Original Investigation| Volume 29, ISSUE 11, e229-e239, November 2022

Heterogeneity of Lung Density in Patients With Chronic Thromboembolic Pulmonary Hypertension (CTEPH)

Published:April 22, 2022DOI:

      Rationale and Objectives

      Pulmonary endarterectomy (PEA) is one of the most effective treatments for chronic thromboembolic pulmonary hypertension (CTEPH). Right heart catheterization (RHC) is the gold standard assessment for pulmonary circulatory dynamics. However, computed tomography (CT) is less invasive than RHC and can elucidate some of the morphological changes caused by thromboembolism. We hypothesized that CT could facilitate the evaluation of heterogeneous pulmonary perfusion. This study investigated whether CT imaging features reflect the disease severity and changes in pulmonary circulatory dynamics in patients with CTEPH before and after PEA.

      Materials and Methods

      This retrospective study included 58 patients with CTEPH who underwent PEA. Pre-PEA and post-PEA CT images were assessed for heterogeneity using CT texture analysis (CTTA). The CT parameters were compared with the results of the RHC and other clinical indices and analyzed with receiver operating characteristic curves analysis for patients with and without residual pulmonary hypertension (PH) (post-PEA mean pulmonary artery pressure ≥ 25 mmHg).


      CT measurements reflecting heterogeneity were significantly correlated with mean pulmonary artery pressure. Kurtosis, skewness, and uniformity were significantly lower, and entropy was significantly higher in patients with residual PH than patients without residual PH. Area under the curve values of pre-PEA and post-PEA entropy between patients with and without residual PH were 0.71 (95% confidence interval 0.57–0.84) and 0.75 (0.63–0.88), respectively.


      Heterogeneity of lung density might reflect pulmonary circulatory dynamics, and CTTA for heterogeneity could be a less invasive technique for evaluation of changes in pulmonary circulatory dynamics in patients with CTEPH undergoing PEA.

      Key Words


      AaDO2 (alveolar-arterial oxygen difference), APTE (acute pulmonary thromboembolism), CI (cardiac index), CO (cardiac output), CSA < 5 (cross-sectional area of small pulmonary vessels less than 5 mm2 on CT images), CTEPH (chronic thromboembolic pulmonary hypertension), CTTA (CT texture analysis), DLCO (diffusing capacity for carbon monoxide), HU (Hounsfield unit), mPAP (mean pulmonary artery pressure), PaCO2 (partial pressure of carbon dioxide in pulmonary arterial blood), PaO2 (partial pressure of oxygen in pulmonary arterial blood), PAWP (pulmonary artery wedge pressure), PE (pulmonary embolism), PEA (pulmonary endarterectomy), PH (pulmonary hypertension), PVR (pulmonary vascular resistance), RHC (right heart catheterization), ROI (region of interest), sPAP (systolic pulmonary artery pressure), TLA (total lung area %), CSA < 5 (the percentages of CSA < 5)
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