Color Doppler duplex ultrasound of the portal venous system (portal vein, superior mesenteric vein, splenic vein)

Color Duplex Doppler Study of the Portal Venous System is a modern ultrasound method that simultaneously evaluates the anatomical condition of the vessels and the parameters of portal blood flow.
The method combines:

B-mode — grayscale visualization of the vessels and adjacent organs;
Spectral Doppler — quantitative assessment of the velocity, direction, and nature of blood flow;
Color Doppler (CDC) — flow mapping with the ability to identify collaterals and areas of reduced or absent patency.
This study is the European standard in the diagnosis of portal hypertension, thrombosis, and other vascular liver pathologies.

Anatomical Components

• The portal vein (v. portae hepatis) is the main venous vessel that collects blood from the digestive organs, spleen, and pancreas, and directs it to the liver.
• The splenic vein (v. splenica) drains the spleen and forms the portal vein together with the superior mesenteric vein.
• The superior mesenteric vein (v. mesenterica superior) collects blood from the small intestine, cecum, and ascending colon, contributing to the formation of the portal trunk.
• The intrahepatic branches of the portal vein distribute blood flow across liver segments for detoxification, metabolism, and filtration processes.
• These structures form the portal venous system, which plays a key role in portal hemodynamics and liver function.

Role of the Study

• Diagnosis and assessment of the degree of portal hypertension.
• Detection of thrombosis, cavernous transformation, and portocaval collaterals.
• Analysis of blood flow in the portal, splenic, and superior mesenteric veins.
• Monitoring patients with cirrhosis, fibrosis, or chronic hepatitis.
• Postoperative control after TIPS (transjugular intrahepatic portosystemic shunt) and other liver or portal system surgeries.

Indications

• Liver cirrhosis of any etiology.
• Chronic hepatitis, liver fibrosis.
• Splenomegaly, ascites.
• Suspected thrombosis of the portal or splenic vein.
• Preoperative assessment of the portal venous system.

Contraindications

Absolute: none.
Relative: pronounced flatulence, severe abdominal pain (may reduce imaging quality).

Patient Preparation

• The purpose of preparation is to reduce intestinal gas formation, which can hinder visualization of deeply located vessels.
• A fasting period of at least 6 hours (ideally 8 hours) is recommended before the examination.
• The day before the study, avoid foods that cause gas formation (cabbage, legumes, raw vegetables and fruits, dairy products, carbonated beverages, black bread, sweets).
• As prescribed by a physician, simethicone may be taken — 2 capsules × 3 times daily.
• Regular medications are taken as usual; diabetic patients require individualized adjustment of fasting regimens.
• On the day of the study, it is advisable to avoid smoking, chewing gum, and carbonated drinks, as they increase air swallowing and impair vascular visualization.
• For more accurate evaluation, previous ultrasound, CT, or MRI results should be provided.
• In emergency cases, the examination can be performed without preparation, although image quality may be reduced.

Procedure

The patient lies on their back or on the left/right side.
Ultrasound gel is applied to the anterior abdominal wall, after which the physician evaluates the vessels using a convex transducer.

Visualization is first performed in B-mode to assess the anatomy of the liver and vascular structures. Then, blood flow is analyzed using color Doppler mapping (CDC) and spectral Doppler to measure flow direction and velocity.

The examination lasts approximately 10–20 minutes. The procedure is painless, noninvasive, and completely safe.

Sources:

https://radiopaedia.org/articles/portal-vein
https://www.ncbi.nlm.nih.gov/books/NBK567725/
https://radiopaedia.org/articles/portal-hypertension
https://radiologykey.com/the-role-of-ultrasound-in-portal-hypertension/
https://pmc.ncbi.nlm.nih.gov/articles/PMC4701371/
https://pubs.rsna.org/doi/full/10.1148/rg.23005