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Updated: Aug 23, 2026
In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography
Published on: February 16, 2016
Classification of ischemic dysfunctional myocardium combining perfusion quantification and contractile reserve
R Sciagrà1, M Leoncini, A Mennuti
1Unit of Nuclear Medicine, Department of Clinical Physiopatology, University of Florence, Florence, Italy. r.sciagra@dfc.unifi.it
Insights
Dobutamine gated single-photon emission computed tomography (SPECT) accurately differentiates scarred from viable myocardium. Combining contractile reserve and perfusion imaging improves classification of dysfunctional heart segments.
Area of Science:
- Cardiology
- Nuclear Medicine
- Medical Imaging
Background:
- Differentiating scarred from hibernating myocardium in ischemic cardiomyopathy is crucial for treatment decisions.
- Current viability assessment methods may oversimplify the complex nature of dysfunctional myocardial segments.
Purpose of the Study:
- To evaluate a more complex classification of dysfunctional myocardial segments.
- To assess the utility of gated single-photon emission computed tomography (SPECT) with dobutamine and nitrate enhancement for viability detection.
Main Methods:
- Gated SPECT (resting, nitrate-enhanced, and dobutamine stress) was performed before revascularization in 35 patients.
- Postrevascularization SPECT assessed functional recovery, defining scar, stunned, or hibernating segments.
- Prerevascularization SPECT categorization was compared against this reference standard.
Main Results:
- Dobutamine SPECT accurately differentiated scarred from viable segments (78% accuracy).
- Nitrate imaging revealed significantly higher tracer activity increase in hibernating segments compared to scar or stunned segments (p<0.0001).
- Nitrate-induced activity increase predicted postrevascularization perfusion and distinguished hibernating from stunned segments.
Conclusions:
- Combining contractile reserve (dobutamine SPECT) and perfusion quantification (nitrate-enhanced SPECT) provides a comprehensive classification of dysfunctional myocardial segments.
- This integrated imaging approach enhances the assessment of myocardial viability in ischemic cardiomyopathy.
Aim:
In patients with ischemic cardiomyopathy, the differentiation of dysfunctional myocardium in scarred versus hibernating is oversimplified. We evaluated a more complex classification using an imaging technique currently employed for viability detection, having as reference the postrevascularization outcome of dysfunctional segments.
Methods:
In 35 patients, we performed gated single-photon emission computed tomography (SPECT) (resting and nitrate-enhanced study, the latter with baseline and dobutamine acquisition) before revascularization. The outcome after revascularization was assessed by repeating resting gated SPECT. Dysfunctional segments without functional recovery in postrevascularization gated SPECT were defined scar (either nontransmural or transmural according to tracer activity); those with recovery were divided in stunned (unchanged uptake) or hibernating (improved postrevascularization activity). This reference classification was compared with the categorization based on prerevascularization gated SPECT.
Results:
Contractile reserve in dobutamine gated SPECT differentiated scarred from viable segments with 78% accuracy. Tracer activity in nitrate imaging distinguished the degree of transmurality. Nitrate-induced activity increase was significantly higher (p<0.0001) in the hibernating segments (14.9+/-20.4%) than in transmural (4.8+/-13.4%) nontransmural scars (3.3+/-13%), or stunned segments (2.2+/-8%). The presence or absence of nitrate-induced activity increase predicted the postrevascularization perfusion changes in viable myocardium and differentiated hibernating from stunned segments. The prerevascularization classification showed a good agreement with the reference categorization (kappa=0.50). Conclusion. Combining contractile reserve evaluation and perfusion quantification within a single study with baseline-nitrate gated SPECT and dobutamine test it is possible to achieve a comprehensive classification of dysfunctional segments.
