Evaluation of the right heart in pulmonary hypertension by positron emission tomography

Pulmonary hypertension (PH) is associated with a metabolic shift towards glycolysis in both the right ventricle and lungs. This results in increased glucose uptake to compensate for the lower energy yield of glycolysis, which creates a potential for 2-[18F] fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) to be a useful tool in the non-invasive evaluation of PH patient's right heart and pulmonary vasculary remoduling. We investigated the utility of PET for PH by comparing FDG-PET uptake in the right ventricle and lungs in 17 participants with Group I (IPAH) and CTEPH patients and 30 healthy controls All participants underwent gated FDG-PET scanning in the fasting state, right heart catheterization, ECHO, six-minute walk test (6MWT), and blood draw for NT-proBNP. 11 patients repeated FDG-PET after 6-month treatment. Right and left lung FDG (p= 0,004 and p= 0,006), right atrium FDG (p= 0,000) and right ventricle FDG (p= 0,000) were significantly increased compared with controls; while the FDG in left ventricle showed no difference. The patiens with functional class IV at the beginning has a significant increase in their right atrial (p = 0, 012) and right ventricular FDG compared with the other patients right atrial and ventricular FDG (p= 0,020). In a total of 11 patients who performed PET scans before and after 6 months of treatment, there is no significant difference between before and after FDG of right atrium, right ventricle and lungs, although the values are decreased. Right atrial FDG strongly correlated with right atrial pressure (r=0,5 p= 0,020) and right ventricular FDG (r=0,7 p=0,012) correlated with mean pulmonary arterial pressure. In conclusion; increased right atrial and ventricular FDG indicates increased pulmonary arterial pressure. That might be useful for right ventricul evaluation and also useful for detection of PHT and patients prognosis. Key words: İdiopathic pulmonary hypertension, chronic thromboembolic hypertension, positron emission tomography, right heart catheterization