Figure 4.

Axial ultrasonography with color Doppler of the left renal vein (LRV). (A) Greyscale ultrasound demonstrating significant decrease in caliber of the LRV as it crosses between the aorta (Ao) and superior mesenteric artery (SMA) towards the inferior vena cava (IVC). Liver, portal vein (PV) and vertebra are notated for anatomic reference; (B) color Doppler of the same anatomic region shows normal antegrade flow proximal to the aortomesenteric region shows significant turbulence (*) and elevated peak velocity.