Subjects who have TIPS (transjugular intrahepatic porto-systemic shunts) have measurements taken to determine if someone has increased blood pressure in the portal vein of the liver (portal hypertension). Subjects who have a TIPS receive clinical ultrasounds every 3 months to determine if the TIPS is working properly.

Subjects who have a TIPS (transjugular intrahepatic portal-systemic shunt) for portal hypertension will undergo a clinical 3D ultrasound to determine if the TIPS is working properly. Additional ultrasounds will be obtained during the subject's clinically ordered ultrasound(s). These measurements will be taken by using a second ultrasound probe (plastic hand held device that is rubbed along the subject's abdomen). 15 minutes will be added to your clinically ordered exams that are completed 4 times a year.

To determine the number of volumes to achieve a specified variance in the measurement and to determine the reproducibility of the volume flow measurements taken at multiple locations within the stent (3 locations with 3 measurements each for a total of 9 acquisitions).

The physicians will measure volume flow rate three times at three different locations in the shunt (that being proximal, medial and distal) to determine the reproducibility of the flow estimate.