Intravenous contrast medium and renal cyst.

There are many reasons for what is apparently a benign renal cyst being hyperdense on computed tomography (CT). A previous intravascular contrast material injection (intravenous urogram or arteriogram) within one to three days is cited as one of the possible causes. This prospective study of 13 patients with renal cyst was designed to investigate such a possibility. None of the patients had a hyperdense renal cyst on delayed CT scan following contrast injection. We conclude that intravenous contrast material is not a cause of hyperdensity of a renal cyst on CT.