title: Spectral CT of carotid atherosclerotic plaque: comparison with histology.
abstract: OBJECTIVE
  To distinguish components of vulnerable atherosclerotic plaque by imaging their energy response using spectral CT and comparing images with histology.
  
  
  METHODS
  After spectroscopic calibration using phantoms of plaque surrogates, excised human carotid atherosclerotic plaques were imaged using MARS CT using a photon-processing detector with a silicon sensor layer and microfocus X-ray tube (50 kVp, 0.5 mA) at 38-μm voxel size. The plaques were imaged, sectioned and re-imaged using four threshold energies: 10, 16, 22 and 28 keV; then sequentially stained with modified Von Kossa, Perl's Prussian blue and Oil-Red O, and photographed. Relative Hounsfield units across the energies were entered into a linear algebraic material decomposition model to identify the unknown plaque components.
  
  
  RESULTS
  Lipid, calcium, iron and water-like components of plaque have distinguishable energy responses to X-ray, visible on spectral CT images. CT images of the plaque surface correlated very well with histological photographs. Calcium deposits (>1,000 μm) in plaque are larger than iron deposits (<100 μm), but could not be distinguished from each other within the same voxel using the energy range available.
  
  
  CONCLUSIONS
  Spectral CT displays energy information in image form at high spatial resolution, enhancing the intrinsic contrast of lipid, calcium and iron within atheroma.
  
  
  CONCLUSIONS
  Spectral computed tomography offers new insights into tissue characterisation. Components of vulnerable atherosclerotic plaque are spectrally distinct with intrinsic contrast. Spectral CT of excised atherosclerotic plaques can display iron, calcium and lipid. Calcium deposits are larger than iron deposits in atheroma. Spectral CT may help in the non-invasive detection of vulnerable plaques.
authors: Department of Physics and Astronomy, University of Canterbury, Christchurch, New Zealand.
authors: R
authors: R
authors: Zainon
authors: J P
authors: JP
authors: Ronaldson
authors: T
authors: T
authors: Janmale
authors: N J
authors: NJ
authors: Scott
authors: T M
authors: TM
authors: Buckenham
authors: A P H
authors: AP
authors: Butler
authors: P H
authors: PH
authors: Butler
authors: R M
authors: RM
authors: Doesburg
authors: S P
authors: SP
authors: Gieseg
authors: J A
authors: JA
authors: Roake
authors: N G
authors: NG
authors: Anderson
mesh_terms: D002118:Calcium / Q000378:metabolism; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D003287:Contrast Media; D006801:Humans; D066298:In Vitro Techniques; D007472:Iohexol / Q000031:analogs & derivatives; D007501:Iron / Q000378:metabolism; D050356:Lipid Metabolism; D019047:Phantoms, Imaging; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology; D011857:Radiographic Image Interpretation, Computer-Assisted; D013194:Staining and Labeling; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide; D007501:Iron; D002118:Calcium