Valueof BowelPreparationin AdrenocorticalScintigraphywith NP-59

The use of radiolabeled cholesterol derivatives for functional imaging of the adrenal cortex may be rendered inaccurate or impossible because of the excretion of activity by the liver and its subsequent appearance in the colon. A simple bowel preparation (bisacodyl 5 or 10 mg nightly) significantly reduced bowel background activity during 6 beta-[I-131]iodomethyl-19-norcholesterol (NP-59) adrenal cortical scintigraphy. Activity interfering with image interpretability was present less frequently in patients taking bisacodyl: three days after injection 22% compared with 59%; five days after injection 23% compared with 35%. As bisacodyl acts only on the colon and does not disturb the enterohepatic circulation of cholesterol or bile acids, it is ideal for use with a tracer of cholesterol metabolism.