Pathology of the Abdominal Portal Venous System

Question 1

Vena Caval Obstruction

Answer 1

S & S
-	Abdo pain, ascites, or tender hepatomegaly. 
Sono Appearance 
-	Distal IVC dilation 
-	Solid, complex or echo poor tumors. 
Causes 
-	IVC thrombosis, IVC tumors 
-	Compression from external masses 
-	Right sided heart failure

Question 2

Venous Thrombosis

Answer 2

Caused by:

• Venous Stasis
• Hypercoagulable state
• Endothelial Damage

Question 3

Tumors of the IVC

Answer 3

S & S

• Symptoms unremarkable
• Large tumors cause leg edema, ascites & Abdo pain.

Sono Appearance

• Echogenic
• Heterogenous, with areas of necrosis

Causes
- Unknown, occur spontaneously.

Question 4

Venous Enlargement

Answer 4

Localized dilation of the IVC

Question 5

Portal Vein Thrombosis

Answer 5

S & S
-	Abdo pain, hypovolemia 
-	Low grade fever & leukocytosis 
Sono Appearance 
-	echogenic thrombus 
Causes 
-	Venous stasis 
-	Hypercoagulable State 
-	Endothelial damage (Intimal Injury)

Question 6

Venous Incompetence

Answer 6

• Venous valves can become damaged
• Blood flow is no longer contained in the venous sinus but can flow back through the incompetent valve
• With increased abdominal pressure, IVC blood flow can flow backwards if incompetent veins are present in the leg veins

Question 7

Hepatic Venous Abnormalities

Answer 7

• Very rare (one in a million)
• Caused by occlusion to hepatic veins (thromboses)
• Blockage can be anywhere from small and large veins of the liver to the IVC
• Important for sonographers to recognise as this restricts the blood flow leaving the liver causing it to enlarge

S&S (Signs and symptoms):
abdominal pain, ascites, liver enlargement

Sono Appearance
- Absent, reversed, or sluggish flow in the IVC

Question 8

Portal Vein Thrombosis

Answer 8

PV thrombosis caused by the following secondary causes:

• Cirrhosis and portal hypertension (5%)
• Malignancy
• Trauma
• Hypercoagulable state
• Intraperitoneal inflammatory process (PV phlebitis)
• Budd-Chiari syndrome
• Liver transplant

Question 9

Portal Venous Hypertension

Answer 9

The main types of causes of portal hypertension

• Pre-hepatic: congenital portal atresia, PV thrombosis, phlebitis of the PV, trauma of thrombosed portocaval shunt
• Hepatic: cirrhosis (alcoholic most frequent), chronic active hepatitis, parasitic diseases (schistosomiasis)
• Post-hepatic: Budd-Chiari syndrome, constrictive pericarditis, tricuspid valve incompetence

Ultrasound Presentation:

• Dilated portal, splenic, and superior mesenteric veins
• Patent paraumbilical vein
• Varices
• Splenomegaly with dilated splenic radicles
• Diminished response to respiration in portal system
• Dilated hepatic and splenic arteries
• Ascites
• Small liver with irregular surface or large liver with abnormal texture

Question 10

Cavernous Transformation of the Portal vein

Answer 10

• Cavernous transformation of the portal vein is a consequence of portal vein thrombosis, when the multiple tortuous venous channels develop in the porta hepatis to bypass the thrombosis
• Demonstrates periportal collateral channels in patients with chronic portal vein obstruction.
• Doppler analysis of the tubular structures is characteristic of portal venous flow hepatopetal (toward the liver) with continuous low-velocity flow.

Sonographic Appearance:

• Extrahepatic portal vein is not visualised
• High-level echoes produced by fibrosis are present in the porta hepatis
• Multiple tubular structures are present in the porta hepatis, representing periportal collaterals