Application of CT Lymphangiography in the Diagnosiis of Primary Pulmonary Lymphedema

Objective: To explore the clinical value of CT lymphangiography in diagnosing primary pulmonary lymphedema. Methods: 52 patients who were diagnosed by clinical, imaging and pathology as primary pulmonary lymphedema were analyzed retrospectively. All patients underwent CT lymphangiography. Two experienced radiologists carried out double-blind film reading of the CT lymphangiography manifestations, and observed the abnormal perfomance of lymphatic vessels in the chest as well as CT signs of other chest diseases.Results: CT lymphangiography showed contrast agent abnormity deposited in all 52 patients: the end of thoracic duct was found in 38 cases (73.1%), mediastinum in 34 cases (65.4%), hilar in 22 cases (42.3%), pleura in 18 cases (34.6%), pericardium in 15 cases (28.8%), diaphragm in 5 cases (9.6%), hepatic hilum in 9 cases (17.3%), pancreas in 5 cases (9.6%), retroperitoneum in 12 cases (23.1%). Abnormal CT changes including: (1) alveolar nodule-like ground glass opacity in 19 cases (36.5%), patchy ground glass opacity in 23 cases (44.2%), atelectasis in 11 cases (21.2%), pulmonary nodules in 3 cases (5.8%). (2) the thickening of bronchovascular bundle in 43 cases (82.7%), the thickening of interlobular septum in 43 cases (82.7%), the thickening of intralobular interstitium in 4 cases (7.7%), frog-spawn sign in 7 cases (13.5%). (3) abnormal mediastinum changes in 34 cases (65.4%). (4) other chest CT abnormalities including: the crazy-paving sign in 2 cases (3.8%), pleural effusion in 18 cases (34.6%), pericardial effusion in 18 case (34.6%). Conclusion: CT lymphangiography can indirectly predict the abnormality of lymphatics and the presence or absence of lymphatic reflux by showing the abnormal deposition and distribution of contrast agents, and thus can provide valuable imaging basis for the diagnosis and treatment of primary pulmonary lymphedema.