Functional measurement of nonfibrotic hepatic mass in cirrhotic patients

We have postulated that the perfused hepatic mass (PHM) can be estimated by quantitative (volumetric) liver spleen scan (QLSS) using single photon emission computed tomography assessment of sulfur colloid distribution between liver, spleen, and bone marrow. Thus, this parameter should correlate with the amount of functioning tissue in the liver. As a "gold standard" estimate of the nonfibrotic functioning hepatic mass, the weight of the liver at autopsy or transplant was corrected for the amount of scar tissue present. QLSS parameters were correlated with functional hepatic mass in 13 patients with advanced liver disease with liver available at transplant (8 patients) or autopsy (5 patients) who had prior QLSS.

Greater than 1000 mm2 of a liver tissue was assessed histologically in all patients and from more than 2 regions of the liver in 9 of 13 patients. The total fibrosis score (TFS) (range, 0-17.5) was calculated as a semiquantitative estimate of hepatic fibrosis. The ratio of functioning tissue was calculated as (1 - TFS/20) and the amount of functioning tissue as the nonfibrotic weight (NFW): NFW = liver weight x (1--TFS/20). QLSS parameters were measured postprandially and 30 min after injection of 5 mCi of technetium Tc 99m sulfur colloid. Pixel and total counts from the liver, spleen, and bone marrow as well as organ length were measured. Liver/bone marrow index and liver/spleen index were calculated. The perfused hepatic mass (PHM) was defined as the mean of the liver/bone marrow index and liver/spleen index.

All patients had cirrhosis: alcoholic (1 patient), alcoholic with alcoholic hepatitis (1 patient), hepatitis B (3 patients), hepatitis C (6 patients), hepatitis C with hepatocellular carcinoma (1 patient), and primary sclerosing cholangitis (n = 1). The ratio of functioning tissue was 0.54 +/- 0.07; liver weight 1215 +/- 317 g; and NFW = 658 +/- 193 g. The PHM = 55 +/- 14. The PHM calculated from the QLSS correlated strongly with the NFW (functioning tissue) at autopsy/transplant: NFW = 13 PHM - 55; r = 0.9505; p < 0.0001).

In cirrhotic patients (a) we have confirmed that the sulfur colloid distribution by QLSS is determined by the perfused hepatic mass, and (b) the amount of functioning tissue can be precisely estimated by QLSS parameters.