Abstract： Objective:To investigate the clinical manifestations and 18F-FDG PET/CT imaging features of hilar tumor pulmonary infarction. Methods:From July 2016 to June 2021, 49 patients (40 males, 9 females; age 32-81 years) with hilar tumor pulmonary infarction who underwent PET/CT and enhanced CT in the second Hospital of Shandong University and Shandong Cancer Hospital and Institute, Shandong First Medical University were retrospectively enrolled. All patients were diagnosed by imaging follow-up or pathology. Clinical features and 18F-FDG PET/CT imaging features were analyzed. Results:A total of 108 infarcts were found in 49 patients by 18F-FDG PET/CT. Small cell carcinoma was the most common hilar tumor (67.35%, 33/49). The most common clinical manifestations of hilar tumor pulmonary infarction were cough (69.39%, 34/49) and hemoptysis (34.69%, 17/49). Pulmonary infarction was mainly multiple (69.39%, 34/49), and multiple lung lobes might be involved. The CT morphology of infarcts was wedge-shaped (46.30%, 50/108) or patchy (53.70%, 58/108), and the density was mainly bubble consolidation (61.11%, 66/108). There were 91 (84.26%, 91/108) infarcts showing FDG hypermetabolism, with the SUV max of 1.48-6.62, and the hypermetabolism mode was rim sign (36.11%, 39/108) or heterogeneous hypermetabolism (48.15%, 52/108). Nineteen patients (38.78%, 19/49) were complicated with pulmonary vein involvement, and 26 patients (53.06%, 26/49) had ipsilateral pleural effusion. Conclusions:Hilar tumor pulmonary infarction is characterized by cough. It is helpful for the diagnosis of hilar tumor pulmonary infarction in patients with hilar tumor when wedge-shaped, bubble consolidation, rim sign and heterogeneous hypermetabolism lesions are found in 18F-FDG PET/CT images.