The increasing role of quantification in clinical nuclear cardiology: The Emory approach

Garcia, Ernest; Faber, Tracy L.; Cooke, C. David; Folks, Russell; Chen, Ji; Santana, Cesar A.

doi:10.1016/j.nuclcard.2007.06.009

Cited by 183 publications

(120 citation statements)

References 17 publications

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“…34 The authors tested two image reconstruction softwares in CZT SPECT MPI to determine LV mass. They report that ECTb 35 somewhat overestimates LV mass at lower values and underestimates it at higher values, with more stable results obtained with Corridor-4DM. 36 This is likely due to the approach used in ECTb of 'fitting' gated cardiac results into a standardized 1 cm myocardial thickness model.…”

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confidence: 86%

Assessment of left ventricular mass by SPECT MPI

Packard

Maddahi

2019

Journal of Nuclear Cardiology

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A. Gimelli, R. Liga et al. report on left ventricular (LV) mass determination using two commercially available softwares that they applied to cadmium-zinc-telluride (CZT) single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI), and compared results to cardiac magnetic resonance imaging (MRI) which was the reference standard. 1 For their study, they retrospectively identified n = 25 patients who underwent MPI with gated 99m Tc-tetrofosmin acquired on a CZT camera and had a cardiac MRI within 12 ± 3 weeks. To put the authors' work on LV mass determination in perspective, we will address the importance, accepted methods, and nuclear imaging approaches to LV mass measurement.A common cardiac adaptive mechanism in the setting of hemodynamic overload is the compensatory increase in LV mass, as explained by the Law of LaPlace in whichwhere s is the ventricular wall stress, P is the ventricular pressure, r is the ventricular radius, and T is the ventricular wall thickness. 2 However, this compensatory increase in ventricular wall thickness is detrimental on the long run, as demonstrated by multiple clinical studies. Indeed, an increase in LV wall thickness or mass, typically due to left ventricular hypertrophy (LVH), predicts an increased risk of cardiovascular morbidity and mortality as determined in the Framingham Heart Study, even after adjustment for major risk factors. 3 Moreover, the severity of LVH is an independent predictor of death and coronary revascularization. 4 These early observations have been confirmed by more contemporary data where LV mass and LVH were found to be predictive of the need for future revascularization, 5 and of the occurrence of myocardial infarction and cardiac death 6 in patients with or without stress-inducible ischemia 7 or in the setting of asymptomatic aortic stenosis. 8 In patients with a previous myocardial infarction, prognosis is related to the percentage of viable LV mass, and LV mass measurement can assess the development of compensatory focal LVH. 9 Quantification of LV mass is also useful in the evaluation and management of patients with valvular heart disease and hypertrophic cardiomyopathy. Further, LV mass has been demonstrated to predict the incidence of congestive heart failure in the Multi-Ethnic Study of Atherosclerosis. 10 In addition, assessment of LV mass can be used to monitor response to therapies such as weight reduction 11 or kidney transplantation. 12

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confidence: 86%

Assessment of left ventricular mass by SPECT MPI

Packard

Maddahi

2019

Journal of Nuclear Cardiology

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“…As far as measurement of global function is concerned, the ECTb performs a Fourier decomposition of the time-volume (T-V) curve that describes the LV cavity volume as a function of the cardiac cycle, then takes the first Fourier harmonic to estimate end-systolic (ES) and end-diastolic (ED) volumes-as a result, T-V curve estimates are less dependent on temporal sampling, and ejection fractions (EFs), EDVs and ESVs from 8-frame and 16-frame gated acquisitions will be relatively close in value. 2 In contrast, QGS/QPS measures the actual dynamic range of the T-V curve, which is directly proportional to the frequency of temporal sampling-in other words, 8-frame ESVs will be larger, EDVs smaller, and EFs lower compared to 16-frame gated acquisitions, with a substantially uniform difference of 3-4 EF points over the entire EF range. 4 With regard to myocardial thickening, the ECTb algorithm assumes a uniform myocardial thickness of 1 cm at ED, and increases it with a 1:1 relationship to the apparent myocardial ''brightening'' from ED to ES, since partial volume effect is fairly linear for the reconstructed spatial resolutions and myocardial thicknesses of interest.…”

