In portal hypertension, hepatopetal flow is rerouted away from the liver through collateral pathways to low pressure systemic vessels. Information about collateral pathways is relevant, especially when interventional procedure or surgery is contemplated, because inadvertent disruption of these veins can cause significant bleeding. Dynamic CT and spiral CT with a bolus injection of contrast material have to a significant extent recently replaced angiography. The porto-systemic collateral pathways have, however, been classified and described according to location or frequency in a majority of previous reports. This essay illustrates variable porto-systemic collateral blood flow pathways, with CT and angiography correlation.