Sonographic demonstration of portal hypertension: the patent umbilical vein.

The remnant of the umbilical vein, the ligamentum teres, is seen on a high percentage of normal ultrasonograms. In patients with portal hypertension, the umbilical vein often reopens as a collateral vessel and can be visualized sonographically; the authors have recently demonstrated this finding in 30 patients. Recognition of a patent umbilical vein is important, since it currently is the only ultrasonographic finding specific for portal hypertension.