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Relation between dobutamine trans-thoracic echocardiography, 99Tcm-MIBI and 18FDG uptake in chronic coronary artery
G Lucignani1, C Landoni, G Mengozzi
1INB-CNR, Department of Nuclear Medicine, University of Milan, Italy.
Insights
This study investigated myocardial viability in chronic coronary artery disease patients. Positron emission tomography with 18-fluorodeoxyglucose (18-FDG PET) uptake complements perfusion imaging and dobutamine echocardiography, especially in severely dysfunctional segments.
Area of Science:
- Cardiology
- Nuclear Medicine
- Medical Imaging
Background:
- Chronic coronary artery disease (CAD) often leads to left ventricular dysfunction.
- Assessing myocardial viability is crucial for guiding treatment strategies in CAD patients.
- Dobutamine stress echocardiography and perfusion imaging are common methods, but their utility in severely dysfunctional segments is debated.
Purpose of the Study:
- To examine the relationships between resting myocardial asynergy, dobutamine response, perfusion, and glucose metabolism in patients with chronic CAD and left ventricular dysfunction.
- To compare the diagnostic information provided by dobutamine stress echocardiography, myocardial perfusion imaging, and 18-FDG PET.
Main Methods:
- Evaluated 12 patients with chronic CAD and left ventricular dysfunction.
- Assessed myocardial perfusion using 99Tcm-methoxyisobutylisonitrile (MIBI) SPECT.
- Assessed myocardial wall motion with echocardiography and low-dose dobutamine.
- Assessed myocardial metabolism using 18-fluorodeoxyglucose (18-FDG) PET in a fasting state.
Main Results:
- Good agreement was observed between dobutamine-responsive segments and 18-FDG positive segments in moderately hypoperfused and hypokinetic areas.
- Fewer dobutamine-responsive segments than 18-FDG positive segments were found in hypoperfused and akinetic segments.
- 18-FDG uptake was present in 50% of severely hypoperfused and akinetic/dyskinetic segments unresponsive to dobutamine.
Conclusions:
- In severely hypoperfused and akinetic/dyskinetic segments, dobutamine stress echocardiography offers limited additional information beyond rest echocardiography and perfusion studies.
- 18-FDG uptake assessment provides complementary information to perfusion imaging and dobutamine echocardiography, aiding in the evaluation of myocardial viability.
Abstract:
The relationships between rest conditions of myocardial asynergy, response to dobutamine administration, perfusion and glucose metabolism were examined in 12 patients with chronic coronary artery disease and left ventricular dysfunction. We evaluated (1) rest and stress myocardial perfusion by 99Tcm-methoxyisobutylisonitrile (MIBI) and single photon emission tomography (SPET), (2) rest myocardial segmental wall motion by trans-thoracic echocardiography and low-dose dobutamine, and (3) myocardial metabolism by [18F]-2-fluoro-2-deoxy-D-glucose (18-FDG) and positron emission tomography (PET), in the fasting state. The analysis was carried out on 16 left ventricular myocardial segments. The SPET studies were analysed semi-quantitatively by normalization to the peak activity. Wall motion was assessed by a visual score. An 18FDG index was determined as the tissue/blood pool radioactivity ratio in each segment. The results showed: (1) remarkably good agreement between the number of dobutamine responsive segments and 18FDG positive segments among those that were only moderately hypoperfused and hypokinetic; (2) a smaller number of dobutamine responsive segments than 18FDG positive segments among those that were hypoperfused and akinetic; and (3) the presence of 18FDG in 50% of the segments that were severely hypoperfused and akinetic or dyskinetic and without improvement with dobutamine. These results indicate that in severely hypoperfused and akinetic or dyskinetic segments, trans-thoracic echocardiography under inotropic stimulation provides little additional information compared with that obtained with rest echocardiography and perfusion studies; the assessment of 18FDG uptake provides information that is complementary to that obtained by perfusion assessment, rest and dobutamine trans-thoracic echocardiography.