title: Captopril renography and the relevance of abnormal but bilateral identical curves in the diagnosis of renal artery stenosis.
abstract: BACKGROUND
  Captopril renography (CR) has been shown to improve the effectiveness of renal scintigraphy in renovascular hypertension, by inhibiting angiotensin-converting enzyme. CR is particularly sensitive and specific in unilateral renal artery stenosis (RAS), but results in patients with bilateral RAS are less favourable. The aim of this study was to investigate the meaning of abnormal but identical renographic curves in the diagnosis of RAS.
  
  
  METHODS
  One hundred and fifty-eight patients clinically suspected for renovascular hypertension underwent CR, using 50 MBq (99)Tc(m)-mercaptoacetyltriglycine ((99)Tc(m)-MAG(3)), prior to performing renal angiography. CR was performed 1 h after captopril administration. Renograms were analysed according to the consensus criteria. All patients underwent angiography, considered as the "gold standard" in the detection of the presence of RAS (stenosis >50% was defined as significant). All kidneys were categorized into three groups, scintigraphically as well as angiographically: no stenosis, unilateral stenosis and bilateral stenosis.
  
  
  RESULTS
  Out of 158 patients 100 (63%) showed a RAS on angiography (58 (37%) unilateral, 42 (26%) bilateral). The sensitivity and specificity of CR evaluated by patient was 83% and 75%, respectively. Thirty patients with completely identical curves were identified, 21 patients with normal curves and nine patients with abnormal identical curves. All but one patient showed no RAS on the angiogram. In this single patient a unilateral stenosis was found.
  
  
  CONCLUSIONS
  Identical curves on the renogram generally suggest no RAS and are probably due to intrinsic parenchymal disease.
authors.affiliation: Department of Nuclear Medicine, University Hospital Utrecht, Heidelberglaan 100, 3580 GA Utrecht, the Netherlands. hbalink@azu.nl
authors.forename: H
authors.initials: H
authors.lastname: Balink
authors.forename: I J
authors.initials: IJ
authors.lastname: Mertens
authors.forename: H
authors.initials: H
authors.lastname: Stevens
authors.forename: P P
authors.initials: PP
authors.lastname: van Rijk
authors.forename: J J
authors.initials: JJ
authors.lastname: Beutler
authors.forename: J M
authors.initials: JM
authors.lastname: De Klerk
mesh_terms: D000328:Adult; D000368:Aged; D002216:Captopril; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011866:Radioisotope Renography; D012078:Renal Artery Obstruction / Q000000981:diagnostic imaging*
chemical_list: D002216:Captopril