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Limitations of quantitative phase analysis of radionuclide angiograms for detecting coronary artery disease in
Insights
Standard deviation of the left ventricular (LV) peak (SDP-LV) effectively identifies coronary artery disease (CAD) in patients with normal or moderately impaired LV function. However, its specificity decreases with severe LV impairment.
Area of Science:
- Cardiology
- Nuclear Medicine
- Medical Imaging
Background:
- Phase analysis of radionuclide ventriculograms assesses left ventricular (LV) wall motion synchronicity.
- Standard deviation of the LV peak (SDP-LV) quantifies this synchronicity.
Purpose of the Study:
- To evaluate the sensitivity and specificity of SDP-LV for detecting coronary artery disease (CAD).
- To assess the impact of left ventricular (LV) impairment on SDP-LV accuracy.
Main Methods:
- Studied 84 patients: 45 with CAD, 39 with cardiomyopathy/valvular disease.
- Grouped patients by LV ejection fraction (EF): Group I (≥50%), Group II (35-50%), Group III (<25%).
- Analyzed resting and exercise SDP-LV values.
Main Results:
- SDP-LV showed high specificity for CAD in Groups I and II (48-89% at rest, increasing with exercise).
- In Group III (severe LV impairment), SDP-LV remained sensitive but lost specificity.
- Phase analysis accurately identified CAD in patients with normal or moderately depressed LV function.
Conclusions:
- SDP-LV is a sensitive and specific tool for CAD detection in patients with normal to moderate LV dysfunction.
- Phase analysis is less reliable for differentiating CAD in severe LV impairment.
Abstract:
Phase analysis of radionuclide ventriculograms is used for identifying ischemic wall motion abnormalities. Myocardial segments with an abnormal phase, that is, delayed onset of wall motion, can be localized on a phase distribution image, and the synchronicity of left ventricular (LV) wall motion can be assessed from a histogram of LV phase distribution. The standard deviation of the LV peak on this histogram (SDP-LV) describes the width of the peak and is used as an index of the synchronicity of wall motion. We examined in this study the sensitivity of SDP-LV for identifying coronary artery disease (CAD) and its specificity in patients with normal and various degrees of LV impairment. A total of 84 patients were studied. Forty-five patients had CAD and 39 had congestive cardiomyopathy or valvular heart disease. Patients were grouped according to their LV ejection fraction (EF). In group I (37 patients) resting LVEF was equal to or greater than 50%, in group II (24 patients) it ranged from 35% to 50%, and in group III (23 patients) it was less than 25%. SDP-LV was highly specific in groups I and II for CAD with sensitivities of 48% and 89% at rest that increased with exercise to 88% and 100%. In group III patients, SDP-LV remained highly sensitive but was no longer specific for CAD. Therefore, in severe LV impairment, phase analysis does not aid in distinguishing CAD from other causes of ventricular dysfunction. By contrast, phase analysis is highly sensitive and specific for CAD in patients with normal or moderately depressed LV function.