Imaging Intramyocardial Microcirculatory Function Using Fast Computed Tomography

Möhlenkamp, Stefan; Schmermund, Axel; Kantor, Birgit; Erbel, Raimund; Ritman, Erik L.

doi:10.1385/1-59259-818-8:195

Cited by 3 publications

(2 citation statements)

References 104 publications

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“…In the dog study, all PVC methods led to reduced IMBV for this high count data, indicating the effectiveness of PVC to correct for the overestimation effect. Although no gold standard approach was applied to determine IMBV in the current study, previous studies (Möhlenkamp et al 2005, Vogel et al 2005 suggested that the typical IMBV for normal dogs was in the range between 10%-20%, which was consistent with our results after PVC. In future studies, we will validate in vivo IMBV quantified by the SPECT/CT approach against ex vivo myocardium specimens imaging using ultra-high resolution microCT as the gold standard of IMBV (Malyar et al 2004).…”

Section: Discussionsupporting

confidence: 91%

Anatomical-based partial volume correction for low-dose dedicated cardiac SPECT/CT

Liu

Chan

Grobshtein³

et al. 2015

Phys. Med. Biol.

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Due to the limited spatial resolution, partial volume effect (PVE) has been a major degrading factor on quantitative accuracy in emission tomography systems. This study aims to investigate the performance of several anatomical-based partial volume correction (PVC) methods for a dedicated cardiac SPECT/CT system (GE Discovery NM/CT 570c) with focused field-of-view (FOV) over a clinically relevant range of high and low count levels for two different radiotracer distributions. These PVC methods include perturbation Geometry Transfer Matrix (pGTM), pGTM followed by multi-target correction (MTC), pGTM with known concentration in blood pool, the former followed by MTC and our newly proposed methods, which perform the MTC method iteratively, where the mean values in all regions are estimated and updated by the MTC-corrected images each time in the iterative process. The NCAT phantom was simulated for cardiovascular imaging with 99mTc-tetrofosmin, a myocardial perfusion agent, and 99mTc-red blood cell (RBC), a pure intravascular imaging agent. Images were acquired at six different count levels to investigate the performance of PVC methods in both high and low count levels for low-dose applications. We performed two large animal in vivo cardiac imaging experiments following injection of 99mTc-RBC for evaluation of intramyocardial blood volume (IMBV). The simulation results showed our proposed iterative methods provide superior performance than other existing PVC methods in terms of image quality, quantitative accuracy, and reproducibility (standard deviation), particularly for low-count data. The iterative approaches are robust for both 99mTc-tetrofosmin perfusion imaging and 99mTc-RBC imaging of IMBV and blood pool activity even at low count levels. The animal study results indicated the effectiveness of PVC to correct the overestimation of IMBV due to blood pool contamination. In conclusion, the iterative PVC methods can achieve more accurate quantification, particularly for low count cardiac SPECT studies, typically obtained from low-dose protocols, gated studies, and dynamic applications.

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Section: Discussionsupporting

confidence: 91%

Anatomical-based partial volume correction for low-dose dedicated cardiac SPECT/CT

Liu

Chan

Grobshtein³

et al. 2015

Phys. Med. Biol.

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“…For the IMBV measurement, all the PVC methods yielded a reasonable estimation of IMBV except for the MTC approach with low count data. Although no gold standard approach was applied to determine IMBV in the current study, previous studies 44,45 suggest that the typical IMBV for normal dogs is in the range between 15% and 20%, which is consistent with our results after PVC. We will validate the IMBV measurement against the analysis of ex vivo myocardium specimens imaging using ultrahigh resolution microCT as the gold standard of IMBV in the future study.…”

Section: B Animal Studysupporting

confidence: 91%

Noise suppressed partial volume correction for cardiac SPECT/CT

Chan

Liu

Grobshtein³

et al. 2016

Medical Physics

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Purpose: Partial volume correction (PVC) methods typically improve quantification at the expense of increased image noise and reduced reproducibility. In this study, the authors developed a novel voxel-based PVC method that incorporates anatomical knowledge to improve quantification while suppressing noise for cardiac SPECT/CT imaging. Methods: In the proposed method, the SPECT images were first reconstructed using anatomicalbased maximum a posteriori (AMAP) with Bowsher's prior to penalize noise while preserving boundaries. A sequential voxel-by-voxel PVC approach (Yang's method) was then applied on the AMAP reconstruction using a template response. This template response was obtained by forward projecting a template derived from a contrast-enhanced CT image, and then reconstructed using AMAP to model the partial volume effects (PVEs) introduced by both the system resolution and the smoothing applied during reconstruction. To evaluate the proposed noise suppressed PVC (NS-PVC), the authors first simulated two types of cardiac SPECT studies: a 99m Tc-tetrofosmin myocardial perfusion scan and a 99m Tc-labeled red blood cell (RBC) scan on a dedicated cardiac multiple pinhole SPECT/CT at both high and low count levels. The authors then applied the proposed method on a canine equilibrium blood pool study following injection with 99m Tc-RBCs at different count levels by rebinning the list-mode data into shorter acquisitions. The proposed method was compared to MLEM reconstruction without PVC, two conventional PVC methods, including Yang's method and multitarget correction (MTC) applied on the MLEM reconstruction, and AMAP reconstruction without PVC. Results: The results showed that the Yang's method improved quantification, however, yielded increased noise and reduced reproducibility in the regions with higher activity. MTC corrected for PVE on high count data with amplified noise, although yielded the worst performance among all the methods tested on low-count data. AMAP effectively suppressed noise and reduced the spill-in effect in the low activity regions. However it was unable to reduce the spill-out effect in high activity regions. NS-PVC yielded superior performance in terms of both quantitative assessment and visual image quality while improving reproducibility. Conclusions:The results suggest that NS-PVC may be a promising PVC algorithm for application in low-dose protocols, and in gated and dynamic cardiac studies with low counts. C 2016 American Association of Physicists in Medicine. [http://dx

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Cardiac computed tomography imaging: a history and some future possibilities

Ritman

2003

Cardiology Clinics

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Imaging Intramyocardial Microcirculatory Function Using Fast Computed Tomography

Cited by 3 publications

References 104 publications

Anatomical-based partial volume correction for low-dose dedicated cardiac SPECT/CT

Anatomical-based partial volume correction for low-dose dedicated cardiac SPECT/CT

Noise suppressed partial volume correction for cardiac SPECT/CT

Cardiac computed tomography imaging: a history and some future possibilities

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