Prediction of coronary artery calcium progression by FDG uptake of large arteries in asymptomatic individuals

Nuclear medicine in the assessment and prevention of cancer therapy-related cardiotoxicity: prospects and proposal of use by the European Association of Nuclear Medicine (EANM)

Cardiotoxicity may present as (pulmonary) hypertension, acute and chronic coronary syndromes, venous thromboembolism, cardiomyopathies/heart failure, arrhythmia, valvular heart disease, peripheral arterial disease, and myocarditis. Many of these disease entities can be diagnosed by established cardiovascular diagnostic pathways. Nuclear medicine, however, has proven promising in the diagnosis of cardiomyopathies/heart failure, and peri- and myocarditis as well as arterial inflammation. This article first outlines the spectrum of cardiotoxic cancer therapies and the potential side effects. This will be complemented by the definition of cardiotoxicity using non-nuclear cardiovascular imaging (echocardiography, CMR) and biomarkers. Available nuclear imaging techniques are then presented and specific suggestions are made for their application and potential role in the diagnosis of cardiotoxicity.

Advances in positron emission tomography tracers related to vascular calcification

Microcalcification, a type of vascular calcification, increases the instability of plaque and easily leads to acute clinical events. Positron emission tomography (PET) is a new examination technology with significant advantages in identifying vascular calcification, especially microcalcification. The use of the ¹⁸F-NaF is undoubtedly the benchmark, and other PET tracers related to vascular calcification are also currently in development. Despite all this, a large number of studies are still needed to further clarify the specific mechanisms and characteristics. This review aimed at providing a summary of the application and progress of different PET tracers and also the future development direction.

KSNM60 in Cardiology: Regrowth After a Long Pause

The Korean Society of Nuclear Medicine (KSNM) is celebrating its 60th anniversary in honor of the nuclear medicine professionals who have dedicated their efforts towards research, academics, and the more comprehensive clinical applications and uses of nuclear imaging modalities. Nuclear cardiology in Korea was at its prime time in the 1990s, but its growth was interrupted by a long pause. Despite the academic and practical challenges, nuclear cardiology in Korea now meets the second leap, attributed to the growth in molecular imaging tailored for many non-coronary diseases and the genuine values of nuclear myocardial perfusion imaging. In this review, we describe the trends, achievements, challenges, and perspectives of nuclear cardiology throughout the 60-year history of the KSNM.

Imaging Atherosclerosis by PET, With Emphasis on the Role of FDG and NaF as Potential Biomarkers for This Disorder

Molecular imaging has emerged in the past few decades as a novel means to investigate atherosclerosis. From a pathophysiological perspective, atherosclerosis is characterized by microscopic inflammation and microcalcification that precede the characteristic plaque buildup in arterial walls detected by traditional assessment methods, including anatomic imaging modalities. These processes of inflammation and microcalcification are, therefore, prime targets for molecular detection of atherosclerotic disease burden. Imaging with positron emission tomography/computed tomography (PET/CT) using 18F-fluorodeoxyglucose (FDG) and 18F-sodium fluoride (NaF) can non-invasively assess arterial inflammation and microcalcification, respectively. FDG uptake reflects glucose metabolism, which is particularly increased in atherosclerotic plaques retaining macrophages and undergoing hypoxic stress. By contrast, NaF uptake reflects the exchange of hydroxyl groups of hydroxyapatite crystals for fluoride producing fluorapatite, a key biochemical step in calcification of atherosclerotic plaque. Here we review the existing literature on FDG and NaF imaging and their respective values in investigating the progression of atherosclerotic disease. Based on the large volume of data that have been introduced to the literature and discussed in this review, it is clear that PET imaging will have a major role to play in assessing atherosclerosis in the major and coronary arteries. However, it is difficult to draw definitive conclusions on the potential role of FDG in investigating atherosclerosis given the vast number of studies with different designs, image acquisition methods, analyses, and interpretations. Our experience in this domain of research has suggested that NaF may be the tool of choice over FDG in assessing atherosclerosis, especially in the setting of coronary artery disease (CAD). Specifically, global NaF assessment appears to be superior in detecting plaques in tissues with high background FDG activity, such as the coronary arteries.

Arterial Inflammation Detected With 18 F-Fluorodeoxyglucose-Positron Emission Tomography in Rheumatoid Arthritis

OBJECTIVE

In addition to traditional risk factors, excess cardiovascular disease (CVD) in rheumatoid arthritis (RA) is attributed to enhanced vascular and/or systemic inflammation. In several small studies using ¹⁸ F-fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸ F-FDG-PET/CT) to directly assess vascular inflammation, FDG uptake was higher in RA patients than in controls. Using a substantially larger sample of RA patients, we sought to identify RA disease characteristics independently associated with vascular FDG uptake.

METHODS

RA patients underwent cardiac FDG-PET/CT, with aortic inflammation assessed by quantification of FDG uptake in the ascending aorta, calculated as the mean and maximum (max) standardized uptake value (SUV) of the entire ascending aorta and of its most diseased segment (SUV MDS). Univariate and multivariable regression models were constructed to model the associations of patient characteristics with aortic FDG uptake.

RESULTS

Ninety-one RA patients were scanned. In multivariable models, in addition to the independent associations of hypertension and body mass index with increased aortic FDG uptake, the prevalence of rheumatoid nodules correlated with the SUV mean and SUV MDS mean measures, while anti-cyclic citrullinated peptide (anti-CCP) antibodies correlated inversely with these measures and with the SUV max and SUV MDS max (P < 0.05). A significant association of RA disease activity with aortic FDG uptake was observed but was restricted to anti-CCP seropositivity.

CONCLUSION

Traditional CV risk factors and RA disease characteristics (rheumatoid nodules and the Disease Activity Score in 28 joints using the C-reactive protein level in anti-CCP antibody-positive individuals) were independently associated with ascending aortic FDG uptake in RA patients without clinical CVD.

Metabolic and Molecular Imaging of Atherosclerosis and Venous Thromboembolism

Metabolic and molecular imaging continues to advance our understanding of vascular disease pathophysiology. At present, ¹⁸F-FDG PET imaging is the most widely used clinical tool for metabolic and molecular imaging of atherosclerosis. However, novel nuclear tracers and intravascular optical near-infrared fluorescence imaging catheters are emerging to assess new biologic targets in vivo and in coronary arteries. This review highlights current metabolic and molecular imaging clinical and near-clinical applications within atherosclerosis and venous thromboembolism, and explores the potential for metabolic and molecular imaging to affect patient-level risk prediction and disease treatment.