Abstract:
Objective To analyze the image features of lung carcinoid tumor during 18F-fluorodeoxyglucose (18F-FDG) PET/CT.
Methods The 18F-FDG PET/CT image manifestations of 16 patients with lung carcinoma, as confirmed by pathology, who underwent 18F-FDG PET/CT pretreatment from March 2009 to August 2018 were reviewed. The location, shape, whole-body metastasis, and metabolism of the lesions were observed. The 16 cases included 6 males and 10 females aged 43−78 years old, with a median age of 65 years. The cases included 5 typical carcinoma (TC) and 11 atypical carcinoma (AC). The statistical difference in maximum standardized uptake value (SUVmax) between TC and AC was investigated using t test.
Results All the 16 cases were solitary and showed uniform lesion density and no necrotic cystic degeneration nor calcification. The CT value was(38±7) HU. Nine and seven cases were central and peripheral types, respectively. Out of the nine central type cases, eight showed iceberg lesions, and five presented obstructive pneumonia. However, obstructive pneumonia was absent in the seven cases of peripheral pulmonary carcinoma. In total, 1 case exhibited multiple bone metastases through PET/CT, whereas the remaining 15 cases revealed no lymph node nor distant metastasis. The tumor size and SUVmax were (2.59±1.00) cm and 4.00±1.64, respectively. No correlation was found between the SUVmax and tumor size (r=0.238, P=0.375). The SUVmax of TC and AC reached 3.32±1.17 and 5.49±1.60, respectively, with significant difference between two groups (t=−3.083, P=0.008).
Conclusions The 18F-FDG PET/CT manifestations of most lung carcinoid tumors were round soft tissue nodules or masses with mild 18F-FDG uptake. Iceberg sign was detected in most central lung carcinomas, whereas necrotic cystic degeneration and calcification were rare.