What is the meaning of LGE in right ventricle insertion points in pulmonary arterial hypertension? – a PET/MRI study

Abstract

Presence of late gadolinium enhancement (LGE) in right ventricle insertion points (RVIPs) has been found in majority of pulmonary arterial hypertension (PAH) patients and is often recognized as evidence of myocardial fibrosis. The aim of the study was to evaluate the relationship between LGE mass and myocardium metabolic activity in RVIPs using PET/MRI imaging. Twenty-eight clinically stable PAH patients had PET/MRI scans during baseline and 2-year follow up (FU) visits. Fluorodeoxyglucose cardiac uptake was assessed in the area of LGE (SUVRVIPS). Clinical end-point (CEP) was defined as death or clinical deterioration. Mean LGE mass in RVIPs was 6.67±4.41 g and mean SUVRVIPS was 7.28±5.36. FU values were 8.01±7.75 g (p=0.27) and 5.81±3.16 (p=0.16), respectively. Decrease of SUVRVIPS was observed in 70% (n=14) cases. No statistically significant correlation was found between LGE mass and SUVRVIPS (in both baseline and FU scans). PAH therapy have an impact on both LGE mass and FDG uptake in cardiac local tissue changes. Lack of reverse correlation between those two parameters suggests that LGE is not less metabolically active than the surrounding myocardium and hence it is unlikely to be simple fibrotic change, however this finding requires further studies. Trial Registration: Clinical Trials.gov; NCT03688698, 09/26/2018, retrospectively registered; Protocol ID: 2017/25/N/NZ5/02689l https://clinicaltrials.gov/ct2/show/NCT03688698