Section: Different Algorithms Are Based On Different Computational Tomentioning

confidence: 99%

“…The specific software packages used by Alexiou et al are Emory University's Cardiac Toolbox (ECTb), 2 Cedars-Sinai's Cardiac Suite (QGS/QPS), 3 and General Electric's Myovation. This writer is not aware of any published papers detailing the technical principles on which the Myovation software is based, but the other two algorithms and their differing characteristics have been well described in the literature.…”

Section: Different Algorithms Are Based On Different Computational Tomentioning

confidence: 99%

Quantitative measurements of myocardial perfusion and function from SPECT (and PET) studies depend on the method used to perform those measurements

Germano

2018

Journal of Nuclear Cardiology

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See related article, pp. 911-924One would perhaps be justified to remark that the title of this editorial only states the obvious and that its premise ought to be accepted by any reasonable reader, even if not particularly familiar with nuclear cardiology. Nevertheless, the paper to which the editorial refers, 1 describing good concordance but also substantial differences amongst three commercially available software packages to quantify LV perfusion and function from gated myocardial SPECT, offers us the opportunity to reflect on some of the specific reasons why those differences exist. As the authors describe in their comprehensive review of the published literature, a wealth of studies exists assessing the cross-correlation of the outputs of different quantitative gated SPECT algorithms, and the current study confirms previously reported findings, albeit in a larger population of 634 consecutive patients. Let us try to interpret and clarify those findings, while framing them in a more general context. DIFFERENT ALGORITHMS ARE BASED ON DIFFERENT COMPUTATIONAL TOOLS (AND WORKING ASSUMPTIONS)The specific software packages used by Alexiou et al are Emory University's Cardiac Toolbox (ECTb), 2Cedars-Sinai's Cardiac Suite (QGS/QPS), 3 and General Electric's Myovation. This writer is not aware of any published papers detailing the technical principles on which the Myovation software is based, but the other two algorithms and their differing characteristics have been well described in the literature. As far as measurement of global function is concerned, the ECTb performs a Fourier decomposition of the time-volume (T-V) curve that describes the LV cavity volume as a function of the cardiac cycle, then takes the first Fourier harmonic to estimate end-systolic (ES) and end-diastolic (ED) volumes-as a result, T-V curve estimates are less dependent on temporal sampling, and ejection fractions (EFs), EDVs and ESVs from 8-frame and 16-frame gated acquisitions will be relatively close in value. 2 In contrast, QGS/QPS measures the actual dynamic range of the T-V curve, which is directly proportional to the frequency of temporal sampling-in other words, 8-frame ESVs will be larger, EDVs smaller, and EFs lower compared to 16-frame gated acquisitions, with a substantially uniform difference of 3-4 EF points over the entire EF range. 4 With regard to myocardial thickening, the ECTb algorithm assumes a uniform myocardial thickness of 1 cm at ED, and increases it with a 1:1 relationship to the apparent myocardial ''brightening'' from ED to ES, since partial volume effect is fairly linear for the reconstructed spatial resolutions and myocardial thicknesses of interest. 2 QGS/QPS is also based, in part, on myocardial brightening, but uses phantom calibration to estimate ED thickness, and asymmetrical Gaussian fitting with a constant myocardial mass constraint to follow the endocardium and epicardium's location throughout the cardiac cycle. 3 As for perfusion quantification, aside from the different myocardial sampling techniques (hy...

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“…This local variability measure is used in most clinical implementations of the relative quantification. [1][2][3][4] to derive the severity of the local perfusion decrease and consequently overall measures of hypoperfusion such as defect extent or perfusion deficit. Therefore, although a phantom study is a useful test for evaluation of the differences in relative perfusion distribution in the uniform myocardium related to the scanner hardware and reconstruction methods (abstracting it from patient or physiological differences), it is less applicable to testing the variability of the real-world inter-patient database.…”

Section: Should We Study Patients or Phantoms?mentioning

confidence: 99%

“…This is accomplished by local comparisons of test patients to other scans of normal patients in most current quantitative SPECT MPI methods. [1][2][3][4] These comparisons allow identification of local areas of hypoperfusion, typically in polar map coordinates. The set of normal patients is usually referred to as ''normal database'' or ''normal limits'' (when a collection of databases is considered, for example stress and rest databases).…”

Section: Introductionmentioning

confidence: 99%