The clinical applications of positron emission tomography/computed tomography (PET-CT) with the glucose analogue 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) extend beyond the field of oncology.
In the Heart
FDG uptake by the myocardium allows assessment of myocardial viability in patients with left ventricular dysfunction and coronary artery disease who are planning to undergo coronary revascularization, revealing potential areas of hibernating myocardium with viable myocardial tissue. In fact, in many centers, cardiac FDG PET/CT is becoming the gold standard for assessing myocardial viability. Cardiac FDG PET/CT has high sensitivity of 88% and specificity of 80% when proper preparation is performed (prolonged fasting, increased fat intake and minimal carbohydrate intake the previous day).
In patients with cardiac sarcoidosis, FDG PET/CT has proven to be a useful tool for disease monitoring. It is worth noting that a high percentage of patients with cardiac sarcoidosis have arrhythmias and implantable cardiac devices that may interfere with cardiac magnetic resonance imaging examination.
In the Heart
FDG uptake by the myocardium allows assessment of myocardial viability in patients with left ventricular dysfunction and coronary artery disease who are planning to undergo coronary revascularization, revealing potential areas of hibernating myocardium with viable myocardial tissue. In fact, in many centers, cardiac FDG PET/CT is becoming the gold standard for assessing myocardial viability. Cardiac FDG PET/CT has high sensitivity of 88% and specificity of 80% when proper preparation is performed (prolonged fasting, increased fat intake and minimal carbohydrate intake the previous day).
In patients with cardiac sarcoidosis, FDG PET/CT has proven to be a useful tool for disease monitoring. It is worth noting that a high percentage of patients with cardiac sarcoidosis have arrhythmias and implantable cardiac devices that may interfere with cardiac magnetic resonance imaging examination.
In Atherosclerosis
Atherosclerotic vessels take up FDG in the intima of large vessels such as the aorta and other major arteries. Increased metabolic activity from macrophages in the atherosclerotic plaque is responsible for FDG uptake. Smooth muscles in arterial walls also take up FDG and are visualized on PET/CT examination.
Atherosclerotic vessels take up FDG in the intima of large vessels such as the aorta and other major arteries. Increased metabolic activity from macrophages in the atherosclerotic plaque is responsible for FDG uptake. Smooth muscles in arterial walls also take up FDG and are visualized on PET/CT examination.
In the Brain
FDG uptake by cortical and subcortical structures allows non-invasive quantification of cerebral metabolism and can provide valuable information before any morphological changes become visible. Current evidence in patients with epilepsy shows that FDG PET can provide critical data guiding surgical resections of the epileptogenic zone for medically refractory epilepsy. A decade of brain PET research has also proven that brain FDG PET examination is an effective and safe method for detecting diagnostic patterns of glucose hypometabolism in neurodegenerative dementias. Differentiation of 3 major neurodegenerative disorders by 18F-FDG PET, such as Alzheimer's disease (AD), frontotemporal dementia (FTD), and dementia with Lewy bodies (DLB), have become established practice and an effective and useful complement to other diagnostic methods in evaluating patients with progressive cognitive decline.
FDG uptake by cortical and subcortical structures allows non-invasive quantification of cerebral metabolism and can provide valuable information before any morphological changes become visible. Current evidence in patients with epilepsy shows that FDG PET can provide critical data guiding surgical resections of the epileptogenic zone for medically refractory epilepsy. A decade of brain PET research has also proven that brain FDG PET examination is an effective and safe method for detecting diagnostic patterns of glucose hypometabolism in neurodegenerative dementias. Differentiation of 3 major neurodegenerative disorders by 18F-FDG PET, such as Alzheimer's disease (AD), frontotemporal dementia (FTD), and dementia with Lewy bodies (DLB), have become established practice and an effective and useful complement to other diagnostic methods in evaluating patients with progressive cognitive decline.
