Scintiscanning in diagnostics of hepatopulmonary syndrome in children

Arterial blood oxygenation disturbances accompanying liver cirrhosis are referred to as hepatopulmonary syndrome (HPS). HPS develops due to the formation of intrapulmonary arteriovenous shunts and dilatation of the vascular bed. The aim of the study was to assess the incidence of arteriovenous shunts in children with hepatic cirrhosis and HPS suspected on the basis of clinical signs, qualified for liver transplantation.

The study was carried out in a group of 21 children aged from 1.2 to 17.7 years (mean age 8.4); 8 girls and 13 boys. The patients were diagnosed as follows: biliary cirrhosis due to extrahepatic bile duct impatency--12, post-inflammatory liver cirrhosis due to infection with HVB--2, autoimmune hepatitis--2, fibrosis of the liver--2, alpha 1-antitrypsin deficiency--1, progressive familial intrahepatic cholestasis--1, cystic fibrosis--1. The presence of arteriovenous anastomoses in the lungs was detected by scintiscanning utilizing microspheres (albumin macroaggregates). Under physiologic conditions, technetium-labeled microspheres injected i.v. are accumulated in pulmonary capillaries. Radioactivity detected in other organs (kidneys, brain) indicates the presence of pathologic shunts omitting the alveoli. A percentage ratio of radioactivity detected in the brain to that present in the lungs serves as the index of blood flow through the anastomosis (SI--shunt index). According to Grimon, the mean SI value for healthy children amounts to 0.43%, the values ranging from 1% to 2% are regarded as borderline ones, and those above 2% allow unequivocal diagnosis of HPS.

The SI values obtained in the study ranged from 0.06 to 51%. In 7 patients SI exceeded 1%, reaching 1.23% in one, and over 3% in the remaining 6 patients. No correlations were found either between SI value and the etiology of cirrhosis, or between the index and clinical condition of the patient assessed according to Child-Pugh scale.

1. Scintiscanning revealed the presence of arteriovenous shunts in the lungs of 6/21 (28.6%) investigated patients. 2. No correlation was found between the severity of HPS and the etiology and stage of the underlying disease.