title: Seasonal Temperature Changes Do Not Affect Cardiac Glucose Metabolism.
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.
authors: Department of Nuclear Medicine, HUS Medical Imaging Center, Helsinki University Central Hospital, Haartmaninkatu 4, 00029 Helsinki, Finland.
authors: Jukka
authors: J
authors: Schildt
authors: Department of Nuclear Medicine, HUS Medical Imaging Center, Helsinki University Central Hospital, Haartmaninkatu 4, 00029 Helsinki, Finland.
authors: Antti
authors: A
authors: Loimaala
authors: Department of Nuclear Medicine, HUS Medical Imaging Center, Helsinki University Central Hospital, Haartmaninkatu 4, 00029 Helsinki, Finland.
authors: Eero
authors: E
authors: Hippeläinen
authors: Department of Nuclear Medicine, HUS Medical Imaging Center, Helsinki University Central Hospital, Haartmaninkatu 4, 00029 Helsinki, Finland.
authors: Päivi
authors: P
authors: Nikkinen
authors: Department of Nuclear Medicine, HUS Medical Imaging Center, Helsinki University Central Hospital, Haartmaninkatu 4, 00029 Helsinki, Finland.
authors: Aapo
authors: A
authors: Ahonen