Abstract
BACKGROUND: Because the myocardium thickness and blood flow of the right ventricular (RV) are lower than those of the left ventricle, it is challenging to perceive the RV myocardium in normal individuals. This study aimed to measure the myocardial perfusion in the RV (myocardial blood flow [MBF](RV), myocardial flow reserve [MFR](RV)) from 13N-ammonia PET images and investigate the associations between the MBF(RV) and MFR(RV) in patients with and without coronary artery disease (CAD) in the right coronary artery (RCA) region. A total 121 MBF(RV) and MFR(RV) were retrospectively measured from PET images by referring to the radioactivity and clinical blood flow values of the left ventricle. Adenosine-stressed and resting MBF(RV) and MFR(RV) were statistically compared among patients with RCA-MFR < 2.0 (group 1 [n = 61]), without RCA-MFR < 2.0 but with reduced MBF (group 2 [n = 16]), and without MFR < 2.0 (group 3 [n = 44]) using one-way analysis of variance with Tukey or Dunn post hoc analyses. RESULTS: Stress MBF(RV) was lower in Group 1 than in Group 3, whereas resting MBF(RV) was higher in Group 1 than in Group 3. MFR(RV) gradually decreased from Group 3 to Group 1. CONCLUSIONS: This study demonstrated the potential clinical applications of RV myocardial perfusion imaging using PET data. Our results highlight the importance of evaluating the MBF(RV), particularly in patients with CAD. In CAD cases, the MFR(RV) was significantly reduced, with a more pronounced decrease, reflecting the severity of the disease. Additionally, increased resting MBF(RV) in patients with CAD may indicate compensatory mechanisms or microcirculatory disorders. These findings provide a foundation for further exploration of MBF(RV) and support the development of robust automated processing techniques to enhance clinical applicability.