The Radioactive (I131) Rose Bengal Hepatoscan

Abstract

The problem of delineating the liver pictorially or roentgenographically has been approached from numerous vantage points over a period of many years. To date, one of the simplest, safest, and most successful solutions lies in the employment of a radioisotope, namely, radioiodinated (I¹³¹) rose bengal. Although the value of scintiscanning the brain and thyroid gland has been well established, application to hepatic disease has not, as yet, gained wide acceptance as a diagnostic procedure. The present report will summarize findings obtained with the radioactive rose bengal hepatoscan in more than 200 cases, by an automatic scintiscanning technic. Historical Initially, radiopaque materials were utilized in an attempt to delineate the liver, and emulsified iodinated fats were administered via the oral and intravenous routes. Most of the media had to be abandoned because of toxic reactions (1–5). As far back as 1929, Radt (6), using intravenous thorium dioxide, obtained excellent hepatic opacification. About 90 per cent of the long-lived (1.65 × 10¹⁰ years) colloidal particles, however, were permanently engulfed by the reticuloendothelial system and instances of late fibrosis and neoplasms of the liver and spleen began to appear in the literature. Later workers, circumventing selective phagocytosis, introduced contrast media into the hepatic circulation by the percutaneous transhepatic approach (7), by direct injection into the portal vein at laparotomy (8, 9), or by translumbar injection of the aorta above the celiac axis (10, 11). With the advent of radioisotopes, a completely new avenue of approach was made possible and interest was centered on rose bengal, which had been used, since its introduction by Delprat in 1923, for liver function tests (12). Taplin et al. (13) inaugurated the I¹⁸¹-tagged rose bengal liver function test in 1955 and determined uptake and excretion by means of curves obtained by directing a gamma ray counter over rabbit livers after intravenous injection of the dye. They corroborated the finding of Mendeloff (14) that intravenously injected rose bengal appears only in the hepatic polygonal cells, by administering reticuloendothelial-system-blocking agents and demonstrating continuing normal rose bengal liver uptake-excretion patterns. They showed that abnormalities of uptake and excretion in animals with hepatocellular damage could be detected as early as one hour after the administration of CC1₄. Subsequent favorable experiences with the test were reported (15–18), although some workers (19, 20) were not impressed with its ability to differentiate obstructive from hepatic jaundice. Other investigators (21–24) evaluated radioactive iodinated human serum albumin as the tracer material and elaborated on the previously used external counting technic. Instrumentation Refinements in instrumentation were meanwhile paralleling clinical interest.