Attenuation Correction Strategies for Positron Emission Tomography/Computed Tomography and 4-Dimensional Positron Emission Tomography/Computed Tomography

Pan, Tinsu; Zaidi, Habib

doi:10.1016/j.cpet.2012.09.009

Cited by 8 publications

(7 citation statements)

References 74 publications

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“…In fact, to the best of our knowledge, no studies have reported on the use of gating in dynamic PET MPI. Furthermore, besides blurring, motion may cause misregistrations between the PET emission data and the attenuation map, especially with sequential PET-CT. Emission/attenuation maps misalignments may cause confounding image artifacts as well as quantitation biases in the reconstructed PET activity distributions (Loghin et al ., 2004; Gould et al ., 2007; Pan and Zaidi, 2013). Finally, the PVE, which results from the scanner’s finite point spread function (PSF), further reduce image resolution, signal-to-noise-ratio (SNR) and quantitative accuracy.…”

Section: Introductionmentioning

confidence: 99%

Impact of motion and partial volume effects correction on PET myocardial perfusion imaging using simultaneous PET-MR

et al. 2016

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PET is an established modality for myocardial perfusion imaging (MPI) which enables quantification of absolute myocardial blood flow (MBF) using dynamic imaging and kinetic modeling. However, heart motion and Partial Volume Effects (PVE) significantly limit the spatial resolution and quantitative accuracy of PET MPI. Simultaneous PET-MR offers a solution to the motion problem in PET by enabling MR-based motion correction of PET data. The aim of this study was to develop a motion and PVE correction methodology for PET MPI using simultaneous PET-MR, and to assess its impact on both static and dynamic PET MPI using 18F-Flurpiridaz, a novel 18F-labeled perfusion tracer. Two dynamic 18F-Flurpiridaz MPI scans were performed on healthy pigs using a PET-MR scanner. Cardiac motion was tracked using a dedicated tagged-MRI (tMR) sequence. Motion fields were estimated using non-rigid registration of tMR images and used to calculate motion-dependent attenuation maps. Motion correction of PET data was achieved by incorporating tMR-based motion fields and motion-dependent attenuation coefficients into image reconstruction. Dynamic and static PET datasets were created for each scan. Each dataset was reconstructed as (i) Ungated, (ii) Gated (end-diastolic phase), and (iii) Motion-Corrected (MoCo), each without and with point spread function (PSF) modeling for PVE correction. Myocardium-to-blood concentration ratios (MBR) and apparent wall thickness were calculated to assess image quality for static MPI. For dynamic MPI, segment- and voxel-wise myocardial blood flow (MBF) values were estimated by non-linear fitting of a 2-tissue compartment model to tissue time-activity-curves. MoCo and Gating respectively decreased mean apparent wall thickness by 15.1% and 14.4% and increased MBR by 20.3% and 13.6% compared to Ungated images (P<0.01). Combined motion and PSF correction (MoCo-PSF) yielded 30.9% (15.7%) lower wall thickness and 82.2% (20.5%) higher MBR compared to Ungated data reconstructed without (with) PSF modeling (P<0.01). For dynamic PET, mean MBF across all segments were comparable for MoCo (0.72±0.21 mL/min/mL) and Gating (0.69±0.18 mL/min/mL). Ungated data yielded significantly lower mean MBF (0.59±0.16 mL/min/mL). Mean MBF for MoCo-PSF was 0.80±0.22 mL/min/mL, which was 37.9% (25.0%) higher than that obtained from Ungated data without (with) PSF correction (P<0.01). The developed methodology holds promise to improve the image quality and sensitivity of PET MPI studies performed using PET-MR.

