From the Guidelines
The primary purpose of an ultrasound portovenous Doppler study is to evaluate blood flow in the portal venous system, particularly to demonstrate hemodynamic alterations indicative of portal hypertension, as stated in the 2020 study by the Journal of the American College of Radiology 1. This procedure is crucial for assessing patients with suspected long-standing chronic liver disease, as it can be used in combination with conventional grayscale US for initial evaluation. The study highlights that Doppler US can demonstrate hemodynamic alterations indicative of portal hypertension, typically seen in the setting of long-standing fibrosis or cirrhosis.
Key Points of the Procedure
- The test is non-invasive and uses sound waves to detect movement of blood cells, providing information about flow direction, velocity, and any obstructions.
- It is recommended for patients with suspected portal hypertension, liver cirrhosis, portal vein thrombosis, or to assess liver transplant vasculature.
- The examination involves applying gel to the abdomen and using an ultrasound probe to visualize and measure blood flow in the portal vein, hepatic veins, splenic vein, and superior mesenteric vein.
- The test typically takes 30-45 minutes and requires fasting for 6-8 hours beforehand to reduce intestinal gas that could interfere with imaging quality.
Clinical Significance
The information obtained from the Doppler component of this ultrasound helps physicians diagnose conditions like portal hypertension, which can lead to complications such as varices and ascites, or identify thrombosis (blood clots) that may require anticoagulation therapy, as supported by the study 1. This highlights the importance of the portovenous Doppler study in the management and diagnosis of liver diseases.
From the Research
Purpose of Ultrasound Portovenous Doppler Study
The purpose of an ultrasound (US) portovenous Doppler study is to:
- Evaluate blood flow in the portal venous system 2, 3, 4, 5, 6
- Diagnose portal vein thrombosis (PVT) and distinguish between acute and chronic forms 2, 3, 5
- Detect hepatofugal flow (flow directed away from the liver) in the portal venous system 4, 6
- Assess the direction of blood flow in the portal trunk, splenic vein, and superior mesenteric vein 4
- Evaluate the patency of portosystemic shunts and determine overall prognosis in patients with cirrhosis 6
- Guide treatment decisions, such as anticoagulation therapy and thrombolytics 2, 3, 5
Key Findings
- Color Doppler ultrasound is the first-line imaging study for diagnosis of PVT 5
- Doppler sonography can detect fresh thrombus and distinguish between benign and malignant thrombus 3
- Hepatofugal flow can be demonstrated at Doppler ultrasonography, magnetic resonance imaging, and computed tomography (CT) 6
- Detection of hepatofugal flow is clinically important for diagnosis of portal hypertension and determination of portosystemic shunt patency 6