The diagnostic value of spectral CT plain scan after direct lymphangiography in chylothorax as an applicable tool.

Background: The difficulty in the diagnosis of chylothorax lies mainly in the fine structure of the lymphatic system, and the rupture of microscopic, branched lymphatic vessels which cannot be accurately diagnosed, and spectral computed tomography (CT) scanning can fill the gaps in the diagnosis of chylothorax in terms of the structure of the lymphatic system and the analysis of material composition. The study aims to elucidate the value of spectral CT plain scan after direct lymphangiography (DLG) in the diagnosis of chylothorax. Methods: From January 2018 to December 2023, we retrospectively recruited 59 patients with clinically confirmed diagnosis of chylothorax, and all patients underwent spectral CT after DLG scanning to observe the abnormalities of lymphatic vessels and the CT findings of other thoracic abnormalities, including abnormal contrast deposition, abnormal changes in the lungs, pleura, thoracic cavity, and mediastinum. Results: In all the 59 patients with chylothorax, abnormal contrast deposition was seen on spectral CT plain scan after DLG, and could be seen simultaneously in different areas of the superior mediastinum, the mediastinum and both sides of the mediastinum. In terms of anatomical sites, the location of abnormal contrast agent deposition was most common in the left venous angle. And multiple abnormalities in the lungs, the pleura, and the mediastinum were seen. Conclusions: Spectral CT plain scan after DLG is valuable for the diagnosis of chylothorax. Abnormal distribution of contrast in the lungs, lymphatic ducts and lymphatic trunks in spectral CT plain scan after DLG is an important manifestation of chylothorax, suggesting abnormal distribution and severity of the thoracic organs, lymphatic ducts and lymphatic trunks, and its imaging findings provide a basis for the clinical diagnosis and treatment of the disease.