Anomaly Detection and Artifact Recovery in PET Attenuation-Correction Images Using the Likelihood Function

In dual modality PET/CT, CT data are used to generate the attenuation correction applied in the reconstruction of the PET emission image. This requires converting the CT image into a 511-keV attenuation map. Algorithms for making this transformation require assumptions about the makeup of material within the patient. Anomalous material such as contrast agent administered to enhance the CT scan confounds conversion algorithms and has been observed to result in inaccuracies, i.e. inconsistencies with the true 511-keV attenuation present at the time of the PET emission scan. These attenuation artifacts carry through to the final attenuation-corrected PET emission image and can resemble diseased tissue. We propose an approach to correcting this problem that employs the attenuation information carried by the PET emission data. A likelihood-based algorithm for identifying and correcting contrast artifacts is presented and tested. The algorithm exploits the fact that contrast artifacts manifest as too-high attenuation values in an otherwise high quality attenuation image. In a separate study, the performance of the loglikelihood as an objective-function component, independent of any particular algorithm, is mapped out for several imaging scenarios as a function of statistical noise. Both the full algorithm and the loglikelihood performed well in studies with simulated data. Additional studies including those with patient data are required to fully understand their capabilities .

[1]  Volker Dicken,et al.  A new approach towards simultaneous activity and attenuation reconstruction in emission tomography , 1999 .

[2]  B. H. Hasegawa,et al.  Investigation of the use of X-ray CT images for attenuation compensation in SPECT , 1994 .

[3]  P B Hoffer,et al.  Computerized three-dimensional segmented human anatomy. , 1994, Medical physics.

[4]  Chuanyong Bai,et al.  A generalized model for the conversion from CT numbers to linear attenuation coefficients , 2002, 2002 IEEE Nuclear Science Symposium Conference Record.

[5]  Paul Kinahan,et al.  A combined PET/CT scanner for clinical oncology. , 2000, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[6]  A. V. Bronnikov,et al.  Reconstruction of attenuation map using discrete consistency conditions , 2000, IEEE Transactions on Medical Imaging.

[7]  Charles M. Laymon,et al.  Calculation of attenuation factors from combined singles and coincidence emission projections , 1999, IEEE Transactions on Medical Imaging.

[8]  Thomas Beyer,et al.  The SMART scanner: a combined PET/CT tomograph for clinical oncology , 1998, 1998 IEEE Nuclear Science Symposium Conference Record. 1998 IEEE Nuclear Science Symposium and Medical Imaging Conference (Cat. No.98CH36255).

[9]  H. Malcolm Hudson,et al.  Accelerated image reconstruction using ordered subsets of projection data , 1994, IEEE Trans. Medical Imaging.

[10]  F. Natterer Computerized Tomography with Unknown Sources , 1983 .

[11]  Johan Nuyts,et al.  Reduction of the Influence of Intravenous Contrast in PET/CT by Using a Threshold Conversion Method , 2007, IEEE Transactions on Nuclear Science.

[12]  Gerald Antoch,et al.  Focal tracer uptake: a potential artifact in contrast-enhanced dual-modality PET/CT scans. , 2002, Journal of nuclear medicine : official publication, Society of Nuclear Medicine.

[13]  James E. Bowsher,et al.  An EM algorithm for estimating SPECT emission and transmission parameters from emission data only , 2001, IEEE Transactions on Medical Imaging.

[14]  Grant T. Gullberg,et al.  Toward accurate attenuation correction in SPECT without transmission measurements , 1997, IEEE Transactions on Medical Imaging.

[15]  P. Gantet,et al.  Attenuation correction using SPECT emission data only , 2001 .

[16]  Hakan Erdogan,et al.  Ordered subsets algorithms for transmission tomography. , 1999, Physics in medicine and biology.

[17]  Jeffrey A. Fessler,et al.  A penalized-likelihood image reconstruction method for emission tomography, compared to postsmoothed maximum-likelihood with matched spatial resolution , 2003, IEEE Transactions on Medical Imaging.

