Reduced Homogeneous Myocardial [\({}^{18}\)F]FDG Uptake in Routine PET/CT Studies as an Early Indicator of Chemotherapy-Induced Cardiotoxicity  
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1 Biomedical Engineering and Telemedicine Centre, ETSI Telecomunicacion, Center for Biomedical Technology, Universidad Politecnica de Madrid, 28040 Madrid, Spain;  
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3 Facultad de Medicina, Universidad Complutense de Madrid, 28040 Madrid, Spain;  
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1 Facultad de Medicina, Universidad Complutense de Madrid, 28040 Madrid, Spain;  
[PERSON]  
1 Facultad de Medicina, Universidad Complutense de Madrid, 28040 Madrid, Spain;  
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1 Facultad de Medicina, Universidad Complutense de Madrid, 28040 Madrid, Spain;  
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cardiotoxic drugs that can cause cardiac damage or other cardiovascular alterations and are responsible for increased morbidity and mortality in cancer survivors [2; 3; 4; 5; 6; 7]. Since the occurrence of cardiotoxicity is associated with poor prognosis [3; 5], identifying it at an early subclinical stage is of vital importance to prevent it, establish cardioprotective treatments, and/or change chemotherapy schemes. Strategies for early detection of cardiotoxicity have been recently proposed in clinical cardio-oncology guidelines endorsed by the European Society of Cardiology [8] and include adequate risk stratification, the detection of abnormal serum biomarkers, such as troponin of natriuretic peptides, or performing cardiac imaging techniques [2; 3; 4], such as echocardiography or cardiac magnetic resonance (CMR). Given its safety, availability, reproducibility, and low cost, 2D ultrasound is the first-line method for the assessment of ventricular function changes, heart failure risk stratification, and treatment management [8]. However, other advanced imaging techniques, including 3D echocardiography [9], assessing myocardial deformation (global longitudinal strain) [10; 11; 12], or tissue characterization with CMR are now available to increase the sensitivity for the diagnosis of subtle myocardial damage [3; 4]. The current clinical procedures are designed to detect cardiotoxicity when myocardial damage has already been established, not before. In this context, the use of positron emission tomography/computed tomography (PET/CT) studies with [18F]fluorodeoxyglucose ([18F]FDG) in oncological patients is now widely used both for the diagnosis and assessment of treatment response and follow-up. In recent years, and despite the difficult interpretation, different findings using [18F]FDG PET have been proposed as potentially useful for early identification of cardiotoxicity, including uptake levels [13; 14; 15; 16] or uptake patterns [17; 18; 19]. However, most of these studies lack standardized segmentation and quantification methods or a study population with echocardiography confirmed by cardiotoxicity diagnosis or even a control group. Therefore, baseline and follow-up oncologic [18F]FDG PET images are not used for the early identification of abnormalities in myocardial metabolism in current routine clinical practice. Furthermore, the changes in cardiac metabolism that suggest cardiotoxicity are not well established yet. Whereas previous research has suggested that an increased myocardial uptake occurs due to the effect of chemotherapy [13; 14; 15; 16; 19; 20; 21; 22; 23; 24], it appears that decreased uptake may be more specific of myocardial damage [25]. New measurement tools, such as radiomic-based quantification methods [26; 27; 28; 29; 30; 31] integrated into the analysis of [18F]FDG PET/CT, may provide insight into the early changes occurring in cardiac metabolism associated with cardiotoxicity and would allow the implementation of personalized therapies aimed at preventing the deterioration of cardiac function.