Influence of acquisition orbit on phase analysis of gated single photon emission computed tomography myocardial perfusion imaging for assessment of left ventricular mechanical dyssynchrony

Misaka, Tomofumi; Hosono, Makoto; Kudo, Takashi; Ito, Takamichi; Syomura, T.; Uemura, Masanobu; Okajima, Kaoru

doi:10.1007/s12149-017-1151-x

Cited by 6 publications

(3 citation statements)

References 30 publications

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“…In addition, reconstructions of projections from a 180‐degree acquisition converge more slowly and to lower activity concentration values than reconstructions of a 360‐degree acquisition. In cardiac imaging, it was shown that a 180‐degree arc was related to inhomogeneities and quantitation errors . This is in line with our results, showing no significant difference in image quality and dosimetric accuracy in images obtained with the HCS protocol compared with images obtained with the uniform projection‐time protocol.…”

Section: Discussionsupporting

confidence: 91%

Fast technetium‐99m liver SPECT for evaluation of the pretreatment procedure for radioembolization dosimetry

et al. 2018

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Purpose: The efficiency of radioembolization procedures could be greatly enhanced if results of the 99m Tc-MAA pretreatment procedure were immediately available in the interventional suite, enabling 1-day procedures as a result of direct estimation of the hepatic radiation dose and lung shunt fraction. This would, however, require a relatively fast, but still quantitative, SPECT procedure, which might be achieved with acquisition protocols using nonuniform durations of the projection images. Methods: SPECT liver images of the 150-MBq 99m Tc-MAA pretreatment procedure were simulated for eight different lesion locations and two different lesion sizes using the digital XCAT phantom for both single-and dual-head scanning geometries with respective total acquisition times of 1, 2, 5, 10, and 30 min. Three nonuniform projection-time acquisition protocols ("half-circle SPECT (HCS)," "nonuniform SPECT (NUS) I," and "NUS II") for fast quantitative SPECT of the liver were designed and compared with the standard uniform projection-time protocol. Images were evaluated in terms of contrast-tonoise ratio (CNR), activity recovery coefficient (ARC), tumor/non-tumor (T/N) activity concentration ratio, and lung shunt fraction (LSF) estimation. In addition, image quality was verified with a physical phantom experiment, reconstructed with both clinical and Monte Carlo-based reconstruction software. Results: Simulations showed no substantial change in image quality and dosimetry by usage of a nonuniform projection-time acquisition protocol. Upon shortening acquisition times, CNR dropped, but ARC, T/N ratio, and LSF estimates were stable across all simulated acquisition times. Results of the physical phantom were in agreement with those of the simulations. Conclusion: Both uniform and nonuniform projection-time acquisition liver SPECT protocols yield accurate dosimetric metrics for radioembolization treatment planning in the interventional suite within 10 min, without compromising image quality. Consequently, fast quantitative SPECT of the liver in the interventional suite is feasible.

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Section: Discussionsupporting

confidence: 91%

Fast technetium‐99m liver SPECT for evaluation of the pretreatment procedure for radioembolization dosimetry

et al. 2018

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“…In addition, the value of phase analysis may vary depending on the software program, even when using the same software (22,23). Additionally, the phase parameter has great variability because the phase histogram is affected by many factors, such as sex, cardiovascular risk factors, including hypertension, diabetes, and kidney disease, and imaging protocol (7,24,25).…”

Section: Discussionmentioning

confidence: 99%

The feasibility of 18F-FDG gated positron emission tomography (PET) for left ventricular dyssynchrony assessment in comparison with 99mTc-MIBI gated single-photon emission computed tomography (SPECT) among patients with prior myocardial infarction

Yao¹,

Wei²,

Wang³

2022

Quant Imaging Med Surg

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Background: Phase analysis by 99m Tc-MIBI gated single-photon emission computed tomography (GSPECT) has been considered to be an adequate method in the validation of left ventricular (LV) dyssynchrony. Compared with GSPECT, prior myocardial infarction patients with myocardial perfusion defects but myocardial viability usually show preserved uptake of 18 F-FDG, and extensive myocardium is detected by 18 F-FDG gated positron emission tomography (GPET). Thus, theoretically, it should be more accurate. The aim of this study was to investigate the feasibility of GPET for LV dyssynchrony assessment in comparison with GSPECT among infarction patients.Methods: A total of 146 patients with infarction underwent 2 consecutive days of GSPECT and GPET examinations. Quantitative gated SPECT-derived LV phase analysis was applied to GPET and GSPECT data to assess the presence of LV dyssynchrony via histogram bandwidth (BW) and phase standard deviation (SD). The correlation and agreement of BW and SD between GSPECT and GPET were examined. Factors (i.e., total perfusion defect, scar and mismatch) related to the discrepancies of LV dyssynchrony (i.e., BW and SD) in GPET and GSPECT were assessed by univariate and multivariate regression analysis.Results: A moderate correlation between GPET and GSPECT was found in the measurements of BW (r=0.554) and SD (r=0.537). Bland-Altman analysis revealed that GPET overestimated both BW and SD (20.5° and 9.5°, respectively). In addition, the BW and SD measured by GPET were still overestimated after subgroup analysis. Between GPET and GSPECT, multivariate regression analysis revealed that total perfusion defects were related to the difference in BW measurement (P<0.001), and mismatch was associated with the difference in SD measurement (P<0.01). Conclusions:In patients with infarction, GPET moderately correlated with GSPECT in assessing LV dyssynchrony. GPET overestimated both BW and SD, so these analyses should not be interchangeable in individual patients.

