Loïc Boussel, Presenter: Nothing to Disclose

Philippe Coulon, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

Axel Thran, Abstract Co-Author: Nothing to Disclose

Ewald Roessl PhD, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV, Hamburg, Germany

Friedericke Schmidt, Abstract Co-Author: Employee, Koninklijke Philips Electronics NV

Roland Proksa, Abstract Co-Author: Researcher, Koninklijke Philips Electronics NV

Antoine Millon, Abstract Co-Author: Nothing to Disclose

Jean-Yves Scoazec, Abstract Co-Author: Nothing to Disclose

Nabil Hlaihel, Abstract Co-Author: Nothing to Disclose

Philippe Charles Douek MD, PhD, Abstract Co-Author: Nothing to Disclose

Mono- and dual- energy computed tomography (CT) scanner failed to accurately identify atheromatous plaque components because of their lack of spatial and energy resolution. We evaluated the capabilities of a Photon Counting Multi-Energy CT scanner to differentiate between the different components of coronary artery atherosclerotic plaque using their spectral attenuations and contrast agent maps.

8 calcified and 10 lipid-rich non-calcified histologically demonstrated atheromatous plaques from postmortem human coronary arteries filled and immerged into a 97 mmol/l Iodine solution were scanned with a Photon Counting Multi-Energy CT (Philips Research Europe-Hamburg) with the following parameters: 70 kVp, 20 mAs; FOV: 60 mm; resolution: 0.1x0.1x0.2mm. After crossing the sample, each individual photon was counted and classified according to its energy in 6 energy bins from 25 to 70 keV. Based on a maximum likelihood approach, the energy resolved projection data were decomposed to line integrals corresponding to the amount of photoelectric absorption (PA), compton scattering (CA) and iodine on each x-ray path. Image reconstruction of these data then lead to corresponding maps quantifying both x-ray absorption processes and the iodine concentration (IC) in the image plane. Measurements were performed on each map in vessel wall,  surrounding perivascular fat, lipid-rich and calcified plaques. PA and CA values are expressed relative to pure water values. Comparison between these different elements was performed using Mann Whitney tests with a Bonferroni correction.  

Results for vessel wall, surrounding perivascular fat, lipid-rich and calcified plaques were respectively 1.04+/-0.09, 0.54+/-0.11, 18.43+/-1.53, 0.86+/-0.13 for PA; 1.00+/-0.04, 0.91+/-0.02, 1.91+/-0.09, 0.99+/-0.14 for CA and 67.1+/-13.3, 32.4+/-10.3, 0, 47.7+/-12.6 mmol/l for IC, leading to a significant difference between all tissues for PA and IC (p<0.008) whereas for CA no significant difference was found between vessel wall, perivascular fat and lipid-rich plaques, as expected in this range of energy.

Photon Counting Multi-energy CT is a promising technique to identify plaque components by analyzing differences in contrast agent concentration and/or photoelectric attenuation.

Photon Counting Multi-energy CT is a promising technique to identify coronary artery atherosclerotic plaque components.

Boussel, L, Coulon, P, Thran, A, Roessl, E, Schmidt, F, Proksa, R, Millon, A, Scoazec, J, Hlaihel, N, Douek, P, Coronary Artery Atherosclerotic Plaque Components Analysis with Photon Counting Spectral CT.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9010331.html