Jochen Cammin PhD, Presenter: Nothing to Disclose

Somesh Srivastava PhD, Abstract Co-Author: Employee, General Electric Company

George S. K. Fung PhD, Abstract Co-Author: Research support, Siemens AG

Katsuyuki Taguchi PhD, Abstract Co-Author: Research Grant, Siemens AG

To compare the detectability of vulnerable coronary plaque using photon-counting detectors with and without compensation for spectral distortions versus conventional energy integrating detectors.

Simulation studies for the detectability of atherosclerotic plaque were performed using a realistic computer phantom, a photon-counting detector with a realistic, non-ideal detector spectral response (resulting in spectral distortions) and noise, and a reconstruction technique that compensated for the distorted spectrum. The XCAT phantom with iodine-enhanced blood was modified to include coronary plaque, which consisted of a calcium deposit and vulnerable atherosclerotic plaque with or without Bismuth (Bi) nanoparticle enhanced surfaces. For each configuration two sets of projection data were generated: one for a photon-counting detector (PCD) with realistic spectral distortions, and the other for an energy-integrating detector (EID). Images of the plaque region were reconstructed from EID data using standard FBP and from PCD data with and without a sinogram-domain approach that compensated for the spectral distortions. Plaque detection was performed based on pixel values in ROIs in the plaque region and surrounding tissue from which ROC curves were obtained. The area under the ROC curve (AUC) was calculated as the performance index.

The AUC for vulnerable plaque without Bi nanoparticles was 0.986 for the PCD with compensation for spectral distortions, 0.833 for the PCD without compensation for spectral distortions, and 0.628 for the EID. The AUC for vulnerable plaque with Bi nanoparticles for the PCD was 0.996 with compensation for spectral distortions, 0.980 without compensation, and 0.541 for the EID. The latter value for EID indicated that there was almost no discrimination power.

The ability to detect vulnerable coronary plaque was consistently better for the PCD compared to the EID. Compensation of spectral distortions in PCDs improved the detectability further.

Photon-counting detectors enhance the detection performance of clinical CT systems for vulnerable atherosclerotic plaque and allow to differentiate between plaque types.

Cammin, J, Srivastava, S, Fung, G, Taguchi, K, Vulnerable Coronary Plaque Detection with Photon-counting X-ray CT Including Compensation for Spectral Distortions.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12027494.html