PT - JOURNAL ARTICLE AU - Yuka Ochi AU - Yoshinori Ito AU - Rina Murayama AU - Ikeda Haruna AU - MIka Tamura AU - Yoshinori Tsutsumi AU - Katsuhiko Kato TI - Comparison of pulmonary perfusion index using<sup>99m</sup>Tc-MAA SPECTand evaluation indices obtained from right-sided heart catheterization in chronic thromboembolic pulmonary hypertension DP - 2020 May 01 TA - Journal of Nuclear Medicine PG - 3087--3087 VI - 61 IP - supplement 1 4099 - http://jnm.snmjournals.org/content/61/supplement_1/3087.short 4100 - http://jnm.snmjournals.org/content/61/supplement_1/3087.full SO - J Nucl Med2020 May 01; 61 AB - 3087Objectives: Right-sided heart catheterization and ventilation/perfusion lung scanning are performed to diagnose chronic thromboembolic pulmonary hypertension (CTEPH). The degree of pulmonary hypertension is important to assess the severity of CTEPH. Typically, right-sided heart catheterization is considered as an essential test since it facilitates an accurate assessment of the clinical condition and severity of the disease; however, it is highly invasive. Therefore, diagnosing seriously ill patients via indices obtained from the less invasive SPECT-CT examination modalities would be considerably beneficial. Here, we calculated the pulmonary perfusion index from the SPECT-CT images of pulmonary perfusion scintigraphy using 99mTc-MAA and X-ray CT images, and explored the presence of a correlation between the pulmonary perfusion index and several evaluation indices (mean pulmonary arterial pressure, pulmonary vascular resistance, and cardiac index) acquired from right-sided heart catheterization. Methods: We selected 27 patients with a confirmed diagnosis of CTEPH. We set a region of interest in the range above the threshold using an appropriate analysis software on a 99mTc-MAA SPECT image. The volume of the set region of interest was used as the perfusion lung volume. We subsequently measured two types of total lung volume, using another analysis software, from CT images obtained by SPECT-CT under free breathing and X-ray CT images acquired while the patients were instructed to hold their breath. The perfusion lung volume was divided by the total lung volume, which yielded the two variations of the pulmonary perfusion index. We explored correlations between the two types of pulmonary perfusion indices and evaluation indices obtained from right-sided heart catheterization. Results and Discussion There were no significant correlations between the pulmonary perfusion indices obtained from 99mTc-MAA SPECT-CT images and evaluation indices obtained from right-sided heart catheterization. Evaluation indices associated with the right-sided heart catheterization represented the degree of pulmonary hypertension, while the pulmonary perfusion index obtained from 99mTc-MAA SPECT-CT images represented a degree of pulmonary embolism. Therefore, there were supposed to be no correlations between them. Conclusions: There were no significant correlations between the pulmonary perfusion indices obtained from 99mTc-MAA SPECT-CT images and the evaluation indices obtained from right-sided heart catheterization.