Quantitation in gated perfusion SPECT imaging: The Cedars-Sinai approach

Germano, Guido; Kavanagh, Paul; Slomka, Piotr J.; Kriekinge, Serge D. Van; Pollard, Graham; Berman, Daniel S.

doi:10.1016/j.nuclcard.2007.06.008

Cited by 227 publications

(168 citation statements)

References 78 publications

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“…It is well known that ESV is underestimated in subjects with small hearts in QGS software [27]. Our study showed that there was a difference in EDV and LVEF between LEHR and IQ-SPECT.…”

Section: Functional Analysissupporting

confidence: 47%

Nuclear myocardial perfusion imaging using thallium-201 with a novel multifocal collimator SPECT/CT: IQ-SPECT versus conventional protocols in normal subjects

et al. 2015

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Objective: A novel multifocal collimator, IQ-SPECT (Siemens) consists of cardio-centric and 3D iterative SPECT reconstruction and makes it possible to perform MPI scans in a short time. The aims are to delineate the normal uptake in thallium-201 ( 201 Tl) SPECT in each acquisition method and to compare the distribution between new and conventional protocol, especially in patients with normal imaging.Methods: Forty patients (eight women, mean age of seventy-five years) who underwent myocardial perfusion imaging were included in the study. All patients underwent one-day protocol perfusion scan after an adenosine-stress test and at rest after administrating 201 Tl and showed normal results. Acquisition was performed on a Symbia T6 equipped with a conventional dual-headed gamma camera system (Siemens ECAM) and with a multifocal collimator called IQ-SPECT. Imaging was performed with a conventional system followed by IQ-SPECT/computed tomography (CT).Reconstruction was performed with or without X-ray CT-derived attenuation correction (AC). Two nuclear physicians blinded to clinical information interpreted all MPI studies.A semi-quantitative myocardial perfusion was analyzed by a 17-segment model with a 5-point visual scoring. The uptake of each segment was measured and left ventricular functions were analyzed by QPS software.Results: IQ-SPECT provided good or excellent image quality. IQ-SPECT images without AC were similar to those of conventional LEHR study. Mid-inferior defect score (0.3±0.5) in conventional LEHR study was increased significantly in IQ-SPECT with AC (0±0). IQ-SPECT (AC) improved the mid-inferior decreased perfusion shown in conventional images. The apex in IQ-SPECT (AC) was decreased compared to that in LEHR (0.1±0.3 vs. 0.5±0.7, p<0.05). The left ventricular ejection fraction from IQ-SPECT was significantly higher than that from the LEHR collimator (p=0.0009). Conclusion:The images of IQ-SPECT acquired in a short time are equivalent with that of conventional LEHR. The results indicated that the IQ-SPECT system with attenuation correction is capable of correcting inferior artifacts with high image quality.(Ann Nucl Med)

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“…It is well known that ESV is underestimated in subjects with small hearts in QGS software [27]. Our study showed that there was a difference in EDV and LVEF between LEHR and IQ-SPECT.…”

Section: Functional Analysissupporting

confidence: 47%

Nuclear myocardial perfusion imaging using thallium-201 with a novel multifocal collimator SPECT/CT: IQ-SPECT versus conventional protocols in normal subjects

et al. 2015

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“…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%

“…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 (hybrid cylindrical/spherical for ECTb, ellipsoidal for QGS/QPS), the …”

mentioning

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%