Dual-time point positron emission tomography findings of benign mediastinal lymph nodes in a tuberculosis-endemic region.

PURPOSE: We performed dual-time-point positron emission tomography imaging (DTPI) in patients without evidence of mediastinal lymph node metastasis to investigate the characteristics of fluorodeoxyglucose (FDG) uptake in benign mediastinal lymph nodes.

MATERIALS AND

METHODS

A total of 118 mediastinal lesions in 24 patients were included in the study. The size, attenuation, maximum standardized uptake value (SUV), and retention indices (RI) were recorded on early and delayed positron emission tomography images for lymph node characterization.

RESULTS

The mean SUVs on the early and delayed scans of 118 lymph nodes were 3.3 ± 1.2 and 4.2 ± 1.7, respectively. The mean RI was 26.4% ± 24.5%. Higher FDG uptake was observed in patients with calcified nodules and bilateral FDG uptake and in lymph nodes with calcification or a short-axis diameter >10 mm.

CONCLUSION

In a tuberculosis-endemic area, increments of SUV or RI were frequently observed in benign mediastinal lymph nodes. Therefore, these values, based on mediastinal FDG uptake, might not be accurate indicators of malignant disease.