A Monte Carlo investigation of artifacts caused by liver uptake in single-photon emission computed tomography perfusion imaging with technetium 99m-labeled agents

Background-Soft tissue attenuation is a prominent cause of single-photon emission computed tomography (SPECT) imaging artifacts, which may result in reduced diagnostic accuracy of myocardial perfusion imaging. A method incorporating simultaneously acquired transmission data permits nonuniform attenuation correction and when incorporating scatter correction and resolution compensation may substantially reduce interpretive errors. Methods and Results-A prospective multicenter trial was performed recruiting patients with angiographically documented coronary disease (nϭ96) and group of subjects with a low likelihood of disease (nϭ88). The uncorrected and attenuation/scatter corrected images were read independently, without knowledge of the patient's clinical data. The detection of Ն50% stenosis was similar using uncorrected perfusion data or with attenuation/ scatter correction and resolution compensation (visual or visual plus quantitative analysis), 76% versus 75% versus 78%, respectively (PϭNS). The normalcy rate, however, was significantly improved with this new methodology, using either the corrected images (86% vs 96%; Pϭ0.011) or with the corrected data and quantitative analysis (86% vs 97%; Pϭ0.007). The receiver operator characteristic curves were also found to be marginally but not significantly higher with attenuation/scatter correction than with tradition SPECT imaging. However, the ability to detect multivessel disease was reduced with attenuation/scatter correction. Regional differences were also noted, with reduced sensitivity but improved specificity for right coronary lesions using attenuation/scatter correction methodology. Conclusions-This multicenter trial demonstrates the initial clinical results of a new SPECT perfusion imaging modalityincorporating attenuation and scatter correction in conjunction with 99m Tc sestamibi perfusion imaging. Significant improvements in the normalcy rate were noted without a decline in overall sensitivity but with a reduction in detection of extensive coronary disease. (Circulation. 1999;99:2742-2749.)

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“…In fact, attenuation correction without scatter correction may even promote artifact production. 5,33 …”

Section: Current Trialmentioning

confidence: 99%

Multicenter Clinical Trial to Evaluate the Efficacy of Correction for Photon Attenuation and Scatter in SPECT Myocardial Perfusion Imaging

et al. 1999

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“…Several experiments have shown that all these degradations have to be corrected for to optimize clinical SPECT images (4)(5)(6)(7)(8)(9). The correction of attenuation and camera blurring is a relatively straightforward and well-established process.…”

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confidence: 99%

Evaluation of 3D Monte Carlo-Based Scatter Correction for 201Tl Cardiac Perfusion SPECT

Xiao¹,

Wit²,

Zbijewski³

et al. 2007

Journal of Nuclear Medicine

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201 Tl-Chloride ( 201 Tl) is a myocardial perfusion SPECT agent with excellent biochemical properties commonly used for assessing tissue viability. However, cardiac 201 Tl SPECT images are severely degraded by photons scattered in the thorax. Accurate correction for this scatter is complicated by the nonuniform density and varied sizes of thoraxes, by the additional attenuation and scatter caused by female patients' breasts, and by the energy spectrum of 201 Tl. Monte Carlo simulation is a general and accurate method well suited to modeling this scatter. Methods: Statistical reconstruction that includes Monte Carlo modeling of scatter was compared with statistical reconstruction algorithms not corrected for scatter. In the ADS method, corrections for attenuation, detector response, and scatter (Monte Carlo-based) were implemented simultaneously via the dual-matrix orderedsubset expectation maximization algorithm with a Monte Carlo simulator as part of the forward projector. The ADS method was compared with the A method (ordered-subset expectation maximization with attenuation correction) and with the AD method (a method like the A method but with detector response modeling added). A dual-head SPECT system equipped with two 153 Gd scanning line sources was used for simultaneously acquiring transmission and emission data. Four clinically realistic phantom configurations (a large thorax and a small thorax, each with and without breasts) with a cardiac insert containing 2 cold defects were used to evaluate the proposed reconstruction algorithms. We compared the performance of the different algorithms in terms of noise properties, contrast-to-noise ratios, the contrast separability of perfusion defects, uniformity, and robustness to anatomic variations. Results: The ADS method provided images with clearly better visual defect contrast than did the other methods. The contrasts achieved with the ADS method were 10%-24% higher than those achieved with the AD method and 11%-37% higher than those achieved with the A method. For a typical contrast level, the ADS method exhibited noise levels around 27% lower than the AD method and 34% lower than the A method. Compared with the other 2 algorithms, the ADS reconstructions were less sensitive to anatomic variations and had better image uniformity in the homogeneously perfused myocardium. Finally, we found that the improvements that can be achieved with Monte Carlo-based scatter correction are stronger for 201 Thal lium-201 chloride ( 201 Tl) is a perfusion agent commonly used for myocardial perfusion SPECT. In addition to assessment of myocardial perfusion in both stress and rest situations, the unique redistribution property has made 201 Tl SPECT an effective modality for identifying myocardial viability (1). However, because of the combined effects of some of the physical properties of 201 Tl, the quality of SPECT images obtained with this perfusion agent is often suboptimal. Compared with 99m Tc images, 201 Tl images are more degraded by attenuation and scatter because...

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“…Exercise promotes a redistribution of blood flow, shunting it to the skeletal musculature and away from intraabdominal organs such as the liver (27). inferior wall (9)(10)(11)(12). With respect to the influence on myocardial counts from hot liver activity, the artifactual decrease in inferior activity is worse seems to be greater in higher liver activity.…”

Section: Pharmacological Versus Exercise Stressmentioning

confidence: 99%

“…Compared to exercise stress, pharmacological stress has shown a high liver uptake of 99m Tc perfusion radiopharmaceuticals (7,8). Such high liver uptake may create artifactual defects in the inferior wall with filtered back-projection reconstruction (9)(10)(11)(12). We hypothesized that pharmacological and exercise stress may show different improvements in the inferior wall in a prone SPECT study.…”

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confidence: 99%

Differences in Perfusion between Pharmacological Stress and Exercise Stress on Prone Myocardial SPECT

Maeda

Kubo

Futaki

et al. 2016

Annals of Nuclear Cardiology

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Backgrounds: Myocardial single-photon emission computerized tomography (SPECT) with the patient in the prone position has recently been applied to improve the percentage uptake (%uptake) in the inferior wall by reducing diaphragmatic attenuation. We hypothesized that the type of stress might cause a difference in the %uptake improvement in inferior regions in the prone position. The purpose of this study was to compare the %uptake improvement between exercise and pharmacological vasodilator stress in prone myocardial SPECT.

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A Monte Carlo investigation of artifacts caused by liver uptake in single-photon emission computed tomography perfusion imaging with technetium 99m-labeled agents

Cited by 71 publications

References 12 publications

Multicenter Clinical Trial to Evaluate the Efficacy of Correction for Photon Attenuation and Scatter in SPECT Myocardial Perfusion Imaging

Multicenter Clinical Trial to Evaluate the Efficacy of Correction for Photon Attenuation and Scatter in SPECT Myocardial Perfusion Imaging

Evaluation of 3D Monte Carlo-Based Scatter Correction for 201Tl Cardiac Perfusion SPECT

Differences in Perfusion between Pharmacological Stress and Exercise Stress on Prone Myocardial SPECT

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