Robustness of anatomically guided pixel-by-pixel algorithms for partial volume effect correction in positron emission tomography.

Service Hospitalier Frédéric Joliot, CEA, Orsay, France.
Journal of Cerebral Blood Flow & Metabolism (Impact Factor: 5.34). 06/1999; 19(5):547-59. DOI: 10.1097/00004647-199905000-00009
Source: PubMed

ABSTRACT Several algorithms have been proposed to improve positron emission tomography quantification by combining anatomical and functional information in a pixel-by-pixel correction scheme. The precision of these methods when applied to real data depends on the precision of the manifold correction steps, such as full-width half-maximum modeling, magnetic resonance imaging-positron emission tomography registration, tissue segmentation, or background activity estimation. A good understanding of the influence of these parameters thus is critical to the effective use of the algorithms. In the current article, the authors present a monodimensional model that allows a simple theoretical and experimental evaluation of correction imprecision. The authors then assess correction robustness in three dimensions with computer simulations, and evaluate the validity of regional SD as a correction performance criterion.

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    ABSTRACT: Summary Aim: We assess the influenc eo ft he reconstruction algo - rithm s( OS-EM for th ei terative on ev s. af iltered back-pro- jection in Fourie rs pace (DiFT)) on partial volume correction in PE Te mployin gaf ully 3D 3-compartment MR based PV- correction algorithm. Th eg ray matter voxel si nt he PE T imag e- afte rr emoval of the whit em atter an dc erebrospi- na lf luid contribution -a re corrected voxel-by-voxel usin g the imag er esolution . Material, methods: Phantom measurements an do ne healthy human brain FD Gs tudy were carrie do ut .F or the OSEM reconstruction ,ac om- bination of iteration step sa nd subset numbers (It/Sub )w as used, whereb yi nc ase of no-convergenc et he imag er esol- ution ha dt ob ef itted. The result s from the DiF Tr econstruc- tion wer ee quivalent to those obtaine df rom the OSEM re - construction with 10/32 combination fo ro bject sw it hw ide - spread activity concentration .F or the sphere phantom, the mean recovery based on the actual value sa chieve d9 9.2% ±1 .8 fo ra ll spheres an da ll reconstruction mode sa nd It / sub combinations (except fo r2 /8) .I nc ase of th eH offman 3D brain phantom th em ea nr ecovery of the cortica lr egion s wa s1 01% ±1 .2 (the increas eb ase do nt he uncorrected values: 35.5% ±1 .5), while the subcortical region s reached am ea nr ecovery of 80% with an increase of 43.9 %±2 .5. For the human data, an increas eo ft he metabolize dv alue so fs everal cortical region sr ange db e- tween 42% an d4 8% independent from the reconstruction mode . Conclusions: Ou rd ata show that th e3 -compart - ment fully 3- DM Rb ase dP V-correction is sensitive to the choice of reconstruction algorithms an dt ot he parameter choice. They indicat et ha td espite improved spatial resol- ution ,t he use of the iterative reconstruction algorith mf or PV-correction result si ns imilar recovery factors when com- pared to ac orrection usin gD iF Tr econstruction ,i nsofar the imag er esolution value sa re fitted at th eI t/Sub com- binations.
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    ABSTRACT: The ability to correctly quantify activity concentration with single photon emission computed tomography (SPECT) is limited by its spatial resolution. Blurring of data between adjacent structures, which is known as partial volume effects, can be compensated for by utilizing high resolution structural information from other imaging modalities such as CT or MRI. Previously developed partial volume correction (PVC) methods normally assume a spatially invariant point spread function. In SPECT this is not a good approximation, since the resolution varies with the distance from the collimator. A new method, p-PVC, was developed in this paper, which takes into account the distance dependent blurring. The method operates in projection space and is combined with filtered back-projection (FBP) reconstruction. Results from simulations show that similar quantitative results could be obtained with p-PVC+FBP as with OSEM with resolution recovery, although with better structural definition and an order of magnitude faster.
    Tsinghua Science & Technology 02/2010; 15(1):50-55.
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    ABSTRACT: We have developed, optimized, and validated a method for partial volume effect (PVE) correction of oncological lesions in positron emission tomography (PET) clinical studies, based on recovery coefficients (RC) and on PET measurements of lesion-to-background ratio (L/B m ) and of lesion metabolic volume. An operator-independent technique, based on an optimised threshold of the maximum lesion uptake, allows to define an isocontour around the lesion on PET images in order to measure both lesion radioactivity uptake and lesion metabolic volume. RC are experimentally derived from PET measurements of hot spheres in hot background, miming oncological lesions. RC were obtained as a function of PET measured sphere-to-background ratio and PET measured sphere metabolic volume, both resulting from the threshold-isocontour technique. PVE correction of lesions of a diameter ranging from 10 mm to 40 mm and for measured L/B m from 2 to 30 was performed using measured RC curves tailored at answering the need to quantify a large variety of real oncological lesions by means of PET. Validation of the PVE correction method resulted to be accurate (>89%) in clinical realistic conditions for lesion diameter > 1 cm, recovering >76% of radioactivity for lesion diameter < 1 cm. Results from patient studies showed that the proposed PVE correction method is suitable and feasible and has an impact on a clinical environment.
    BioMed research international. 01/2013; 2013:780458.

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