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Section: Introductionmentioning

confidence: 99%

Impact of motion and partial volume effects correction on PET myocardial perfusion imaging using simultaneous PET-MR

et al. 2016

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“…As illustrated in Fig. 1, the mean number of such detected scattered events P ab (θ) can be calculated by (1) where d KN C /d is the Klein-Nishina electronic cross-section and e (S) is the electron density at point S. f s represents the photon flux that reaches one of the possible scattered positions Q 978-1-4799-0534-8/13/$31.00 ©2013 IEEE S, calculated by integrating the source activity from A to S. Tau (τ) is the acquisition time and μ is the linear attenuation coefficient.…”

Section: Methodsmentioning

confidence: 99%

“…uantitatively accurate and artifact-free positron emission tomography (PET) images require compensation both for scatter and attenuation [1]. In contrary to the conventional scatter correction based approaches, we have proposed a generalized scatter (GS) reconstruction algorithm which uses both true and scattered coincidences in a self-consistent way to obtain the activity distribution [2].…”

Section: Introductionmentioning

confidence: 99%

Attenuation correction for a generalized scatter reconstruction in PET

Sun

Pisotrius

2013

2013 IEEE Nuclear Science Symposium and Medical Imaging Conference (2013 NSS/MIC)

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We have proposed a generalized scatter (GS) positron emission tomography (PET) reconstruction algorithm which can extract the activity distribution by using both true and scattered coincidences in a consistent way. However the conventional strategies for attenuation correction are no longer applicable for scattered photons. The goal of this study is to develop a method to address the photon attenuation correction for scattered coincidences.

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“…However, the acquisition of multiple CT images for respiratory-gating leads to a substantially increased radiation dose to patient [9]. Since the additional radiation dose of extended duration CT-based attenuation map acquisitions is considered unacceptable in clinical practice, several suboptimal approaches were proposed using single-phase CT scan at end-expiration or averaged CT images over one respiratory cycle in cine or low-pitch helical scan modes [10–13]. …”

Section: Introductionmentioning

confidence: 99%

Direct Reconstruction of CT-Based Attenuation Correction Images for PET With Cluster-Based Penalties

Kim

Alessio

Man

et al. 2017

IEEE Trans. Nucl. Sci.

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Extremely low-dose CT acquisitions used for PET attenuation correction have high levels of noise and potential bias artifacts due to photon starvation. This work explores the use of a priori knowledge for iterative image reconstruction of the CT-based attenuation map. We investigate a maximum a posteriori framework with cluster-based multinomial penalty for direct iterative coordinate decent (dICD) reconstruction of the PET attenuation map. The objective function for direct iterative attenuation map reconstruction used a Poisson log-likelihood data fit term and evaluated two image penalty terms of spatial and mixture distributions. The spatial regularization is based on a quadratic penalty. For the mixture penalty, we assumed that the attenuation map may consist of four material clusters: air+background, lung, soft tissue, and bone. Using simulated noisy sinogram data, dICD reconstruction was performed with different strengths of the spatial and mixture penalties. The combined spatial and mixture penalties reduced the RMSE by roughly 2 times compared to a weighted least square and filtered backprojection reconstruction of CT images. The combined spatial and mixture penalties resulted in only slightly lower RMSE compared to a spatial quadratic penalty alone. For direct PET attenuation map reconstruction from ultra-low dose CT acquisitions, the combination of spatial and mixture penalties offers regularization of both variance and bias and is a potential method to reconstruct attenuation maps with negligible patient dose. The presented results, using a best-case histogram suggest that the mixture penalty does not offer a substantive benefit over conventional quadratic regularization and diminishes enthusiasm for exploring future application of the mixture penalty.

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Attenuation Correction Strategies for Positron Emission Tomography/Computed Tomography and 4-Dimensional Positron Emission Tomography/Computed Tomography

Cited by 8 publications

References 74 publications

Impact of motion and partial volume effects correction on PET myocardial perfusion imaging using simultaneous PET-MR

Impact of motion and partial volume effects correction on PET myocardial perfusion imaging using simultaneous PET-MR

Attenuation correction for a generalized scatter reconstruction in PET

Direct Reconstruction of CT-Based Attenuation Correction Images for PET With Cluster-Based Penalties

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