The hypodense filling defects within the pulmonary veins on computed tomography described as pulmonary vein sign (PVS) have been noted in acute pulmonary embolism and shown to be associated with poor prognosis. The venous flow abnormalities in chronic thromboembolic pulmonary hypertension (CTEPH), were evaluated in order to determine its usefulness in the computed tomography assessment of CTEPH.

This blinded retrospective study, analyzed the CT scans of 50 proximal CTEPH cases and three control groups: 50 pulmonary arterial hypertension, 50 non thromboembolic cohorts, and 50 acute pulmonary embolism. PVS was most prevalent in CTEPH. Compared with all controls, sensitivity and specificity of PVS for CTEPH is 78.0% and 85.3% versus 34.0% and 70.7% in acute pulmonary embolism, 8.0% and 62% in non thromboembolic and 2.0% and 60% in pulmonary arterial hypertension.

In conclusion, our study has shown that PVS on CTPA has higher sensitivity and specificity for CTEPH than the other control groups (acute PE, PAH, and nonthromboembolic). PVS is relatively easy to see on CTPA, as shown by the high concordance between the independent blinded observers with varying expertise levels in our study. Therefore, it can be used as an aide‐memoire in the CTPA interpretation of thromboembolic disease and pulmonary hypertension.