Radioisotope Scanning of the Liver and Spleen in Dextrocardia and in Situs Inversus with

KNOWLEDGE of the position of the ab-dominal organs is important in cardiac diagnosis. Thus a mirror-image dextrocardia is usually observed in a patient with complete situs inversus; this condition more frequently occurs in an otherwise normal individual than in one with a malformed heart. By contrast, when dextrocardia occurs without situs in-versus, malformation of the heart is the rule. When the heart occupies its normal position but situs inversus of the viscera is present, the heart is almost always seriously malformed. Partial situs inversus is now known to be relatively common in patients with dextro-cardia and severe multiple intracardiac defects and is occasionally seen in patients with levo-cardia. The term "visceral heterotaxy"1 has been used to denote partial situs inversus with a midline cecum or a symmetrical liver and is common in association with asplenia.2 A-splenia, although rare, is usually associated with severe cardiac malformations. Accurate localization of the liver may be difficult, es-pecially if its lobulation is unusual or its con-tour symmetrical. Although the spleen when present uniformly lies on the same side as the stomach, the diagnosis of asplenia is uncer-tain. An ancillary method for the demonstra-tion of the position of the liver and spleen appeared desirable. Radioisotope scanning of the liver was first described by Friedell et al.3 The basic princi-ple of this method is the visualization of th