Figure 13a. Urinary excretion of FDG. (a) Axial FDG PET images (left image obtained at a higher level than right image) show the common finding of focal urinary FDG activity in the upper-pole calix of the left kidney (arrowhead). (b) Consecutive axial FDG PET images (shown from superior [top left] to inferior [bottom right]) of a patient with lung cancer show focal urinary FDG activity in the upper-pole calix of the left kidney (arrows) and a metastasis to the left adrenal gland (arrowheads). (c) CT scan of the same patient as in b clearly shows the relationship between the left adrenal mass and the left upper-pole calix. (d, e) Axial FDG PET images (shown from superior [top left] to inferior [bottom right]) (d) and a coronal FDG PET image (e) show isolated urinary FDG activity in a small extrarenal pelvis (arrows). This finding could be misinterpreted as FDG-avid paraaortic or renal hilar lymph nodes if the relationship to the kidney is not clearly demonstrated. (f) Correlative CT scan shows intrapelvic fat with a small, medially displaced ureter (arrow).