In search of the vulnerable patient or the vulnerable plaque: 18F-sodium fluoride positron emission tomography for cardiovascular risk stratification

Abstract

Cardiovascular disease (CVD) remains a leading cause of death. Preventative therapies that reduce CVD are most effective when targeted to individuals at high risk. Current risk stratification tools have only modest prognostic capabilities, resulting in over-treatment of low-risk individuals and under-treatment of high-risk individuals. Improved methods of CVD risk stratification are required. Molecular imaging offers a novel approach to CVD risk stratification. In particular, F-sodium fluoride (F-NaF) positron emission tomography (PET) has shown promise in the detection of both high-risk atherosclerotic plaque features and vascular calcification activity, which predicts future development of new vascular calcium deposits. The rate of change of coronary calcium scores, measured by serial computed tomography scans over a 2-year period, is a strong predictor of CVD risk. Vascular calcification activity, as measured with F-NaF PET, has the potential to provide prognostic information similar to consecutive coronary calcium scoring, with a single-time-point convenience. However, owing to the rapid motion and small size of the coronary arteries, new solutions are required to address the traditional limitations of PET imaging. Two different methods of coronary PET analysis have been independently proposed and here we compare their respective strengths, weaknesses, and the potential for clinical translation.

Determinants of 18F-NaF uptake in femoral arteries in patients with type 2 diabetes mellitus

“…5 Sodium 18F-fluoride ( 18 F-NaF) PET/CT is a novel imaging technique that can visualize smaller calcifications. [6][7][8][9][10] In the femoral arteries, 18 F-NaF PET can visualize ongoing (medial and intimal) calcification. 11 In the coronaries 18 F-NaF PET is associated with high risk plaque features and plaque rupture.…”

Iterative reconstruction incorporating background correction improves quantification of [18F]-NaF PET/CT images of patients with abdominal aortic aneurysm

“…14,15 The use of [ 18 F]-FDG PET for AAA imaging is therefore limited, with potential confounding factors and lack of specificity, thereby raising concerns about its future clinical use in predicting potential AAA expansion and risk of rupture. 14,15 Nevertheless, an alternative PET radiotracer, [ 18 F]-NaF, is currently being explored as a marker for microcalcification in the cardiovascular system [16][17][18] and has been used to investigate coronary atherosclerosis, 19,20 abdominal atherosclerosis, 21 aortic stenosis 22,23 and AAA diseases. 24 Preliminary investigation 24 shows that this tracer is promising for improved prediction of AAA disease progression, and may therefore facilitate early intervention for those at higher risk of rupture.…”

Coronary artery calcification: More than meets the eye

“…Although not ready for prime time, 18 F-NaF PET imaging can potentially help risk stratify these patients. 29 The absence of 18 F-NaF PET signal in calcified lesions likely indicates stable plaque. Further validation with large multi-center randomized trials, however, are needed to determine the negative predictive value of 18 F-NaF PET imaging.…”