Researchers from the University of Edinburgh, Scotland have demonstrated early detection of aortic stenosis using positron emission tomography (PET) scanning and chemical tracers. The researchers used two different tracers as markers of vascular inflammation (18-fluorodeoxyglucose) and calcification (sodium 18-fluoride) in the valves of patients with aortic stenosis. The study, which was published online in the journal Circulation, aimed to assess the feasibility and reproducibility of the new PET imaging approach for the diagnosis of various degrees of aortic stenosis. The background to the study is explained in the video by Dr. Mark Dweck, one of the lead investigators of the study.
From the paper’s abstract:
Methods and Results—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. 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
The PET imaging technique also demonstrated that vascular inflammation played a significant role in the earlier stages of aortic stenosis while subsequent narrowing in the later stages was due to calcification around the valve. Consequently the researchers have proposed that future potential medical therapies for aortic stenosis should address this problem.