Simple computer quantitation of spleen-to-liver ratios in the diagnosis of hepatocellular disease.

Increased splenic uptake of radiocolloids is a helpful sign in the scintigraphic diagnosis of various hepatocellular diseases, but little attempt has been made to quantify this physiologic phenomenon. We have devised a simple computer method that compares average splenic activity to average right-lobe liver activity. The method is reproducible (r = 0.97) and exhibits little interobserver variation (r = 0.99). One hundred clinically normal subjects were found to have a nearly symmetrical distribution of S/L ratios around a mean of 0.77, with a s.d. of 0.20. Fifteen subjects normal by biopsy were found to have a similar mean spleen-to-liver (S/L) ratio of 0.74. Based upon a normal range of 0.37 to 1.17 (0.77 +/- 2 s.d.), elevated S/L ratios were found in fatty metamorphosis (85%), cirrhosis (67%), and chronic hepatitis (43%). Abnormal S/L ratios in the range from 1.17 to approximately 1.4 were not visually obvious. Overall sensitivity of the S/L ratio in these three diseases is 69%. When combined with the other scintigraphic indications of hepatocellular disease (nonhomogenous colloid uptake, hepatomegaly, splenomegaly, and bone-marrow colloidal uptake), the liver scan was found to have a sensitivity of 93%.