[18F]Sodium Fluoride PET has the potential to identify active formation of calcinosis cutis in limited cutaneous systemic sclerosis.

OBJECTIVES: Calcinosis cutis affects 20-40% of patients with systemic sclerosis (SSc). When calcinosis cutis becomes clinically apparent, it is irreversible in most cases. Detection of active calcification formation might allow early disease-modifying interventions. We assessed the feasibility of visualizing active calcifications using [18F]Sodium Fluoride ([18F]NaF) PET/low-dose CT (LDCT) in SSc patients with calcinosis cutis. METHODS: In this cross-sectional, observational pilot study patients underwent a whole body [18F]NaF PET/LDCT. All patients met the 2013 ACR/EULAR SSc criteria and had clinically detectable calcinosis cutis. (Sub)cutaneous calcifications were described by three investigators. RESULTS: Nine female patients were included (median age 59.0 years [IQR 51.5-70.5]). [18F]NaF uptake was mostly visible in the fingers (n=7) and knees (n=5). [18F]NaF PET showed calcifications in the fingers of 3 patients where calcifications were undetected on LDCT and in the clinic. Ninety-seven percent of [18F]NaF positive lesions was visible on LDCT. Of all lesions visible on LDCT, 70% was also visible on [18F]NaF PET. CONCLUSION: Imaging of active calcifications in SSc is feasible using [18F]NaF PET/LDCT. Seventy percent of calcifications on LDCT were [18F]NaF PET positive. Although these findings require replication, [18F]NaF PET/LDCT may detect active calcification formation, being potentially suitable for early disease-modifying interventions.

The AGE Reader: A non-invasive method to assess long-term tissue damage.

AIMS: Advanced glycation endproducts (AGEs) are sugar-modified adducts which arise during non-enzymatic glycoxidative stress. These compounds may become systemically elevated in disease states, and accumulate in tissue, especially on long-lived proteins. AGEs have been implicated in various acute, and chronic diseases, stressing the need for reliable and comprehensive measuring techniques. Measurement of AGEs in tissue such as skin requires invasive skin biopsies. The AGE Reader has been developed to assess skin autofluorescence (SAF) non-invasively using the fluorescent properties of several AGEs. RESULTS/CONCLUSION: Various studies have shown that SAF is a useful marker of disease processes associated with oxidative stress. It is prospectively associated with the development of cardiovascular events in patients with diabetes, renal or cardiovascular disease, and it predicts diabetes, cardiovascular disease, and mortality in the general population. However, when measuring SAF in individual subjects, several factors may limit the reliability of the measurement. These include endogenous factors present in the skin that absorb emission light such as melanin in dark-skinned subjects, but also factors that lead to temporal changes in SAF such as acute diseases and strenuous physical exercise associated with glycoxidative stress. Also, exogenous factors could potentially influence SAF levels inadvertently such as nutrition, and for example the application of skin care products. This review will address the AGE Reader functionality and the endogenous, and exogenous factors which potentially influence the SAF assessment in individual subjects.