Pulmonary Artery Diameter Measurement and Semiquantitative Visual Scoring with Q-SPECT-CT in Acute Pulmonary Embolism

Objective: To investigate whether pulmonary artery diameters obtained from lung perfusion single-photon emission computed tomography-computed tomography (SPECT-CT) images and semiquantitative visual scoring (SVS) could serve as predictors of chronic pulmonary thromboembolic disease (CPTED) in acute pulmonary embolism patients (APE). Study Design: Observational study. Place and Duration of the Study: Department of Nuclear Medicine, Samsun Provincial Health Directorate, Gazi State Hospital, Samsun, Turkey, from January 2016 to March 2021. Methodology: A total of 142 patients undergoing lung perfusion SPECT-CT were included in this study. Patients were classified as APE (+) (n=42) and APE (-) (n=100) based on laboratory and radiological findings, clinical diagnosis, and treatment protocol. Non-contrast CT images were used to determine the diameters (mm) of the main (MPA), right (RPA), and left (LPA) pulmonary arteries and the main pulmonary artery/aorta (PA/AO) ratio. All perfusion defects were scored using SVS for the PE (+) group. Seventeen patients with a diagnosis of CPTED were followed up. The scores and arterial diameters of recovered APE and follow-up patients were compared. Results: The mean diameters ( mm) of MPA, RPA, and LPA and PA/AO ratio were 29.74 +/- 5.51, 21.73 +/- 4.11, 22.74 +/- 4.16, and 0.83 +/- 0.16 in the APE (+) group and 26.18 +/- 4.99, 19.35 +/- 3.84, 19.49 +/- 4.15, and 0.77 +/- 0.15 in the APE (-) group, respectively (p<0.001). Mean MPA diameter (mm), total defect (TD), right visual defect (RVD), and PA/AO ratio were 31.67 +/- 15.65, 29.88 +/- 15.59, 17.65 +/- 10.51, and 0.91 +/- 0.18 in the CPTED group and 28.06 +/- 4.59, 18.92 +/- 13.30, 10.4 +/- 7.41, and 0.78 +/- 0.15 in the recovered APE group, respectively (p<0.05). Conclusion: Assessment of pulmonary artery diameter and PA/AO ratio may indicate APE, but TD and RVD scores may be predictive factors for CPTED when included in the assessment along with MPA dilatation and PA/AO ratio.