Partial volume effect correction in PET using regularized iterative deconvolution with variance control based on local topology Journal Article


Authors: Kirov, A. S.; Piao, J. Z.; Schmidtlein, C. R.
Article Title: Partial volume effect correction in PET using regularized iterative deconvolution with variance control based on local topology
Abstract: Correcting positron emission tomography (PET) images for the partial volume effect (PVE) due to the limited resolution of PET has been a long-standing challenge. Various approaches including incorporation of the system response function in the reconstruction have been previously tested. We present a post-reconstruction PVE correction based on iterative deconvolution using a 3D maximum likelihood expectation-maximization (MLEM) algorithm. To achieve convergence we used a one step late (OSL) regularization procedure based on the assumption of local monotonic behavior of the PET signal following Alenius et al. This technique was further modified to selectively control variance depending on the local topology of the PET image. No prior 'anatomic' information is needed in this approach. An estimate of the noise properties of the image is used instead. The procedure was tested for symmetric and isotropic deconvolution functions with Gaussian shape and full width at half-maximum (FWHM) ranging from 6.31 mm to infinity. The method was applied to simulated and experimental scans of the NEMA NU 2 image quality phantom with the GE Discovery LS PET/CT scanner. The phantom contained uniform activity spheres with diameters ranging from 1 cm to 3.7 cm within uniform background. The optimal sphere activity to variance ratio was obtained when the deconvolution function was replaced by a step function few voxels wide. In this case, the deconvolution method converged in ∼3-5 iterations for most points on both the simulated and experimental images. For the 1 cm diameter sphere, the contrast recovery improved from 12% to 36% in the simulated and from 21% to 55% in the experimental data. Recovery coefficients between 80% and 120% were obtained for all larger spheres, except for the 13 mm diameter sphere in the simulated scan (68%). No increase in variance was observed except for a few voxels neighboring strong activity gradients and inside the largest spheres. Testing the method for patient images increased the visibility of small lesions in non-uniform background and preserved the overall image quality. Regularized iterative deconvolution with variance control based on the local properties of the PET image and on estimated image noise is a promising approach for partial volume effect corrections in PET. © 2008 Institute of Physics and Engineering in Medicine.
Keywords: positron emission tomography; image analysis; lung neoplasms; analytic method; patient monitoring; validation study; simulation; algorithm; medical imaging; quantitative analysis; image quality; three dimensional imaging; positron-emission tomography; phantoms, imaging; image processing, computer-assisted; image processing; image reconstruction; monte carlo method; noise reduction; maximum likelihood method; convergence of numerical methods; maximum likelihood; iterative deconvolution; partial volume effects; deconvolution method; maximum likelihood expectation maximization algorithm; partial volume effect; reaction optimization
Journal Title: Physics in Medicine and Biology
Volume: 53
Issue: 10
ISSN: 0031-9155
Publisher: IOP Publishing Ltd  
Date Published: 2008-01-01
Start Page: 2577
End Page: 2591
Language: English
DOI: 10.1088/0031-9155/53/10/009
PUBMED: 18441414
PROVIDER: scopus
DOI/URL:
Notes: --- - "Cited By (since 1996): 13" - "Export Date: 17 November 2011" - "CODEN: PHMBA" - "Source: Scopus"
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  1. Assen Kirov
    89 Kirov