Diagnostic Ultrasound - Abdomen and Pelvis

Portal Vein Occlusion
Diagnoses: Liver
TERMINOLOGY
• Definition: Obstruction of portal vein due to thrombosis
IMAGING
• Color/spectral Doppler sonography
○ Surveillance and initial diagnosis
○ Absent blood flow within PV on color or spectral Doppler
US
○ Cavernous transformation of PV
• CECT/MR
○ Comprehensive evaluation: Extent of occlusion and
collateralization
○ Search for etiology and underlying condition
TOP DIFFERENTIAL DIAGNOSES
• Hepatic vein/IVC occlusion
• Splenic vein occlusion
• False-positive PV occlusion
• False-negative PV occlusion
KEY FACTS
• Nonocclusive thrombosis
• Dilated bile duct
PATHOLOGY
• Etiology
○ Thrombosis due to flow stasis, hypercoagulability,
intraabdominal inflammation
○ Tumor thrombus ordirect tumor invasion
• Acute thrombosis
○ Lumen filled with thrombus, diameter may be enlarged
• Chronic thrombosis
○ Lumen occlusion accompanied by cavernous
transformation
DIAGNOSTIC CHECKLIST
• False-positive/-negative diagnoses are a problem
○ Appropriate Doppler ultrasound technique essential
(Left) Grayscale ultrasound of
the liver shows mildly
echogenic thrombus ſt in the
main portal vein. (Right)
Power Doppler ultrasound in
the same patient confirms
absent flow within the
thrombosed main portal vein
ſt. Note the presence of
ascites as well as underlying
liver cirrhosis, which is a risk
factor for development of
portal vein thrombosis.
(Left) Grayscale ultrasound
shows an echogenic,
chronically thrombosed main
portal vein and adjacent
collateralized flow ſt
(cavernous transformation of
the portal vein). (Right) Color
Doppler ultrasound in the
same patient shows
collateralized flow ſt in the
porta hepatis in this patient
with chronic portal vein
thrombosis . Color Doppler
signal is heterogeneous
because portal vein collaterals
are tortuous, resulting in flow
going both towards as well as
away from the transducer.
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