Type:
Educational Exhibit
Keywords:
Veins / Vena cava, Anatomy, Abdomen, CT-Angiography, MR, Ultrasound-Colour Doppler, Contrast agent-intravenous, Embolisation, Shunts, Varices
Authors:
A. Dev1, A. Arora1, Y. Patidar2, A. Mukund1, S. T. Laroia1, S. K. Sarin1; 1New Delhi/IN, 2Madhya Pradesh/IN
DOI:
10.1594/ecr2013/C-2547
Conclusion
The portal vein is encountered in all cross sectional imaging studies of the abdomen.
Abnormalities may be specifically sought for or detected incidentally.
Knowledge of the various congenital and acquired abnormalities of the portal vein can facilitate a definitive diagnosis and is indispensible in planning for hepatic surgery and interventional radiologic procedures.
- Variant portal vein anatomy is seen in upto 35% of the population
- Variant anatomy may render a potential liver donor unsuitable for organ donation in cases with portal venous trifurcation,
quadrification,
absent bifurcation and when segmental branches cross the interlobar boundary.
- Unrecognised type 3,
4 or 5 portal vein may cause bleeding in the donor and segmental devascularisation in recipients.
- Congenital anomalies of the portal vein,
include the portocaval shunt which are associated with liver failure and hepatic tumours.
- Portal hypertension has a varied aetiology and is characterised by altered portal vein calibre,
porto-systemic collaterals,
splenomegaly and ascites.
- Minute arterioportal shunts commonly produce perfusion anomalies in cirrhosis.
Repeat imaging in 6 months is helpful in equivocal cases.
- The outcome of portal vein thrombosis (PVT) in general is good. Portal vein thrombosis.
Pulsatile color signals within the thrombus on Doppler ultrasound and the “thread and streak sign” on CT are indicative of malignant thrombus.
- Cavernous transformation may develop as early as 6 to 20 days following acute thrombosis.
Patients present with variceal bleeding,
symptomatic portal biliopathy and hypersplenism.
- Portal biliopathy refers to biliary obstruction associated in the setting of cavernous transformation of the portal vein.
Venous engorgement of the paracholedochal and epicholedochal veins results in compression and narrowing of the bile duct lumen.
- Obliterative portal venopathy (OPV) is characterised by intimal fibroelastosis of the medium-sized portal veins,
typically diagnosed on histopathologic findings. OPV is a major cause of noncirrhotic portal hypertension.
- A liver allograft which is significantly below the standard liver weight for a reciepient,
suffers from excessive portal venous inflow with resultant early portal hypertension and increased morbidity and mortality.
- Transcatheter thrombolytic therapy is generally reserved for patients with severe complications such as bowel ischaemia.
- Portal vein embolization (PVE) is performed prior to major hepatic resection to induce selective hypertrophy of the nondiseased portion of the liver with small estimated future liver remnants.
- Transjugular intrahepatic portosystemic shunt (TIPS) is an established procedure for troublesome variceal bleeding and ascites in portal hypertension.
TIPS endografts are reported to have 1-year primary and secondary patency rates of 80% and 100%