Abstract
In routine oncological FDG-PET/CT studies, intravenous iodinated contrast material (CM) is not generally used, which is a major advantage of FDG-PET/CT compared to contrast-enhanced CT studies in detection of LRV variations. Unlike FDG-PET/CT, MRI is contraindicated in patients with cardiac pacemakers. Also, some unique features of FDG-PET/CT imaging are helpful in differentiation of RLRV or CLRV from other neighbouring structures. Metastatic retroperitoneal lymph nodes demonstrate increased FDG uptake which provide us to differentiate them from the major LRV variations. Additionally, FDG collected in the left renal pelvis or in the left ureter can somehow simulate the contrast effect of iodinated CM, helping us distinguish these structures from the neighbouring LRV. In my opinion, above mentioned imaging methods other than FDG-PET/CT are not necessary to exclude any RLRV or CLRV in vast majority of cases during routine oncological FDG-PET/CT practice.
In conclusion, in oncological FGD-PET/CT imaging I highly recommend to identify and report any major LRV variations on routinely obtained abdominal fused PET/CT images and abdominal plain CT images of the same patient, without performing any additional scanning in order not to give unnecessary radiation to the patient.

Key words: Abdominal FDG-PET/CT Image, Coincidental Diagnosis, Left Renal Vein Variation