[99mTc-BIDA: functional parameters in the differential diagnosis of obstructive and parenchymatous jaundice (author's...

75 Patients were examined with 99mTc-BIDA in order to find a reliable method of differentiating between obstructive and parenchymatous jaundice. Serial scans, repeated recordings of plasma radioactivity and external measurements over a temporal and a thigh region were taken between 1 and 30 min after injection. Serum half life of radioactivity, extraction coefficient and clearance rate, calculated from the first exponential slope over the temporal region curve, differed significantly in obstructive as compared to parenchymatous diseases and normals. In patients with extrahepatic obstruction the curves over the temporal and the thigh region differed; within the first 30 min the thigh values tend to increase. Clearance and extraction coefficients calculated from the third exponential slope of the plasma curve were significantly lower in obstructive jaundice than in other groups, although the great variation in these values did not allow a reliable differentiation in every patient. However, reliable results were obtained when these parameters were considered together with serial hepatic images.