Hepatolienography: Past, Present, and Future

The liver and spleen are among the few structures in the body for which safe and reliable primary contrast roentgen diagnostic procedures have not been established. Hepatolienography with colloidal thorium dioxide2 has been widely performed for many years (65), but this material has fallen into disfavor with many workers, though not all, as a result of a number of cases in which injurious effects presumably related to its use have been reported. Since thorotrast has been in clinical use for over twenty years, there is available a rather large body of pathological and clinical material in which its long-term effects may be studied. It has seemed desirable to attempt an evaluation of these effects, to formulate criteria for an ideal medium for opacification of the liver and spleen, and to report preliminary studies with other media. I. Evaluation of the Effects of Thorotrast Thorotrast is a 25 per cent suspension of thorium dioxide (15 to 20 per cent by weight) with an average particle size of 3 to 10 millimicrons by electron microscope measurements (38). In colloidal suspension thorium dioxide is highly radiopaque, and satisfactory opacification of the liver and spleen is obtained with concentrations of less than 1 gm. of thorium dioxide per 100 gm. of wet tissue. The particulate matter is taken up by the reticulo-endothelial cells of the body and accumulates in the liver and spleen and to a lesser degree in the reticulo-endothelial system throughout the lymphatic, respiratory, and hemopoietic system. Immediate Side Effects Reactions during injection of thorotrast have been reported, although they are rather infrequent. These include mild fever lasting up to twenty-four hours, vomiting, anaphylactoid phenomena, exacerbation of asthma, transient anemia, leukopenia and relative lymphocytosis (65). Hematemesis has been reported in three patients with cirrhosis of the liver (89). In a patient observed by one of us (S. F. T.) generalized petechiae appeared following the injection of thorium dioxide (possibly due to the use of outdated thorotrast). Late Effects The late effects may be classified under two general headings: (A) possible induction of neoplasms and (B) local fibrosis at the site of injection or deposition. Thorium is radioactive, yielding alpha and gamma rays predominantly (77–79). The diagnostic dose of 75 c.c. of thorotrast is roughly equivalent to 3 micrograms of radium salt (18). Bone atrophy and necrosis and other late sequelae (anemia, etc.) have been reported with as little as 1 microgram of radium deposited in the body (51, 52). Ionizing radiation in suitable doses is known to be capable of producing a number of late injurious effects. These include local necrosis (58) and fibrosis (1), the induction of malignant neoplasms in a variety of tissues (3, 8, 15, 16, 57, 67, 73, 83), and hemopoietic derangements (12, 34, 45, 46, 50, 69, 83, 84).