Objective  To explore the application and image characteristics analysis of enhanced CT combined with ¹⁸F-fluorodeoxyglucose (FDG) PET/CT in the diagnosis of pulmonary sequestration (PS).

Methods  The clinical data of six patients with PS treated at the Affiliated Qingdao Central Hospital of Qingdao University from October 2007 to December 2020 were retrospectively analyzed. They were composed of two males and four females, aged (49.8±17.5) years, who were surgically confirmed to be accompanied by elevated levels of tumor markers. ¹⁸F-FDG PET/CT and enhanced CT were performed in the six patients, and the location of the lesions, maximum diameter, morphology, density, CT enhancement characteristics, and ¹⁸F-FDG metabolism were observed.

Results  The lesions in the six patients were all located in the posterior basal segments of the lower lobes of the lungs. Four cases showed lesions in the right lung, and two in the left lung. The maximum diameter of the lesion was (4.3±2.0) cm, and the CT value on plain scan was (27.2±13.9) HU. Two patients had oval lesions, two patients had nearly round lesions, two patients had nearly triangular lesions, and one patient had calcified foci within the lesion; one patient had severe enhancement on the CT image, four had moderate enhancement, and one had no obvious enhancement. Six patients had abnormal arterial blood supply originating from the thoracic aorta. Two patients had cystic mass, three patients had solid mass, and one patient had cystic solid mass. Three patients had localized vascularization, coarsening, and disorganization in the lobes of the lungs. Two patients had moderately increased ¹⁸F-FDG metabolism, three patients had mildly increased metabolism, and one patient had no increased metabolism.

Conclusions  Enhanced CT images of PS show abnormal blood-supplying arteries, while ¹⁸F-FDG PET/CT images often show no metabolic increase or mild increase in ¹⁸F-FDG metabolism. Enhanced CT combined with ¹⁸F-FDG PET/CT can improve the accuracy of PS diagnosis.