Abstract： Objective:To investigate 18F-FDG PET/CT imaging features of pneumonic-type pulmonary invasive mucinous adenocarcinoma(PPIMA).Methods:The imaging data of 20 patients with PPIMA confirmed by surgery and biopsy were retro-spectively analyzed.All patients underwent 18F-FDG PET/CT imaging to observe the lesion morphology,density,signs around and inside the lesion,metabolism and distant metastasis.Results:Among the 20 cases of PPIMA,2 cases(10.0％)had single flaky solid shadow,and 18 cases(90.0％)had multiform and multifocal distribution of solid shadow with ground glass shadow and nodule shadow.Abnormal air bronchial sign was found in 16 cases(80.0％).Cavity and cavum were found in 12 cases(60％).There were 8 cases(40％)with peri-focal ground glass density.The adjacent interlobar fissure was enlarged in 11 cases(55.0％).Intrapulmonary metastasis occurred in 4 cases(20％).The internal density of the solid lesions was not uniform,and CT value was(27.2±6.8)HU.Metabolism varied,SUVmax 5.2±1.9.There was a significant correlation between SUVmax and CT values(r=0.765,P=0.000).Conclusion:18F-FDG PET/CT of PPIMA has certain characteristics,which is helpful for early diagnosis and staging of PPIMA.