Radionuclide angiography of the liver and spleen: Noninvasive method for assessing the ratio of portal venous to total hepatic blood flow and portasystemic shunt patency

Radioactivity versus time curves were generated for the first pass of technetium-99m pertechnetate through the left ventricle, kidneys, spleen and liver, after a 20 mCi peripheral intravenous bolus injection. The rate of change of radioactivity in these organs before recirculation is proportional to blood flow through the organ. The hepatic perfusion index, defined as the ratio of portal flow to total hepatic blood flow, was correlated with the angiographic grade of portal perfusion. The hepatic perfusion index in seven normal subjects was 66.0 ± 3.4 percent (mean ± standard error of the mean), and in 22 cirrhotic patients with decreasing angiographic perfusion of grades 1 to 4 the index was 54 ± 4.6, 37 ± 2.6, 17 ± 4.7 and 3 ± 1.1 percent, respectively. The correlation between the calculated perfusion index and the angiographic grade of portal flow was highly significant (p < 0.001). The passage of radionuclide through the spleen differed before and after shunt surgery in patients with portal hypertension. The slope to height ratio, based on the downslope of the splenic curve, was significantly greater (p < 0.01) in the shunted patients and provided a simple index for assessing shunt patency.