Abnormal abdominal computerized tomography with amiodarone therapy and clinical significance

Although the antiarrhythmic agent, amiodarone, is known to cause elevation of liver function tests, the effect of this drug on abdominal computerized tomography (CT) scans in patients on amiodarone therapy is unknown. Since iodine is in its molecular structure, the presence of amiodarone or its metabolites might be expected to produce higher CT numbers similar to the effect of contrast agents. To test this hypothesis, CT scans were performed in a series of 25 patients receiving amiodarone, 14 receiving short-term (mean 2.5 +/- 1.3 days) and 19 receiving long-term therapy (mean 130 +/- 75 days), as well as in a control group not receiving amiodarone. Gastrointestinal symptoms (if any) and liver function tests (LFT) prior to instituting amiodarone therapy and at the time of CT scan were also documented. CT scans showed a modestly increased density in multiple organs in the short-term group, but a markedly increased hepatic density in all but one patient in the long-term group. Presence of gastrointestinal symptoms or abnormal LFT did not appear to correlate with the CT number. Such findings would suggest that increased hepatic density on CT scan is to be expected in patients receiving long-term amiodarone therapy, and although the exact biologic pathways of amiodarone metabolism are uncertain, the liver appears to be a major site of drug storage and/or metabolism.