Automatic calculation of myocardial external efficiency using a single 11C-acetate PET scan

Hendrik J Harms,Nils Henrik S Hansson,Tanja Kero,Tomasz Baron,Lars P Tolbod,Won Y Kim,Jørgen Frøkiær,Frank A Flachskampf,Henrik Wiggers,Jens Sörensen

doi:10.1007/s12350-018-1338-0

Hendrik J Harms, Nils Henrik S Hansson + Show 8 more

Open Access

https://doi.org/10.1007/s12350-018-1338-0

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Abstract

BackgroundMyocardial external efficiency (MEE) is defined as the ratio of kinetic energy associated with cardiac work [forward cardiac output (FCO)*mean systemic pressure] and the chemical energy from oxygen consumed (MVO2) by the left ventricular mass (LVM). We developed a fully automated method for estimating MEE based on a single 11C-acetate PET scan without ECG-gating. Methods and ResultsTen healthy controls, 34 patients with aortic valve stenosis (AVS), and 20 patients with mitral valve regurgitation (MVR) were recruited in a dual-center study. MVO2 was calculated using washout of 11C -acetate activity. FCO and LVM were calculated automatically using dynamic PET and parametric image formation. FCO and LVM were also obtained using cardiac magnetic resonance (CMR) in all subjects. The correlation between MEEPET-CMR and MEEPET was high (r = 0.85, P < 0.001) without significant bias. MEEPET was 23.6 ± 4.2% for controls and was lowered in AVS (17.2 ± 4.3%, P < 0.001) and in MVR (18.0 ± 5.2%, P = 0.004). MEEPET was strongly associated with both NYHA class (P < 0.001) and the magnitude of valvular dysfunction (mean aortic gradient: P < 0.001, regurgitant fraction: P = 0.009). ConclusionA single 11C-acetate PET yields accurate and automated MEE results on different scanners. MEE might provide an unbiased measurement of the phenotypic response to valvular disease.

Highlights

A common feature in most cardiomyopathies is a reduction in myocardial external efficiency (MEE)[1] i.e., an imbalance between cardiac work and total energy consumption by the left ventricle (LV)
Myocardial external efficiency (MEE) might provide an unbiased measurement of the phenotypic response to valvular disease. (J Nucl Cardiol 2018;25:1937–44.)
Preserving or restoring MEE is associated with better prognosis and a reduction of symptoms in patients with left ventricular systolic dysfunction,[2] dilated cardiomyopathy,[3,4] aortic valve stenosis,[5] and hypertrophic cardiomyopathy[6] and was suggested as a therapeutic target

Summary

Introduction

A common feature in most cardiomyopathies is a reduction in myocardial external efficiency (MEE)[1] i.e., an imbalance between cardiac work and total energy consumption by the left ventricle (LV). The gold standard for measuring MEE makes use of pressure-volume loops and the Fick-principle to estimate cardiac work and myocardial oxygen consumption (MVO2), respectively. Accurate non-invasive alternatives are available,[9] requiring positron emission tomography (PET) with either a combination of 15O-labeled PET tracers or, more commonly, 11C-acetate washout[10,11,12] to assess MVO2, combined with cardiac magnetic resonance imaging (CMR) or echocardiography to assess Cardiac Output (CO) and LV mass (LVM). Myocardial external efficiency (MEE) is defined as the ratio of kinetic energy associated with cardiac work [forward cardiac output (FCO)*mean systemic pressure] and the chemical energy from oxygen consumed (MVO2) by the left ventricular mass (LVM). We developed a fully automated method for estimating MEE based on a single 11C-acetate PET scan without ECG-gating

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