Table 1 Clinical advantages and disadvantages of ¹⁸ F-FDG PET scanning in PAH

Advantages

• Commonly available in many hospitals

• Easy to manufacture and easy to transport

• Mechanisms which predict an altered tracer activity in PAH have been relatively well studied

Disadvantages

• No consensus exists on appropriate patient preparation prior to imaging (e.g. overnight fasting and glucose loading), leading to inconsistencies in results between centers

• Lung and right ventricular ¹⁸F-FDG uptake does not correlate with disease severity or survival

• Lung and right ventricular ¹⁸F-FDG uptake rapidly normalize upon PAH treatment, questioning the utility of ¹⁸F-FDG PET in the follow-up of patients

• Corrections for lung density have not been performed

• Increased FDG uptake in the heart could either reflect an increase in

• After load or a direct, after load-independent, change in energy metabolism. It is not possible to determine the relative contributions of both processes