Peritoneoscopy of the liver stained by intravenous injection of indocyanine green-experimental and clinical studies.

Liver surface patterns were observed by peritoneoscopy after intravenous injection of indocyanine green (ICG). The normal rat liver was diffusely stained dark greenish-brown 5 minutes after the injection of ICG 25 mg/kg body weight into the tail vein. Green spots persisted longer in the centrolobular area, clearly revealing lobular markings. This regional difference in hepatocyte staining suggested differing abilities of hepatocytes to take up or excrete ICG. This dyeing technique was applied to liver disease patients. The liver was diffusely stained light greenish-brown 5 minutes after the injection of ICG 5 mg/kg body weight. In patients, especially those with obscure lobular markings before ICG injection, lobules were clearly demarcated by reddish terminal portal veins against a green background. This simplified detection of lobular distortions. Prenodular patches (Kalk's Bunteflecke) on the liver surface were stained green more intensely than surrounding areas, which supports the hypothesis that patches are composed of active hepatocytes.