Scintigraphic documentation of systemic-portal shunting

Two unusual cases of iliac vein thrombosis are presented. They were studied with radionuclide venography of the left lower-extremity in which one of the collateral channels was the inferior mesenteric vein and showed the entire liver and lungs simultaneously. This vein does not appear to have been clearly identified with radioisotopic techniques previously. Using the anterior projection over the lungs and liver, ratios of liver to lungs, liver to (liver + lungs), right lung to (liver + lungs) and left lungs to (liver + lungs) were calculated. In patient 1, the shunted tracer represented 82% of the total activity and in patient 2 it was 21.5%.