Hepatobiliary imaging: a comparison of 99Tcm-dihydrothioctic acid and 99Tcm-pyridoxylidene glutamate in the non-jaundiced patient.

A comparison of two hepatobiliary imaging agents, 99Tcm-dihydrothioctic acid (99Tcm-DHT) and (99Tcm-pyridoxylidene glutamate (99Tcm-PG) has been carried out in 44 non-jaundiced patients. Thirty-one patients were admitted for investigation of upper abdominal pain and 13 patients were volunteers who were undergoing treatment for unrelated conditions. Satisfactory liver images were obtained with both agents in patients without liver disease, but they were inferior to those seen after 99Tcm-sulphur colloid. 99Tcm-PG produced clearer images of the gall-bladder and bile ducts than 99Tcm-DHT. Non-visualization of the gall-bladder was interpreted as gall-bladder disease; in patients with inflammatory gall-bladder disease no gall-bladder image was seen (nine 99Tcm-DHT, nine 99Tcm-PG). The gall-bladder was also not demonstrated in two of the volunteers' group (one 99Tcm-DHT, one 99Tcm-PG), nor was a gall-bladder seen in five patients whose abdominal pain was not due to acute cholecystitis. Despite this, there was agreement between the results of imaging and oral cholecystography in 21 out of 22 subjects. 99Tcm-PG is non-toxic, cheap and rapidly excreted by the liver into the bile. A 99Tcm-PG scan would be useful when rapid diagnosis is required in suspected acute cholecystitis when conventional contrast radiology is unlikely to be of value.