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Updated: Aug 29, 2026
MRI and PET in Mouse Models of Myocardial Infarction
Published on: December 19, 2013
Dobutamine-tagged MRI for inotropic reserve assessment in severe CAD: relationship with PET findings
Alejandro N Mazzadi1, Marc F Janier, Benjamin Brossier
1Unité Mixte de Recherche-Centre National de la Recherche Scientifique 5515, Centre de Recherche et d'Applications en Traitement de l'Image et du Signal, Lyon, France.
Insights
In severe coronary artery disease (CAD), the inotropic reserve does not correlate with resting perfusion. However, it is inversely related to resting contractile function, except in hibernating myocardium.
Area of Science:
- Cardiology
- Medical Imaging
- Physiology
Background:
- The relationship between reduced blood flow and intramyocardial inotropic reserve in coronary artery disease (CAD) remains unclear.
- Assessing myocardial function and viability is crucial for managing CAD patients.
Purpose of the Study:
- To investigate the link between positron emission tomography (PET) findings (perfusion, glucose uptake) and tagged magnetic resonance imaging (tagged MRI) strain values in severe CAD.
- To evaluate the intramyocardial inotropic reserve in relation to myocardial viability and contractile function under dobutamine stress.
Main Methods:
- Eighteen patients with severe CAD underwent tagged MRI (rest and dobutamine) and H2(15)O/18F-fluorodeoxyglucose PET.
- Regional midmyocardial circumferential shortening (Ecc) and PET patterns (normal, match viable, mismatch viable, infarcted) were analyzed.
- Correlation between resting Ecc, perfusion, and glucose uptake was assessed.
Main Results:
- Resting Ecc correlated with both perfusion (r=0.49) and glucose uptake (r=0.58).
- Inotropic reserve was present in similar proportions across normal, match viable, and infarcted regions, but higher in mismatch viable regions.
- The extent of inotropic reserve was lower in infarcted regions.
- At similar perfusion levels, inotropic reserve was inversely related to resting contractile performance, except in hibernating (mismatch viable) regions.
Conclusions:
- In severe CAD, the presence of inotropic reserve assessed by dobutamine stress does not correlate with resting myocardial perfusion.
- Myocardial inotropic reserve is inversely related to resting contractile performance at a similar perfusion level, but this association may not hold true for hibernating myocardium.
Abstract:
The impact of blood flow reductions on the intramyocardial inotropic reserve has not yet been established in coronary artery disease (CAD). We therefore evaluated in severe CAD the relationship between positron emission tomography (PET) patterns of perfusion and glucose uptake and the corresponding tagged magnetic resonance imaging (tagged MRI) values of midmyocardial strains under low-dose dobutamine. Eighteen patients underwent tagged MRI (at rest, with dobutamine) and H2(15)O/18F-fluorodeoxyglucose PET. Regional midmyocardial circumferential shortening (Ecc) and PET patterns (normal, match viable, mismatch viable, and infarcted) were assessed in three tagged MRI/PET short-axis slices. Regional Ecc at rest correlated with both perfusion (r = 0.49) and glucose uptake (r = 0.58). The presence of the inotropic reserve was similar in normal, match viable, and infarcted (approximately 40% of regions vs. 52% in mismatch viable, P < 0.05), but the extent of the increase after dobutamine was lower in infarcted regions (P = 0.06). Within each PET pattern, regions were grouped according to their Ecc values at rest into three categories (high, intermediate, and low contractile performance). In mismatch viable (hibernation), the inotropic reserve was similar among the three categories, but in the other PET patterns the presence and extent of the inotropic reserve was higher in those regions with lowest Ecc (without significant differences in perfusion). In severe CAD, the presence of the inotropic reserve assessed by midmyocardial changes under dobutamine does not relate to resting perfusion. At a similar level of perfusion, the presence of the inotropic reserve is inversely related to contractile performance at rest, but our results suggest that it may not be true for hibernating myocardium.
