Diagnosis of Portal Vein Thrombosis
Yes, portal vein thrombosis can be diagnosed using both ultrasound and CT, with Doppler ultrasound serving as the first-line investigation followed by contrast-enhanced CT for confirmation and detailed assessment. 1, 2, 3
Initial Diagnostic Approach
Begin with Doppler ultrasound as your primary screening tool. The European Association for the Study of the Liver and American Association for the Study of Liver Diseases both recommend this as the first-line investigation. 1, 2, 3
Look for these specific ultrasound findings:
- Absence of flow within the portal vein 1, 2, 3
- Hyperechoic thrombus visible in the portal lumen 1, 2, 3
- Flow reversal within the portal system (100% specific for clinically significant portal hypertension) 1, 3
Ultrasound has proven sensitivity that improves significantly when combined with Doppler capabilities, and contrast-enhanced ultrasound (CEUS) can further distinguish benign from malignant thrombus with high accuracy. 4
Confirmatory Imaging with CT
Proceed immediately to contrast-enhanced CT scan in the portal venous phase for definitive diagnosis. 1, 2 This is not optional—it provides critical information that ultrasound cannot reliably deliver.
CT scan is essential for:
- Confirming the diagnosis 1, 2, 3
- Assessing thrombus extension to mesenteric veins and arches 1, 2, 3
- Identifying local causative factors 1, 2
- Detecting bowel congestion or ischemia 1, 2
- Evaluating for life-threatening complications 1, 2
Critical CT Findings
On dynamic CT, you will see:
- Decreased density of portal vessels with peripheral arterial concentration of contrast material surrounding the intraluminal thrombus 5
- Enlarged involved vessels 5
- For acute thrombosis: spontaneous hyperdense clot in portal vein lumen on non-enhanced CT 1, 2, 3
Common Pitfalls to Avoid
Do not rely on late arterial phase images for portal vein thrombosis diagnosis—these are suboptimal and can create false positives due to delayed contrast arrival from low portal vein flow. 2 Always use portal venous phase imaging.
Watch for signs of intestinal infarction, which require immediate intervention:
- Persistent severe abdominal pain despite anticoagulation 2, 3
- Organ failure, massive ascites, or rectal bleeding 2, 3
- CT findings of distal thrombosis, bowel wall abnormalities, mesenteric stranding, pneumatosis, or portal venous gas 2
Distinguishing Acute from Chronic Thrombosis
Acute thrombosis presents with:
- Clinical presentation with abdominal pain and/or systemic inflammatory response 1, 2, 3
- Spontaneous hyperdense clot on non-enhanced CT 1, 2, 3
- Absence of portal cavernoma formation 1, 2, 3
Chronic thrombosis shows cavernous transformation on follow-up imaging. 5
Follow-Up Imaging Protocol
Perform CT scan at 6-12 months to assess recanalization of the portal venous system. 1, 2, 3
Use Doppler ultrasound early and then every 6 months for ongoing surveillance. 1, 3 This aligns with hepatocellular carcinoma screening intervals in cirrhotic patients. 6
Screen for gastroesophageal varices in patients with persistent occlusion, as portal hypertension develops in these cases and carries risk of variceal bleeding. 6, 1, 2, 3