Febrile syndrome of unknown origin: Indications for 18F-FDG PET/CT in inflammatory and infectious processes

The Association Between Lung Fluorodeoxyglucose Metabolism and Smoking History in 347 Healthy Adults

Objective

This study aimed to evaluate the relationship between fluorodeoxyglucose metabolism and smoking history in healthy adults by analyzing lung standardized uptake value (SUV).

Methods

The ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) studies of 347 patients who did not show signs of having malignant diseases or lung inflammation were retrospectively evaluated. Four circular regions of interest (ROI) were manually drawn on the upper and lower lung regions. The averages of maximum SUV (SUVmax-avr) and mean SUV (SUVmean-avr) were calculated, and the mean values of each parameter for non-smokers, ex-smokers, and current smokers were compared. The correlation between SUVmax-avr and smoking history (tobacco burden and the duration of smoking cessation) was assessed based on present smoking status. The ex-smokers and current smokers were divided into three groups according to their tobacco burden, and the SUVmax-avrs of the two groups were compared.

Results

Both the mean values of SUVmax-avr and SUVmean-avr increased based on smoking history, with non-smokers having the lowest values and current smokers the highest. Tobacco burden had a positive correlation with SUVmax-avr in current smokers (r = 0.474, P< 0.001). However, neither tobacco burden (r = 0171, P = 0.162) nor duration of smoking cessation (r = 0.212, P = 0.082) had a significant correlation with SUVmax-avr in ex-smokers. The mean SUVmax-avr of current smokers was significantly higher than that of ex-smokers in patients with a medium or large tobacco burden (P = 0.012, P< 0.001, respectively). Although there was no significant difference between the mean SUVmax-avrs of ex-smokers and current smokers in patients with a small tobacco burden (P = 0.888), the mean SUVmax-avrs of both ex-smokers and current smokers with a small tobacco burden were significantly higher than that of non-smokers (P< 0. 001, P< 0.001, respectively).

Conclusion

The findings indicate that lung SUV increases in current heavy smokers and partially decreases after the cessation of smoking, which is in line with previous reports studied by analyzingfluorodeoxyglucose (FDG) metabolism of lung specimens.

A bump: what to do next? Ultrasound imaging of superficial soft-tissue palpable lesions

Soft-tissue palpable lesions are common in clinical practice, and ultrasound (US) represents the first imaging option in the evaluation of a patient with a soft-tissue swelling. A full and systematic US assessment is necessary, however. This includes grayscale, color- and power-Doppler, spectral-Doppler, and possibly elastography facilities, as well as a trained operator. Several lesions showing characteristic US features can be diagnosed confidently, without any further work-up, and the high spatial resolution of ultrasound in the superficial layers can be a powerful tool to discriminate their etiologies. Second-level options, to be reserved for indeterminate cases or those suspected malignant at initial ultrasound, include magnetic resonance imaging, percutaneous fine-needle aspiration or biopsy, and surgical-excision biopsy. In this article, we discuss the proper US approach for addressing superficial soft-tissue lesions.