Should a computed tomography (CT) liver scan be ordered with contrast to evaluate a portal vein stent?

CT Liver with Contrast for Portal Vein Stent Evaluation

Yes, CT liver should be ordered with intravenous contrast to evaluate a portal vein stent, as contrast-enhanced portal-venous CT angiography is the method of choice for anatomical visualization of the portal-venous vascular axis and stent patency. 1

Primary Imaging Recommendation

Contrast-enhanced portal-venous CT angiography is explicitly recommended as the method of choice for anatomical visualization of portal vein stents and the portal-venous vascular axis. 1 This represents the gold standard for cross-sectional imaging evaluation of these stents according to the most recent 2025 EASL guidelines.

Rationale for Contrast Administration

• Contrast enhancement is essential for detecting stent dysfunction, including filling defects that may partially or totally occlude the vessel lumen, and for visualizing rim enhancement of the vessel wall that indicates thrombosis 2

• Portal venous phase timing is critical for optimal visualization of the portal vein and stent, as this phase provides maximal opacification of the portal venous system occurring approximately 13.9 seconds after aortic enhancement 3

• Non-contrast CT cannot adequately assess vascular patency or differentiate between patent stent lumens and thrombotic occlusion 1

Clinical Context and Surveillance Algorithm

• Doppler ultrasound should be the first-line screening modality for routine surveillance every 6 months, with sensitivity of 0.82 for stenosis and 0.96 for complete occlusion 1

• Contrast-enhanced CT is indicated when:

  • Doppler ultrasound suggests stent dysfunction 1
  • Clinical suspicion exists (recurrent ascites, variceal bleeding) 1
  • Ultrasound findings are technically limited or inconclusive 1

• Pre-procedure CT with contrast is recommended before planned TIPS placement to determine portal vein patency and detect anatomical variations 1

Important Technical Considerations

• Metal artifacts from covered stents can limit assessment on both CT and MRI, though CT angiography generally provides superior intraluminal visualization compared to MR angiography 1

• High-grade stenoses may not be reliably differentiated from complete occlusions on imaging alone, and hemodynamic assessment via invasive portography may be required in cases of diagnostic uncertainty 1

• Portal venous phase contrast-enhanced CT provides optimal timing for stent evaluation, as this phase maximizes portal vein opacification and allows assessment of both the stent lumen and surrounding vascular structures 2, 3

Common Pitfalls to Avoid

• Do not order non-contrast CT alone for portal vein stent evaluation, as it cannot adequately assess patency or detect intraluminal thrombus 1, 2

• Avoid early post-procedure Doppler ultrasound (within 7-14 days) as the acoustic barrier of covered stents makes flow measurements technically difficult during this period 1

• Do not rely solely on imaging when clinical symptoms suggest dysfunction; invasive portography with pressure measurements remains the gold standard for confirming hemodynamically significant stenosis 1