Left ventricular cavity-to-myocardium count ratio in exercise and resting technetium-99m-tetrofosmin SPECT:...

Area of Science:

• Nuclear Cardiology
• Cardiovascular Imaging
• Radiopharmaceuticals

Background:

• Left ventricular ejection fraction (LVEF) is a critical indicator of cardiac function.
• Assessing LVEF in patients with coronary artery disease (CAD) is crucial for risk stratification and management.
• Technetium-99m (Tc-99m) tetrofosmin single photon emission computed tomography (SPECT) is a widely used imaging modality for myocardial perfusion.

Purpose of the Study:

• To evaluate the utility of the cavity-to-myocardium (C/M) count ratio derived from Tc-99m tetrofosmin SPECT.
• To determine if the C/M ratio can identify CAD patients with depressed LVEF at rest and during exercise.
• To correlate C/M ratios with independently measured LVEF.

Main Methods:

• Sixty patients with recent CAD were included in the study.
• Left ventricular ejection fraction (LVEF) was measured using first-pass ventriculography.
• Myocardial perfusion SPECT imaging was performed using Tc-99m tetrofosmin at rest and during exercise to calculate left ventricular C/M ratios.

Main Results:

• Patients with higher LVEF (>= 40%) demonstrated significantly higher C/M ratios compared to those with abnormal LVEF (< 40%) during both rest and exercise.
• No significant difference in C/M ratios was observed between rest and exercise conditions within either patient group.
• A significant correlation was found between exercise/rest LVEF and exercise/rest C/M ratios.

Conclusions:

• The Tc-99m tetrofosmin C/M ratio calculated from SPECT perfusion images is a valuable parameter.
• This ratio aids in identifying CAD patients with depressed LVEF.
• The C/M ratio offers a useful non-invasive method for assessing left ventricular systolic function in CAD.