Diagnostic Ultrasound - Abdomen and Pelvis

Portal Vein Occlusion
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Diagnoses: Liver
– Abdominal sepsis → seeding of portal vein → phlebitis
→ thrombosis (e.g., appendicitis, diverticulitis, Crohn
disease, etc.)
– Hepatic vein or IVC occlusion → secondary PV
thrombosis
– Complication of surgery/liver transplantation
○ Tumor thrombus
– Hepatocellular carcinoma (most common)
– Cholangiocarcinoma
– Metastatic disease
○ Direct neoplastic invasion
– Usually pancreatic carcinoma
– Rarely other neoplasms, usually metastatic
• Genetics
○ Inherited hypercoagulability may be causative factor in
PV thrombosis
• Associated abnormalities
○ PV occlusion may be secondary to hepatic vein or IVC
occlusion
Gross Pathologic & Surgical Features
• Acute thrombosis
○ Lumen partially filled with thrombus; flow maintained
○ Lumen entirely filled with thrombus; occlusion
○ Possible associated thrombosis of splenic vein/superior
mesenteric vein
• Subacute/chronic thrombosis
○ PV replaced by tangle of collateral veins; cavernous
transformation
– Appearance 6-20 days after occlusion
– Maturation gradual, most prominent chronically
○ 2 collateral routes
– Portoportal along usual PV course
– Portosystemic: Left gastric veins or splenogastric,
splenorenal
• Tumor thrombus
○ Tumor grows within vein lumen
○ PV wall intact
• Tumor invasion
○ Tumor directly invades through vein wall
○ PV wall destroyed
Microscopic Features
• Vein wall inflammation is essential component of
thrombosis (thrombophlebitis)
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Abdominal pain and distention
– If phlebitis/inflammation → causes pain
– Obstruction → bowel edema → pain
– Bowel edema/congestion may cause ileus
– Bowel edema possibly → ascites
○ Abnormal liver function tests
• Other signs/symptoms
○ Rare acute abdomen from venous bowel infarction
○ Asymptomatic incidental diagnosis (acute)
– Nonocclusive thrombus
– PV blood flow maintained
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– Questionable clinical relevance
– Need for anticoagulation also questionable
○ Asymptomatic incidental diagnosis (chronic)
– Cavernous transformation found on US, CT, MR
– Possibly in otherwise healthy individual
– Possibly in patient with cirrhosis
– Remote disorder → PV thrombosis → effective
collateralization
○ Gastrointestinal hemorrhage from portosystemic
collaterals
Demographics
• Age
○ Usually adult, occasionally in children
• Gender
○ No gender predilection
• Epidemiology
○ Most cases of PV occlusion are related to cirrhosis or
pancreatitis
Natural History & Prognosis
• Guarded
○ Usually related to underlying condition
○ Possible gastroesophageal varices → hemorrhage
• Good prognosis if asymptomatic or incidental
Treatment
• Anticoagulation
• Supportive
• TIPS plus PV thrombectomy/thrombolysis
DIAGNOSTIC CHECKLIST
Consider
• PV occlusion when PV is not readily seen with US
Image Interpretation Pearls
• PV readily seen; nonvisualization suggests occlusion
• False-positive/-negative diagnoses are a problem; good
Doppler technique essential
• Tangle of veins in porta hepatis & absent portal vein
suggest cavernous transformation
SELECTED REFERENCES
1. Manzano-Robleda Mdel C et al: Portal vein thrombosis: What is new? Ann
Hepatol. 14(1):20-7, 2015
2. Handa P et al: Portal Vein Thrombosis: A Clinician-Oriented and Practical
Review. Clin Appl Thromb Hemost. Epub ahead of print, 2013
3. Dănilă M et al: The value of contrast enhanced ultrasound in the evaluation
of the nature of portal vein thrombosis. Med Ultrason. 13(2):102-7, 2011
4. Parikh S et al: Portal vein thrombosis. Am J Med. 123(2):111-9, 2010
5. Piscaglia F et al: Criteria for diagnosing benign portal vein thrombosis in the
assessment of patients with cirrhosis and hepatocellular carcinoma for liver
transplantation. Liver Transpl. 16(5):658-67, 2010
6. Rossi S et al: Contrast-enhanced ultrasonography and spiral computed
tomography in the detection and characterization of portal vein thrombosis
complicating hepatocellular carcinoma. Eur Radiol. 18(8):1749-56, 2008
7. Tarantino L et al: Diagnosis of benign and malignant portal vein thrombosis
in cirrhotic patients with hepatocellular carcinoma: color Doppler US,
contrast-enhanced US, and fine-needle biopsy. Abdom Imaging. 31(5):537-
44, 2006