Comparison of diagnostic performance of four software packages for phase dyssynchrony analysis in gated myocardial perfusion SPECT

Abstract

BackgroundPhase analysis of gated myocardial perfusion single-photon emission computed tomography (SPECT) for assessment of left ventricular (LV) dyssynchrony was investigated using the following dedicated software packages: Corridor4DM (4DM), cardioREPO (cREPO), Emory Cardiac Toolbox (ECTb), and quantitative gated SPECT (QGS). The purpose of this study was to evaluate the normal values of 95% histogram bandwidth, phase standard deviation (SD), and entropy and to compare the diagnostic performance of the four software packages. A total of 122 patients with normal myocardial perfusion and cardiac function (58.9 ± 12.3 years, 60 women, ejection fraction (EF) 74.3 ± 5.7%, and end-diastolic volume (EDV) 83.5 ± 3.6 mL) and 34 patients with suspected LV dyssynchrony (64.1 ± 12.2 years, 9 women, EF 52.0 ± 18.0%, and EDV 145.0 ± 6.8 mL) who underwent Tc-99m methoxy-isobutyl-isonitrile/tetrofosmin gated SPECT were retrospectively evaluated. Dyssynchrony indices of the 95% histogram bandwidth, phase SD, and entropy were computed with the four software programs. Diagnostic performance of LV phase dyssynchrony assessments was determined by receiver operator characteristic (ROC) analysis. The area under the ROC curve (AUC) was used to compare the software programs. The optimal cutoff point was determined by ROC curve based on the Youden index.ResultsThe average of normal bandwidth significantly differed among the four software programs except in the comparison of 4DM and ECTb. Moreover, the normal phase SD significantly differed among the four software programs except in the comparison of cREPO and ECTb. The software programs showed high correlation levels for bandwidth, phase SD, and entropy (r ≥ 0.73, p < 0.001). ROC AUCs of bandwidth, phase SD, and entropy were ≥0.850, ≥0.858, and ≥0.900, respectively. Moreover, the ROC AUCs of bandwidth, phase SD, and entropy did not significantly differ among the four software programs. Optimal cutoff points for phase parameters were 24°–42° for bandwidth, 8.6°–15.3° for phase SD, and 31–48% for entropy.ConclusionsAlthough the optimal cutoff value for determining LV phase dyssynchrony by ROC analysis varied depending on the use of the different software programs, all software programs can be used reliably for phase dyssynchrony analysis.

Making the invisible visible: Phase dyssynchrony has potential as a new prognostic marker

“…Data were processed using the cardioREPO software. 7,12 among patients with a larger phase SD and bandwidth even in the absence of a definite perfusion defect. The QRS duration determined by electrocardiography was slightly longer in patients with MACE in agreement with dyssynchrony.…”

“…Whether phase analysis of dyssynchrony parameters provides additive information to conventional clinical parameters should be further examined. Lastly, due to dependence on software, values are not interchangeable, but Emory Cardiac Toolbox, QGS, Corridor 4DM, and cardioREPO software could be reliable tools for phase dyssynchrony analysis, 12 as well as Heart Function View. 7,8 Phase analysis is a potentially attractive method of evaluating dyssynchrony.…”

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

“…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). Moreover, the amount of injected radionuclide, stress or rest acquisition, the number of frames per cardiac cycle, and the type of software used for phase analysis 7,8 are important when computing entropy.…”

“…To understand relationships among bandwidth, phase SD, and entropy, the following example is extracted from our published work. 8 Among 156 patients who were assessed by 99m Tc-sestamibi or 99m Tc-tetrofosmin gated SPECT imaging, 122 were diagnosed with normal perfusion and cardiac function, and 34 patients with anomalous cardiac function had suspected LV dyssynchrony. Entropy was exponentially associated with bandwidth ( Figure 1a) and phase SD (Figure 1b).…”

Is it time for personalized cardiac resynchronization therapy

“…Phase analysis from gated SPECT imaging has been proposed as a relatively straightforward way of assessing dyssynchrony. 8 It uses Fourier harmonic function to approximate change in thickness of myocardium during a cardiac cycle to onset of contraction. This information of phase of onset of contraction is displayed on a polar map.…”