Seasonal Temperature Changes Do Not Affect Cardiac Glucose Metabolism.

Jukka Schildt,Päivi Nikkinen,Antti Loimaala,Eero Hippeläinen,Aapo Ahonen

doi:10.1155/2015/916016

Jukka Schildt, Päivi Nikkinen + Show 3 more

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https://doi.org/10.1155/2015/916016

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Abstract

FDG-PET/CT is widely used to diagnose cardiac inflammation such as cardiac sarcoidosis. Physiological myocardial FDG uptake often creates a problem when assessing the possible pathological glucose metabolism of the heart. Several factors, such as fasting, blood glucose, and hormone levels, influence normal myocardial glucose metabolism. The effect of outdoor temperature on myocardial FDG uptake has not been reported before. We retrospectively reviewed 29 cancer patients who underwent PET scans in warm summer months and again in cold winter months. We obtained myocardial, liver, and mediastinal standardized uptake values (SUVs) as well as quantitative cardiac heterogeneity and the myocardial FDG uptake pattern. We also compared age and body mass index to other variables. The mean myocardial FDG uptake showed no significant difference between summer and winter months. Average outdoor temperature did not correlate significantly with myocardial SUVmax in either summer or winter. The heterogeneity of myocardial FDG uptake did not differ significantly between seasons. Outdoor temperature seems to have no significant effect on myocardial FDG uptake or heterogeneity. Therefore, warming the patients prior to attending cardiac PET studies in order to reduce physiological myocardial FDG uptake seems to be unnecessary.

Highlights

The 2-[18F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography combined with computed tomography (PET-CT) is a widely used method for evaluating cancer, and other disorders such as inflammation [1].The heart can use various substrates as oxidative fuel and rapidly adapts its substrate utilisation to meet supply
We found no significant difference in the patients’ myocardial FDG uptake between the summer and winter months (Figure 4)
Our findings indicate that outdoor temperature has no significant effect on myocardial glucose uptake and heterogeneity, so coefficient of variation (CoV) can be used to assess cardiac sarcoidosis

Summary

Introduction

The 2-[18F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography combined with computed tomography (PET-CT) is a widely used method for evaluating cancer, and other disorders such as inflammation [1].The heart can use various substrates as oxidative fuel and rapidly adapts its substrate utilisation to meet supply. The 2-[18F]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography combined with computed tomography (PET-CT) is a widely used method for evaluating cancer, and other disorders such as inflammation [1]. Fasting with or without a highfat, low-carbohydrate (HF-LCH) diet has been used to lower the physiological glucose metabolism in the myocardium, but there is no consensus over which protocol should be used in the diagnosis of cardiac sarcoidosis or in the assessment of cardiac viability [3]. Regulation of the myocardial carbohydrate metabolism is complex, and in addition to nutritional status, arterial substrates, and hormone levels, coronary flow and the inotropic state of the myocardium affect carbohydrate utilisation [4]. Results on the variability of intraindividual physiological myocardial FDG uptake over time remain controversial [5, 6], in the clinical setting variability can be substantial

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