title: Transjugular intrahepatic portosystemic shunt: US assessment with maximum flow velocity.
abstract: OBJECTIVE
  To evaluate the ability of Doppler ultrasonography (US) to depict the patency of a transjugular intrahepatic portosystemic shunt (TIPS).
  
  
  METHODS
  Twenty-eight patients were followed up after creation of TIPS with US, angiography, and endoscopy performed at regular intervals. Magnetic resonance (MR) angiography was performed in four patients. US was performed first, and the results were correlated with those at angiography. Measurements of maximum flow velocity (Vmax) were taken from the proximal part of the shunt.
  
  
  RESULTS
  In normal shunts, mean Vmax was 95 cm/sec. Shunt obstruction was seen in 12 cases: occlusion in four and stenosis in eight. All cases of occlusion were detected with US and appeared as absent flow within the shunt. There was one false-positive diagnosis of occlusion. All cases of stenosis resulted in reduced Vmax (mean, 32 cm/sec; P < .001). After successful revision in seven patients, Vmax rose to a mean of 122 cm/sec. Artifact from the metal stent prevented flow assessment with MR imaging.
  
  
  CONCLUSIONS
  US can be performed to evaluate shunt status, and Vmax is an accurate noninvasive parameter for assessing shunt patency.
authors.affiliation: Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN 37232-2675.
authors.forename: W K
authors.initials: WK
authors.lastname: Chong
authors.forename: T A
authors.initials: TA
authors.lastname: Malisch
authors.forename: M J
authors.initials: MJ
authors.lastname: Mazer
authors.forename: C D
authors.initials: CD
authors.lastname: Lind
authors.forename: J A
authors.initials: JA
authors.lastname: Worrell
authors.forename: W O
authors.initials: WO
authors.lastname: Richards
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology; D005500:Follow-Up Studies; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging* / Q000453:epidemiology; D006801:Humans; D006975:Hypertension, Portal / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000601:surgery*; D011168:Portal System / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011170:Portasystemic Shunt, Surgical / Q000379:methods*; D013997:Time Factors; D014465:Ultrasonics; D014463:Ultrasonography; D014654:Vascular Patency / Q000502:physiology