How to diagnose portal vein thrombosis (PVT)?

From the Guidelines

To check for portal vein thrombus, Doppler ultrasound should be used as the first-line investigation, followed by CT scan for diagnostic confirmation and assessment of extension, as recommended by the EASL clinical practice guidelines 1. The diagnosis of portal vein thrombus (PVT) is crucial, and imaging studies play a vital role in its detection.

• Doppler ultrasound is typically the first-line diagnostic test due to its non-invasive nature, wide availability, and lack of radiation exposure, and it may detect an absence of flow within the portal vein or the presence of a hyperechoic thrombus in the portal lumen 1.
• CT scan with intravenous contrast is another excellent option, offering detailed visualization of the portal venous system and surrounding structures, and it provides additional information regarding the extent of the thrombus to the mesenteric veins and arches, the presence of a local factor, or of congestion and ischemia of the bowel 1.
• MRI with contrast can provide even more detailed images and is particularly useful for evaluating the extent of thrombus.
• Laboratory tests including liver function tests, complete blood count, and coagulation studies should accompany imaging to assess liver function and identify underlying hypercoagulable states. When portal vein thrombus is suspected, prompt diagnosis is crucial as early intervention with anticoagulation therapy can prevent extension of the clot and development of portal hypertension, and patients with risk factors such as cirrhosis, malignancy, recent abdominal surgery, or hypercoagulable disorders should be monitored closely 1.
• The EASL clinical practice guidelines recommend considering the diagnosis of acute portal vein obstruction in any patient with abdominal pain, and using Doppler ultrasound as the first line investigation for acute PVT, and CT for diagnostic confirmation and the assessment of extension 1.
• It is also recommended to establish or rule out underlying cirrhosis or obliterative portal venopathy, and to consider intestinal infarction in patients with persisting severe abdominal pain, rectal bleeding, moderate or massive ascites, or multiorgan dysfunction 1.
• Anticoagulation therapy should be given for at least 6 months, and a CT scan should be performed to assess recanalisation of the portal venous system at 6-12 months follow-up 1.
• Screening for gastroesophageal varices in unrecanalised patients is also recommended, as well as performing MR imaging cholangiography in patients with persisting cholestasis or biliary tract abnormalities suggestive of portal biliopathy 1.

From the Research

Diagnosis of Portal Vein Thrombus

To check for portal vein thrombus, the following imaging methods can be used:

• Ultrasound: as a initial screening method to diagnose portal vein thrombosis 2, 3, 4
• Doppler ultrasound: to distinguish between a benign and malignant thrombus 2
• Magnetic resonance angiography: if further information is required 2
• Contrast-enhanced computed tomography: if further information is required 2
• Digital subtraction angiography: if other tests are unsatisfactory 2

Imaging Modalities

The imaging modality of choice in diagnosing portal vein thrombosis is:

• Abdominal ultrasound color Doppler imaging, which has a 98% negative predictive value 3
• Color Doppler imaging has a sensitivity of 89% and specificity of 92% for detection of portal vein thrombosis 4

Role of Imaging

Imaging plays a central role in:

• Diagnosing portal vein thrombosis 5
• Clarifying its etiology 5
• Choosing the best therapeutic approach 5
• Screening possible complications 5
• Differentiating portal vein thrombosis from neoplastic invasion of the portal vein 5