Learning objectives
To provide a comprehensive review of the role of dynamic MRI in assessment of portal vein normal anatomy, variants and acquired abnormalities in cirrhotic liver & assessing the associated hepatic parenchymal changes.
Background
The portal system represents the main abdominal digestive tract venous drainage including lower esophagus & excluding lower anal canal, conveying abdominal viscera drainage & ending at the hepatic sinusoids.
Common radiologic modalities of portal venous assessment, include: colour Doppler, CT and MRI.
Knowing portal vein abnormalities, their imaging features and interventional options helps early and accurate diagnosis & proper treatment.
Portal vein anatomy:
The portal vein results fromconfluence of superior mesenteric and splenic veins posterior to the pancreatic neck.
I-Normal anatomy:
II-Anatomical variants:
MRI technique:...
Findings and procedure details
Summary of common and uncommon acquired portal vein abnormalities in cirrhotic liver:
I- Portal hypertension & portosystemic collaterals:
Normal portal venous pressure= 5-10 mm/Hg with the normal hepatovenous pressure gradient (HVPG) (pressure gradient between PV and IVC)= 1-5 mm/Hg.
Increased portal venous pressure secondary to portal in-flow resistance occur at the level of the Portal vein, hepatic sinusoids or hepatovenous out-flow. Progressive splanchnic vasodilatation aggravates portal hypertension by augmenting portal blood flow.
Ongoing portal hypertensionleads to formation of collateral circulation directly connecting portal vessels to...
Conclusion
Dynamic MR facilitates the detection and adequate interpretation of portal vein abnormalities.
Personal information and conflict of interest
S. H. I. Desoukey; Giza/EG - nothing to disclose F. E. Balah; 6 october/EG - nothing to disclose M. H. A. Hassan Elsharkawy; Giza/EG - nothing to disclose A. H. A. Mohamed; Cairo/EG - nothing to disclose A. E. S. Hanaa; Giza/EG - nothing to disclose
References
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Madhusudhan K.S., Vyas S., et al. Portal vein abnormalities: an imaging review. Clinical Imaging. 2018; 52: 70–78.
Donato H., Franca M., et al. Liver MRI: from basic protocol to advanced techniques. European Journal of Radiology. 2017; 93: 30-39.
Hussain S., Reinhold C. & Mitchell D. Cirrhosis and Lesion characterization at MR Imaging. RadioGraphics. 2009; 29:1637–1652.
Pargewar S., Rajesh S., et al. Imaging and radiological...