Diagnostic value of 18F-FDG PET/CT in solitary pulmonary lesions and analysis on the causes of misdiagnosis

Abstract

Objective To evaluate the diagnostic value of 18F-FDG PET/CT in solitary pulmonary lesions and to analyze the causes of misdiagnosis.Methods Thirty-two patients with solitary pulmonary lesions detected by 18F-FDG PET/CT were enrolled into this study and reviewed retrospectively.All the lesions were confirmed by histopathology.The possible causes for wrong-interpretation based on 18F-FDG PET/CT findings were investigated.Statistical analysis was performed using SPSS 16.0.The correlations between the SUVmax of early phase ( SUVmax,early) or the percentage change in SUVmax between early and delayed phases( ASUVmax ) and the lesion size were tested by Pearson analysis,respectively.Results 18F-FDG PET/CT had a detection accuracy of 68.75％ (22/32) for solitary pulmonary lesions.Among 32 cases,there were 5 false negatives and 5 false positives based on 18F-FDG PET/CT.The SUVmax,early was less than 2.5 in 6 of 22 malignant pulmonary lesions.The SUVmax,early in 2 of 10 benign pulmonary lesions was ≥2.5.The △SUVmax was less than 15％ in 5 of 22 malignant pulmonary lesions.As for the 10 benign pulmonary lesions,△SUVmax was ≥15％ in 4 cases.The average size (largest dimension) of 32 pulmonary lesions was ( 1.98 ± 1.08) cm,with 26 lesions smaller than or equal to 3 cm and 6 lesions larger than 3 cm.The SUVmax was positively correlated with the lesion size ( r =0.690,P ＜ 0.01 ),but there was no correlation between △SUVmax and the lesion size (r =- 0.081,P ＞ 0.05).Conclusions 18F-FDG PET/CT plays an important role in the diagnosis of solitary pulmonary lesion.However,SUVmax alone has its limitations; it is best to combine measurements with CT and other diagnostic parameters. Key words: Lung neoplasms; Lung diseases ; Tomography,emission-computed ; Tomography,X-ray computed; Deoxyglucose