Perfusion indices used in renal scintigraphy were adapted to captopril
-enhanced renal scintigraphy in order to determine if these parameters
have any value in differentiating patients with renovascular hyperten
sion (RVH) from normal subjects. Regions of interest (ROIs) were chose
n over the aorta and kidneys, and time-activity curves generated. The
ratio of integrated aortic counts to renal counts, from the time of in
jection to arterial peak, was calculated. The difference in the value
of this index between captopril and basal scintigraphies was -17 +/- 1
2 and -16 +/- 13 for the right and left kidneys, respectively; in the
group of patients with essential hypertension, whereas in the patients
with renovascular hypertension, these values were 24 in the stenotic
and 14 in the non-stenotic kidney. This parameter is useful for separa
ting patients with RVH from normal subjects.