Abstract 18459: CT-guided Planar Imaging for the Assessment of Right Ventricular Myocardial Perfusion: a Novel, Noninvasive Monitoring Tool for Patients With Pulmonary Hypertension

Introduction: In patients with pulmonary hypertension (PH), right ventricular (RV) dysfunction as a consequence of increased RV pressure may result in RV enlargement and hypertrophy, which also increases the RV myocardial perfusion. Hypothesis: We assessed the hypothesis that RV myocardial perfusion detected by planar thallium-201 (201Tl) imaging is useful for quantitative evaluation for RV dysfunction in PH patients. Method: The study groups included 16 PH patients with chronic thromboembolic pulmonary hypertension (CTEPH) and 24 healthy controls. All subjects underwent myocardial perfusion SPECT/CT. Cardiac CT was used to obtain the optimal angle to differentiate the RV from the left ventricle (LV). Forty minutes after intravenously administration of 111 MBq of 201Tl, planar acquisition from the optimal angle was performed. In the planar image, we measured the total counts of 201Tl in the RV and LV. The relative count of the RV to LV (HR/HL) was calculated as RV myocardial perfusion indicator for this study. Mean pulmonary artery pressure (mPAP) by cardiac catheterization was obtained in all PH patients to estimate the severity. Results: HR/HL was significantly elevated in the PH group compared with control (0.57 ± 0.13 vs. 0.36 ± 0.07, p Conclusion: Relative RV accumulation in CT-guided 201Tl planar imaging by SPECT/CT was associated with the severity of PH in CTEPH patients and decreased after surgical treatment of CTEPH in parallel with the reduction of mPAP. This method may represent a novel, noninvasive monitoring tool for PH patients.