Background: ECG-gated single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy combined with phase analysis allows for the assessment of left ventricular dyssynchrony. However, there are several software programs available thereby introducing variability in outcome and normal values. The aim of this systematic review was to evaluate the variability between different programs as currently available in literature with a focus on normal values.
Methods: A systematic review was performed using the Embase, LILACS and Medline databases looking for articles reporting on normal values of the most used phase analysis parameters. The search resulted in 110 articles from Medline, 349 from Embase and one from LILACS. After exclusion of duplicate articles, 370 documents remained. Of these only 13 were deemed eligible for the systematic review.
Results: Phase SD and bandwidth are the main parameters used in dyssynchrony analysis. Most articles reviewed here used the Emory Cardiac ToolBox (ECTb) to determine the phase analysis parameters values, which varied greatly among the four software tested. The bandwidth and phase SD calculated by the Quantitative Gated SPECT (QGS) tends to be smaller than that calculated by the ECTb. In relation to the bandwidth, ECTb and cardioREPO (cREPO) have higher values than the other software programs. The value of entropy obtained from 4DM is lower than those obtained from QGS and cREPO.
Conclusion: We found that normal values of phase analysis can vary among software programs and can be different even when the same software is used.