Role of PET imaging in evaluating right ventricular function and prognosis in pulmonary hypertension

Pulmonary Hypertension (PH) is a complex pathophysiological condition associated with high morbidity and mortality. Regardless of etiology, Right Ventricular (RV) dysfunction remains a major determinant of prognosis. This integrative review summarizes the current evidence on the role of Positron Emission Tomography (PET) imaging in evaluating disease severity and exploring associations with clinical outcomes in PH, emphasizing how different tracers capture the biological processes underlying RV dysfunction.

A systematic literature search was performed using PubMed, EMBASE, Scopus, and Web of Science, identifying 35 eligible studies. The review discusses PET tracers, technical aspects of image processing and quantification techniques, and metrics correlated with physiological measures, highlighting their diagnostic and prognostic implications.

PET tracers used for RV assessment in PH include [¹³N]NH₃, [¹¹C]acetate, [¹⁸F]FDG, [⁶⁸Ga]FAPI, and [¹⁸F]LMI1195, with [¹⁸F]FDG being the most widely employed. Quantification predominantly relies on the standardized uptake value (SUV) and kinetic modeling parameters. Common metrics include SUV_mean, SUV_max, and the RV/Left Ventricle (LV) SUV ratio (SUV_RV/LV), which improves inter-patient comparability. However, variability in acquisition and analysis methods limits cross-study comparability. Some studies report SUV_RV/LV thresholds above 1.0 as predictors of adverse outcomes, including increased mortality, greater RV dysfunction, and disease severity.

PET imaging represents a valuable, noninvasive modality for evaluating RV function and prognosis in PH. Elevated SUV and SUV_RV/LV have been reported to be associated with adverse outcomes in several studies. However, methodological heterogeneity limits cross-study comparability. Future studies should aim to standardize acquisition and quantification protocols and include larger prospective studies.