Before performing PET/CT, patients were required to fast for 4–6 h. Blood glucose levels were checked to ensure a glycemic range below 150 mg/dL. Then patients received an intravenous injection of 18F-FDG at 370 MBq. After 60 min of 18F-FDG administration, an FDG-PET scan from skull base to mid-thigh was performed using the Gemini GXL 16 PET/CT system, Philips Healthcare. A non-contrast, low-dose CT scan from the skull vertex to mid-thigh was conducted for attenuation correction and anatomical localization. The images were reviewed by an experienced nuclear medicine specialist (M. C. C.) with 12 years of experience in FDG-PET/CT.
The diagnosis of axillary lymph node metastases was considered positive if areas in the axillary region accumulated greater FDG than the surrounding background tissue. The number, region, clinical node staging category, and FDG avidity (SUVmax, defined as the peak standardized uptake value (SUV) in the pixel with the highest count within the region of interest) of suspicious axillary lymph nodes were recorded. The lymph nodes’ morphological size was not used in the final PET/CT criteria.
The diagnosis of axillary lymph node metastases was considered positive if areas in the axillary region accumulated greater FDG than the surrounding background tissue. The number, region, clinical node staging category, and FDG avidity (SUVmax, defined as the peak standardized uptake value (SUV) in the pixel with the highest count within the region of interest) of suspicious axillary lymph nodes were recorded. The lymph nodes’ morphological size was not used in the final PET/CT criteria.