclerotic plaque: a high-resolution, multidetector-row computed tomography study of pressure-perfused, human ex-vivo coronary arteries.
abstract: OBJECTIVE
  The objective of this study was to investigate the effect of contrast injection on atherosclerotic coronary plaque attenuation measured using multidetector-row computed tomography.
  
  
  BACKGROUND
  Recent multidetector-row computed tomography studies have described the characterization of coronary atherosclerotic plaque on the basis of Hounsfield unit values. The influence of contrast injection on the attenuation of individual plaque components, however, is unknown.
  
  
  METHODS
  Using a pressurized perfusion system, 10 human coronary arteries were examined postmortem with multidetector-row computed tomography and histology. Pre-enhanced, peak-enhanced, and delayed enhanced multidetector-row computed tomography images were acquired during continuous perfusion of the vessel. A total of 37 focal atherosclerotic plaques were identified. Vessel wall attenuation was measured from multidetector-row computed tomography images during all three enhancement phases. On the basis of the histology, plaques were categorized as noncalcified (predominantly fibrous or predominantly fibrofatty), mixed calcified (calcified fibrous or calcified necrotic core), or densely calcified. The mean Hounsfield unit was compared among contrast phases for all plaques and in plaque subgroups.
  
  
  RESULTS
  We observed contrast enhancement of atherosclerotic plaques within the vessel wall. For noncalcified plaques including both fibrous and fibrofatty plaques, the mean Hounsfield unit of the vessel wall during and after contrast injection exceeded the mean value before injection (t-test, P<0.002).
  
  
  CONCLUSIONS
  The present study demonstrates that intra-arterial injection of iodinated contrast agent results not only in luminal enhancement but also in atherosclerotic plaque enhancement in pressure-perfused coronary arteries imaged ex vivo. Plaque enhancement should be considered when characterizing plaque components on the basis of Hounsfield unit with multidetector-row computed tomography.
authors.affiliation: Section of Cardiovascular Imaging, Division of Radiology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA. hallibs@ccf.org
authors.forename: Sandra S
authors.initials: SS
authors.lastname: Halliburton
authors.forename: Paul
authors.initials: P
authors.lastname: Schoenhagen
authors.forename: Anuja
authors.initials: A
authors.lastname: Nair
authors.forename: Arthur
authors.initials: A
authors.lastname: Stillman
authors.forename: Michael
authors.initials: M
authors.lastname: Lieber
authors.forename: E
authors.initials: E
authors.lastname: Murat Tuzcu
authors.forename: D
authors.initials: D
authors.lastname: Geoffrey Vince
authors.forename: Richard D
authors.initials: RD
authors.lastname: White
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D006801:Humans; D066298:In Vitro Techniques; D007472:Iohexol / Q000031:analogs & derivatives*; D008875:Middle Aged; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide