Figure 5

¹⁸F-FDG PET/CT and contrast-enhanced MRI (CEMRI) scans of a 62-year-old man with clear cell carcinoma of the left kidney associated with a level IV venous tumour thrombus (VTT). The VTT did not invade the venous wall and was graded as level II by PET/CT and level IV by CEMRI. The site of diffusely increased FDG uptake (SUVmax 6.3) on a PET maximum intensity projection image is the primary tumour (blue arrow) (a). The VTT showed pathologically increased FDG uptake (SUVmax 3.4) from the left renal vein to the inferior vena cava below the hepatic vein (red arrow) (a). However, there was no increased FDG uptake (SUVmax 2.0) from the hepatic vein to the inferior vena cava above the diaphragm (black arrow) (a). Coronal CEMRI showed that the VTT had an irregular shape, was heterogeneously enhanced, and partially occluded the vein lumen (red arrow) (b). The primary tumour also showed heterogeneous enhancement (blue arrow) (a).