Collaborative Hypertext of Radiology

captopril renal scan

In a kidney with a lesion proximal to the afferent arterioles (e.g. atherosclerotic plaquein the renal artery), reflex constriction of the efferent arteriole occurs through angiotensin system thus maintaining renal perfusion.

ACE inhibition prevents constriction of efferent arterioles. Therefore, the glomerular filtration rate is decreased in a kidney with afferent lesions and the renal scan looks WORSE.

Bottom line: renal scans appear WORSE with captopril administration if there is a lesion proximal to the afferent arterioles.

see: renal artery stenosis

Brian Funaki, MD - 6 February 1995
Last updated: 1 October 2013