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 photonprocessing 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 Xray, 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. Key Points: • 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.
Original language | English |
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Pages (from-to) | 2581-2588 |
Number of pages | 8 |
Journal | European Radiology |
Volume | 22 |
Issue number | 12 |
DOIs | |
Publication status | Published - Dec 2012 |
Externally published | Yes |
Keywords
- Atherosclerotic
- Carotid artery diseases
- MARS-CT
- Plaque
- Spectral CT
- X-Ray microtomography