Assessment of Valvular Calcification and Inflammation by Positron Emission Tomography in Patients With Aortic Stenosis

OBJECTIVES: The pathophysiology of aortic stenosis is incompletely understood and the relative contributions of valvular calcification and inflammation to disease progression are unknown.

METHODS: Patients with aortic sclerosis and mild, moderate and severe stenosis were prospectively compared to age and sex-matched control subjects. Aortic valve severity was determined by echocardiography. Calcification and inflammation in the aortic valve were assessed by sodium 18-fluoride (18F-NaF) and 18-fluorodeoxyglucose (18F-FDG) uptake using positron emission tomography. One hundred and twenty one subjects (20 controls; 20 aortic sclerosis; 25 mild, 33 moderate and 23 severe aortic stenosis) were administered both 18F-NaF and 18F-FDG.

RESULTS: Quantification of tracer uptake within the valve demonstrated excellent inter-observer repeatability with no fixed or proportional biases and limits of agreement of ±0.21 (18F-NaF) and ±0.13 (18F-FDG) for maximum tissue-to-background ratios (TBR). Activity of both tracers was higher in patients with aortic stenosis than control subjects (18F-NaF:2.87±0.82 vs 1.55±0.17; 18F-FDG: 1.58±0.21 vs 1.30±0.13; both P1.97) and 35% increased 18F-FDG (>1.63) uptake. A weak correlation between the activities of these tracers was observed (r(2)= 0.174, P

CONCLUSIONS: Positron emission tomography is a novel, feasible and repeatable approach to thee valuation of valvular calcification and inflammation in patients with aortic stenosis. The frequency and magnitude of increased tracer activity correlates with disease severity, and is strongest for 18F-NaF. 

PMID: 22090163

Posted in Computed Tomography, Nuclear Imaging and tagged , , , .

One Comment

  1. Very interesting paper! Two different radiotracers were used in a group of patients with different severity of disease.

    From the authors: “Our data have clearly established that this technique is both feasible and repeatable, indicating that these tracers may prove to be useful biomarkers of disease activity. Furthermore, we have demonstrated that 18F-fluorodeoxyglucose and 18F-sodium fluoride activity increase with progressive disease severity. However, uptake of 18F-sodium fluoride appears to predominate in both the early and latter stages of the disease. This may explain the disappointing effects of statin therapy in this condition and indicates that calcification might represent a better target for novel therapeutic interventions.” Interesting!

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