Spectroscopic (multi-energy) CT distinguishes iodine and barium contrast material in MICE
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Spectral CT differs from dual-energy CT by using a conventional X-ray tube and a photon-counting detector. We wished to produce 3D spectroscopic images of mice that distinguished calcium, iodine and barium.
We developed a desktop spectral CT, dubbed MARS, based around the Medipix2 photon-counting energy-discriminating detector. The single conventional X-ray tube operated at constant voltage (75 kVp) and constant current (150 µA). We anaesthetised with ketamine six black mice (C57BL/6). We introduced iodinated contrast material and barium sulphate into the vascular system, alimentary tract and respiratory tract as we euthanised them. The mice were preserved in resin and imaged at four detector energy levels from 12 keV to 42 keV to include the K-edges of iodine (33.0 keV) and barium (37.4 keV). Principal component analysis was applied to reconstructed images to identify components with independent energy response, then displayed in 2D and 3D.
Iodinated and barium contrast material was spectrally distinct from soft tissue and bone in all six mice. Calcium, iodine and barium were displayed as separate channels on 3D colour images at <55 µm isotropic voxels.
Spectral CT distinguishes contrast agents with K-edges only 4 keV apart. Multi-contrast imaging and molecular CT are potential future applications.
KeywordsMedipix CT spectroscopy Spectral CT K-edge imaging Contrast material Photon counting detector
We thank the Medipix2 and Medipix3 collaborations and European Organisation for Nuclear Research (CERN) for use of the Medipix detectors; Graeme Kershaw for fixing the mice in the resin; Judith Dawson for help preparing the manuscript; Steffi Girst for dose estimation.
This work was supported by FRST-Man grant PROJ-13860-NMTS-UOC.
This information was presented at the European Congress of Radiology, March, 2009
- 1.Firsching M, Niederlohner D, Michel T, Anton G (2006) Quantitative material reconstruction in CT with spectroscopic X-ray pixel detectors—a simulation study. IEEE Nucl Sci Symp Conf Rec 4:2257–2259 accessed at http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=4179477&isnumber=4179395 CrossRefGoogle Scholar
- 5.Schültke E, Fiedler S, Nemoz C, Ogieglo L, Kelly ME, Crawford P, Esteve F, Brochard T, Renier M, Requardt H, Le Duc G, Juurlink B, Meguro K (2009) Synchrotron-based intra-venous K-edge digital subtraction angiography in a pig model: a feasibility study. Eur J Radiol, epub Feb 28, doi: 10.1016/j.ejrad.2009.01.019
- 6.Hubbell JH, Seltzer SM (eds) (1995) Tables of x-ray mass attenuation coefficients and mass-energy absorption coefficients. In: Physical Reference Data. NIST Standard Reference Database 126. Available via http://physics.nist.gov/PhysRefData/XrayMassCoef/cover.html. Accessed 22 April 2009
- 16.Jolliffe IT (2002) Principal component analysis. Springer Series in Statistics, 2nd edn. Springer, New YorkGoogle Scholar
- 17.Butzer JS, Butler APH, Butler PH, Bones PJ, Cook N, Tlustos L (2008) Medipix imaging: evaluation of datasets with PCA. Image Vis Comput NZ, 23rd Int Conf Proc p1–6 doi: 10.1109/IVCNZ.2008.4762080
- 18.OpenSceneGraph. Available via http://www.openscenegraph.org/
- 21.Barreto M, Schoenhagen P, Nair A, Amatangelo S, Milite M, Obuchowski NA, Lieber ML, Halliburton SS (2008) Potential of dual-energy computed tomography to characterize atherosclerotic plaque: ex vivo assessment of human coronary arteries in comparison to histology. J Cardiovasc Comput Tomogr 2:234–242CrossRefPubMedGoogle Scholar
- 24.Amendoliaa S, Bisognib M, Bottiglib U, Cioccib M, Delogub P, Dipasqualec G, Fantaccib M, Maestrob P, Marzullib V, Mikulecd B, Pernigottib E, Rossob V, Stefaninib A, Stumbob S (2001) Test of a GaAs-based pixel device for digital mammography. Nucl Instrum Methods Phys Res A 460:50–54CrossRefGoogle Scholar
- 29.Batchelar DL, Davidson MTM, Dabrowski W, Cunningham IA (2006) Bone composition imaging using coherent-scatter computed tomography. Assessing bone health beyond bone mineral density. Med Phys 33:904–915Google Scholar