Paraumbilical collateral veins on MRI as possible protection against portal venous thrombosis in candidates for liver transplantation

BACKGROUND: We retrospectively evaluate the potential protective influence of patent paraumblical vein (PUV) collaterals against portal vein (PV) thrombosis and reduced PV diameter in candidates for orthotopic liver transplant (OLT) METHODS: Dynamic 3D contrast-enhanced MRI at 1.5T was obtained in 309 patients with cirrhosis without evidence of malignancy. All MR studies were reviewed by one reader for PUV collaterals, PV thrombosis and PV diameter. Statistical analysis was performed by Fisher exact tests; 50 selected studies were reviewed independently by two additional readers to determine interobserver agreement via intraclass correlation coefficient (ICC). RESULTS: Patent PUV was noted in 119 of 309 patients (38.5%). Mean PV diameter was 13.4 +/- 3.0 mm in patients with PUV compared with 11.3 +/- 3.6 mm without PUV (P < 0.01). Main PV thrombosis was present in 13 of 309 patients (4.2%) and significantly more frequent in those without PUV than with PUV (6.3% vs. 0.8%, P < 0.05). ICC indicated almost perfect agreement among three readers for presence of PUV collaterals (ICC = 0.91) and PV thrombosis (ICC = 0.96). CONCLUSION: Our results suggest that patients with patent PUV appear less likely to develop main PV thrombosis or small PV diameter, suggesting a protective effect of PUV on PV patency.