Original ArticleImpact of ischemia on left ventricular dyssynchrony by phase analysis of gated single photon emission computed tomography myocardial perfusion imaging
Introduction
Recently, phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) has been introduced as an alternative method to the two-dimensional echocardiography in the evaluation of left ventricular (LV) dyssynchrony.1 The merits of phase analysis have been previously discussed but in summary include the automated nature of the analysis and the high reproducibility.2, 3, 4 In most such studies, the rest images are used to derive the standard deviation and bandwidth. Parenthetically, phase analysis could be performed on previously acquired images as the acquisition technique requires no modification over that used for conventional MPI, another important advantage. There is some concern that the use of stress images may not be reliable especially in the presence of large reversible defects. We hypothesized that since imaging is performed ~1 hour after tracer injection, the stress images should provide comparable information to rest images. A secondary hypothesis tested in the current study is whether the tracer dose affects the phase-derived indices.
Section snippets
Patient Selection
We studied two groups of patients, group-1 (N = 20) had reversible perfusion defects involving > 10% of the LV myocardium and group-2 (N = 20) had normal stress and rest MPI. The other selection criteria were (1) all patients had low dose stress and high dose rest images, (2) both the rest and stress images were obtained with same tracer, (3) all patients had normal LV ejection fraction (EF, >50%) by gated SPECT MPI, (4) none of the patients have any fixed perfusion defects, and (5) none of the
Results
The pertinent data are listed in Table 1. The MPI results are summarized in Table 2. A representative example from group-1 is shown in Figure 1.
The standard deviation and bandwidth were similar in the two groups. The change (stress–rest) in standard deviation and bandwidth in the two groups were not statistically significant (Table 2). There was no significant difference in the rest or stress standard deviation or bandwidth in either group (Table 2 and Figure 2). There was no correlation
Discussion
This is the first study to evaluate changes in mechanical dyssynchrony indices by phase analysis in relation to the presence of reversible perfusion defects. The main findings support our hypothesis that the presence of even a large reversible perfusion defect “ischemia” did not alter the phase-derived standard deviation and histogram bandwidth. Further, comparable data were obtained with use of low dose and high dose of the same radiotracer. This study has important applications, especially in
Conflicts of interest
None.
References (19)
- et al.
Onset of left ventricular mechanical contraction as determined by phase analysis of ECG-gated myocardial perfusion SPECT imaging: Development of a diagnostic tool for assessment of cardiac mechanical dyssynchrony
J Nucl Cardiol
(2005) - et al.
Evaluation of left ventricular mechanical dyssynchrony as determined by phase analysis of ECG-gated SPECT myocardial perfusion imaging in patients with left ventricular dysfunction and conduction disturbances
J Nucl Cardiol
(2007) - et al.
Evaluation of mechanical dyssynchrony and myocardial perfusion using phase analysis of gated SPECT imaging in patients with left ventricular dysfunction
J Nucl Cardiol
(2008) - et al.
Relation of left-ventricular dyssynchrony by phase analysis of gated SPECT images and cardiovascular events in patients with implantable cardiac defibrillators
J Nucl Cardiol
(2010) - et al.
Myocardial perfusion and function: Single photon emission computed tomography
J Nucl Cardiol
(2007) - et al.
Corridor4DM: The Michigan method for quantitative nuclear cardiology
J Nucl Cardiol
(2007) - et al.
Automated assessment of serial SPECT myocardial perfusion images
J Nucl Cardiol
(2009) - et al.
Quantitative assessment of myocardial perfusion abnormality on SPECT myocardial perfusion imaging is more reproducible than expert visual analysis
J Nucl Cardiol
(2009) - et al.
Temporal resolution of multiharmonic phase analysis of ECG-gated myocardial perfusion SPECT studies
J Nucl Cardiol
(2008)
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