[18]  A. Lee Swindlehurst,et al.  IEEE Journal of Selected Topics in Signal Processing Inaugural Issue: [editor-in-chief's message] , 2007, J. Sel. Topics Signal Processing.

[19]  G Glatting,et al.  Simultaneous iterative reconstruction of emission and attenuation images in positron emission tomography from emission data only. , 2002, Medical physics.

[20]  S. H. Manglos,et al.  Constrained IntraSPECT reconstruction from SPECT projections , 1993, 1993 IEEE Conference Record Nuclear Science Symposium and Medical Imaging Conference.

[21]  Thomas Beyer,et al.  X-ray-based attenuation correction for positron emission tomography/computed tomography scanners. , 2003, Seminars in nuclear medicine.

[22]  Thomas K. Lewellen,et al.  The SimSET Program , 2012 .

[23]  A. Buck,et al.  PET attenuation coefficients from CT images: experimental evaluation of the transformation of CT into PET 511-keV attenuation coefficients , 2002, European Journal of Nuclear Medicine and Molecular Imaging.

[24]  A V Bronnikov,et al.  Numerical solution of the identification problem for the attenuated Radon transform , 1999 .

[25]  Habib Zaidi,et al.  Comparative Assessment of Energy-Mapping Approaches in CT-Based Attenuation Correction for PET , 2011, Molecular Imaging and Biology.

[26]  L. Shepp,et al.  Maximum Likelihood Reconstruction for Emission Tomography , 1983, IEEE Transactions on Medical Imaging.

[27]  Ken D. Sauer,et al.  A unified approach to statistical tomography using coordinate descent optimization , 1996, IEEE Trans. Image Process..

[28]  B. H. Hasegawa,et al.  Attenuation correction of SPECT using X-ray CT on an emission-transmission CT system: Myocardial perfusion assessment , 1995 .

[29]  J. Nuyts,et al.  Reduction of attenuation correction artifacts in PET-CT , 2005, IEEE Nuclear Science Symposium Conference Record, 2005.

[30]  Y. Censor,et al.  A New Approach to the Emission Computerized Tomography Problem: Simultaneous Calculation of Attenuation and Activity Coefficients , 1979, IEEE Transactions on Nuclear Science.

[31]  Rolf Clackdoyle,et al.  Attenuation correction in PET using consistency information , 1998 .

[32]  Ken D. Sauer,et al.  Parallelizable Bayesian tomography algorithms with rapid, guaranteed convergence , 2000, IEEE Trans. Image Process..

[33]  F. Crepaldi,et al.  Activity and Attenuation Reconstruction for Positron Emission Tomography Using Emission Data Only Via Maximum Likelihood and Iterative Data Refinement , 2007, IEEE Transactions on Nuclear Science.

[34]  Anand Rangarajan,et al.  An accelerated convergent ordered subsets algorithm for emission tomography , 2004, Physics in medicine and biology.

[35]  Hakan Erdogan,et al.  Monotonic algorithms for transmission tomography , 1999, IEEE Transactions on Medical Imaging.

[36]  Ken D. Sauer,et al.  A generalized Gaussian image model for edge-preserving MAP estimation , 1993, IEEE Trans. Image Process..

[37]  Paul Kinahan,et al.  Attenuation correction for a combined 3D PET/CT scanner. , 1998, Medical physics.

[38]  Patrick Dupont,et al.  Simultaneous maximum a posteriori reconstruction of attenuation and activity distributions from emission sinograms , 1999, IEEE Transactions on Medical Imaging.

[39]  J. H. Hubbell,et al.  XCOM: Photon Cross Section Database (version 1.2) , 1999 .

[40]  A. V. Bronnikov,et al.  Approximate reconstruction of attenuation map in SPECT imaging , 1995 .

[41]  Simon R. Cherry,et al.  Fast gradient-based methods for Bayesian reconstruction of transmission and emission PET images , 1994, IEEE Trans. Medical Imaging.