FIGURE 9. (B) PET image showed 2 foci of increased tracer uptake. In general, paired ¹⁸F-FDG-containing structures in retroperitoneum are ureters. However, examinations of CT (B) and in particular fused PET/CT (C) images showed lesion on left to clearly medial to left ureter and corresponded to <1-cm lymph node (normal size). Right focus was ureter. Left focus was in metastatic lymph node from colorectal cancer, and only PET/CT resolved this finding. (Courtesy of C. Cohade, MD)