Parenchymal opacities associated with pulmonary embolism

The characteristics of parenchymal opacities associated with acute and chronic pulmonary embolism may differ. The aim of this study is to determine the characteristics of parenchymal opacities associated with acute and chronic pulmonary embolism.

Patients with pleural-based parenchymal opacities whose PE was confirmed by CTPA at a medical center between 2013 and 2019 were incorporated into the study. Follow-up CT was detected in 43 of 80 patients with parenchymal opacity. Patients were divided into acute and chronic pulmonary embolism according to CT features.

In total, 84 peripheral parenchymal opacities were found in 43 patients, of which 59 infarctions in 35 patients (70.2 %) could be confirmed at follow-up, with similar sequelae rates in acute and chronic cases. Scar tissue developed in 33.3 % (3/9) of ground-glass opacities, 80.4 % (37/46) of consolidations, and 65.5 % (19/29) of mixed consolidations. Clinical (dyspnea, chest pain, syncope/presyncope, cough, hemoptysis), laboratory (creatinine, proBNP, HTC, CRP, oxygen saturation, except D-dimer) and cardiac CT findings (such as the RV/LV diameter ratio ≥1 %, pulmonary artery diameter) were similar in both groups.

More than two-thirds of pulmonary embolism-related opacities develop into infarction with scar tissue, regardless of whether the pulmonary embolism is acute or chronic. According to the morphological features of opacities, scar tissue develops at different frequencies, most frequently in consolidation. Opacities associated with chronic pulmonary embolism are as important as opacities in acute cases and both require long-term follow-up.