In Assessment of Inflammation and Infection
The diagnosis, severity and extent of aseptic inflammation or septic infection can be challenging, as there is no single test capable of achieving accurate diagnosis. The clinical use of 18F-FDG PET/CT imaging in the assessment of inflammation and infection is increasing worldwide.
Besides accumulation in malignant tissues, FDG also accumulates at sites of infection and inflammation due to increased glycolytic activity of inflammatory cells such as neutrophils, lymphocytes, and macrophages.
The first clinical application from this perspective was fever and inflammation of unknown origin (FUO/IUO), since FDG PET/CT was able to change the clinical management of patients in a high percentage of cases.
In the last 2 decades, more clinical applications have been investigated with excellent results in certain pathologies, such as large vessel vasculitis (LVV), spinal infections (SI), osteomyelitis and prosthetic joint infections, diabetic foot (DF), fungal infections (FI), tuberculosis (TBC), inflammatory bowel diseases (IBD), vascular graft infections (VGI), retroperitoneal fibrosis (RF), and COVID-19 infections.
The diagnosis, severity and extent of aseptic inflammation or septic infection can be challenging, as there is no single test capable of achieving accurate diagnosis. The clinical use of 18F-FDG PET/CT imaging in the assessment of inflammation and infection is increasing worldwide.
Besides accumulation in malignant tissues, FDG also accumulates at sites of infection and inflammation due to increased glycolytic activity of inflammatory cells such as neutrophils, lymphocytes, and macrophages.
The first clinical application from this perspective was fever and inflammation of unknown origin (FUO/IUO), since FDG PET/CT was able to change the clinical management of patients in a high percentage of cases.
In the last 2 decades, more clinical applications have been investigated with excellent results in certain pathologies, such as large vessel vasculitis (LVV), spinal infections (SI), osteomyelitis and prosthetic joint infections, diabetic foot (DF), fungal infections (FI), tuberculosis (TBC), inflammatory bowel diseases (IBD), vascular graft infections (VGI), retroperitoneal fibrosis (RF), and COVID-19 infections.
References
Zhuang H, Codreanu I. Growing applications of FDG PET-CT imaging in non-oncologic conditions. J Biomed Res. 2015 May;29(3):189-202.
Gholamrezanezhad A, Basques K, Batouli A, Matcuk G, Alavi A, Jadvar H. Clinical Nononcologic Applications of PET/CT and PET/MRI in Musculoskeletal, Orthopedic, and Rheumatologic Imaging. AJR Am J Roentgenol. 2018 Jun;210(6):W245-W263.
Gerhard Franz, Giancarlo Schiappacasse, Andrea Balcells, Stefan Guilof. Role of 18FDG PET/CT in non-malignant diseases. Revista Chilena de Radiología. Vol. 23 Nº 3, año 2017; 116-129.
Massimiliano Casali, Chiara Lauri, Corinna Altini et al. State of the art of 18F-FDG PET/CT application in inflammation and infection: a guide for image acquisition and interpretation. Clinical and Translational Imaging (2021) 9:299-339.
Zhuang H, Codreanu I. Growing applications of FDG PET-CT imaging in non-oncologic conditions. J Biomed Res. 2015 May;29(3):189-202.
Gholamrezanezhad A, Basques K, Batouli A, Matcuk G, Alavi A, Jadvar H. Clinical Nononcologic Applications of PET/CT and PET/MRI in Musculoskeletal, Orthopedic, and Rheumatologic Imaging. AJR Am J Roentgenol. 2018 Jun;210(6):W245-W263.
Gerhard Franz, Giancarlo Schiappacasse, Andrea Balcells, Stefan Guilof. Role of 18FDG PET/CT in non-malignant diseases. Revista Chilena de Radiología. Vol. 23 Nº 3, año 2017; 116-129.
Massimiliano Casali, Chiara Lauri, Corinna Altini et al. State of the art of 18F-FDG PET/CT application in inflammation and infection: a guide for image acquisition and interpretation. Clinical and Translational Imaging (2021) 9:299-339.