Derivation of attenuation map for attenuation correction of PET data in the presence of nanoparticulate contrast agents using spectral CT imaging.
OBJECTIVE
Uptake value in quantitative PET imaging is biased due to the presence of CT contrast agents when using CT-based attenuation correction. Our aim was to examine spectral CT imaging to suppress inaccuracy of 511 keV attenuation map in the presence of multiple nanoparticulate contrast agents.


METHODS
Using a simulation study we examined an image-based K-edge ratio method, in which two images acquired from energy windows located above and below the K-edge energy are divided by one another, to identify the exact location of all contrast agents. Multiple computerized phantom studies were conducted using a variety of NP contrast agents with different concentrations. The performance of the proposed methodology was compared to conventional single-kVp and dual-kVp methods using wide range of contrast agents with varying concentrations.


RESULTS
The results demonstrate that both single-kVp and dual-kVp energy mapping approaches produce inaccurate attenuation maps at 511 keV in the presence of multiple simultaneous contrast agents. In contrast, the proposed method is capable of handling multiple simultaneous contrast agents, thus allowing suppression of 511 keV attenuation map inaccuracy.


CONCLUSIONS
Attenuation map produced by spectral CT clearly outperforms conventional single-kVp and dual-kVp approaches in the generation of accurate attenuation maps in the presence of multiple contrast agents.
Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran.
Hossein
H
Ghadiri
Mohammad Bagher
MB
Shiran
Hamid
H
Soltanian-Zadeh
Arman
A
Rahmim
Habib
H
Zaidi
Mohammad Reza
MR
Ay
D003198:Computer Simulation; D003287:Contrast Media; D006801:Humans; D008954:Models, Biological; D053758:Nanoparticles; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000295:instrumentation / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*
D003287:Contrast Media