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“…Acquisition orbits of 180°a nd 360°significantly influenced bandwidth and phase SD in a clinical study. 6 Notably, sex influences phase parameters. 7 When male and female LV end-diastolic volumes were matched in a normal database, entropy was significantly higher in males than in females (26.3% ± 8.0% vs 20.1% ± 5.5%, p = 0.020).…”

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confidence: 99%

What does entropy reveal in phase analysis of myocardial perfusion SPECT?

Okuda

Nakajima

2021

Journal of Nuclear Cardiology

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others expanded the concept into statistical mechanics. Claude Elwood Shannon also introduced a new aspect of entropy into information theory during 1948. 1 Consequently, the long, notable history of entropy studies has facilitated understanding of the laws of nature. Among several equations for entropy that are applied across many scientific disciplines, the Shannon equation (H ¼ À P p i log p i , where p i is the probability of state i) that is based on information theory is applied to phase analyses of gated single-photon emission computed tomography (SPECT). In phase histograms generated from gated SPECT data, p i represents the frequency of the histogram bin i. Entropy increases if the phase distribution becomes disordered in histograms. If the equation for entropy is divided by log (n), in which n represents the number of histogram bins, the entropy range is 0-1, which represents total order to disorder.A study by Shimizu and colleagues published in this issue of the Journal of Nuclear Cardiology showed that entropy and estimated glomerular filtration rates (eGFR) could predict a poor cardiac prognosis in patients with complete left bundle branch block (CLBBB). 2 High entropy and low eGFR were independent predictors determined by Cox regression and Kaplan-Meyer analyses for major cardiac events (MACE) in these patients. Moreover, Random Forest machine learning also clarified entropy and eGFR as independent predictors of MACE. Others have used left ventricular (LV) volumes, LV ejection fraction, echocardiographic parameters, and clinical demographics as predictors of heart disease. Although entropy might be able to clarify the pathophysiology of patients with CLBBB, whether it implies causative indices and provides clinical information that is directly related to pathophysiology cannot be determined. This is because physical aspects of acquisition and processing along with patient-associated factors can influence entropy, which is also susceptible to LV volume, LV ejection fraction, age, statistical noise, and heart failure. 3 Since the phase distribution derived from gated SPECT images can easily be influenced by acquisition conditions and patient characteristics, entropy includes many kinds of artifacts in addition to bandwidth and phase standard deviation (SD). Previous studies have shown that the amount of time required to acquire SPECT images (acquisition time) considerably influences phase analysis. Decreasing acquisition time is associated with increased entropy in clinical patients. 4 Reducing the amount of acquisition time by 50% changed mean entropy from 55.0% ± 6.41% to 59.5% ± 6.06% (p \ 0.002). Moreover, decreased gated SPECT counts were also associated with increased entropy in a phantom study. 5 A decrease in the average SPECT count per pixel from 97.7 to 17.8 increased entropy from 0.26 to 0.35. Acquisition orbits of 180°a nd 360°significantly influenced bandwidth and phase SD in a clinical study. 6 Notably, sex influences phase parameters. 7 When male and female LV end-diastolic volumes were...

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Influence of acquisition orbit on phase analysis of gated single photon emission computed tomography myocardial perfusion imaging for assessment of left ventricular mechanical dyssynchrony

Abstract: Differences in acquisition orbit had a significant influence on HBW and PSD with Tl-gated SPECT MPI in the inferior wall in patients with major hypoperfusion myocardium.

Cited by 6 publications

References 30 publications

Fast technetium‐99m liver SPECT for evaluation of the pretreatment procedure for radioembolization dosimetry

Fast technetium‐99m liver SPECT for evaluation of the pretreatment procedure for radioembolization dosimetry

The feasibility of 18F-FDG gated positron emission tomography (PET) for left ventricular dyssynchrony assessment in comparison with 99mTc-MIBI gated single-photon emission computed tomography (SPECT) among patients with prior myocardial infarction

What does entropy reveal in phase analysis of myocardial perfusion SPECT?

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