Vasovagal-related stress immediately before FDG injection may increase bilateral adrenal FDG uptake.

Abstract

To evaluate the relationship between vasovagal-related stress on positron emission tomography (PET)/CT and adrenal fludeoxyglucose (FDG) uptake. We reviewed the medical records of 1358 consecutive patients who underwent FDG PET/CT examinations and selected those who presented with vasovagal-related symptoms and acute hypotension immediately before FDG injection (vasovagal reflex group). Patients who underwent FDG PET/CT examinations on the same days as the vasovagal reflex group without new complaints or any adrenal lesion were used as controls. We evaluated adrenal FDG uptake visually and by means of adrenal maximum standardized uptake value (SUV(max)) and adrenal/liver (A/L) SUV(max) ratio. Next, we reviewed the FDG PET/CT images of the same 1358 patients and selected the cases presenting with bilateral avid FDG uptake. 4 patients were included in the vasovagal reflex group, and all of them showed bilateral avid adrenal FDG uptake visually, while 19 patients in the control group did not. The mean adrenal SUV(max) and the mean A/L SUV(max) ratio were significantly higher in the vasovagal reflex group than in the control group (p < 0.001). 10 (0.74%) patients, including 4 patients from the vasovagal reflex group, showed bilateral avid FDG uptake with normal adrenal configuration on CT. Vasovagal-related stress immediately before FDG injection may increase bilateral adrenal FDG uptake. Vasovagal-related stress may be included in the differential diagnosis of the cause of bilateral avid adrenal FDG uptake.