title: Duplex Doppler sonography of transplant renal artery stenosis.
abstract: OBJECTIVE
  The aim of this study was to evaluate the accuracy of duplex Doppler sonography in diagnosing transplant renal artery stenosis (TRAS) and to determine which parameter is the most reliable for making that diagnosis.
  
  
  METHODS
  Over a 3-year period, we sonographically evaluated patients who were referred for investigation of possible TRAS. We investigated the following parameters: peak systolic velocity (PSV) in the external iliac and renal arteries, acceleration time and acceleration in the intrarenal arteries, acceleration time in the renal artery, resistance index, and the ratio of the PSVs in the renal and external iliac arteries. We also used MR angiography and digital subtraction arteriography to verify the degree of stenosis. After the evaluations, the patients were classified into 2 groups, 1 with and the other without significant stenosis (> 50% narrowing of the lumen) on digital subtraction arteriography. We also included a control group of patients who had undergone renal transplantation at least 6 months before, had had a good course after transplantation, had a diastolic blood pressure of 90 mm Hg or less, and were taking a maximum of 1 antihypertensive drug.
  
  
  RESULTS
  Our study population consisted of 22 patients suspected to have TRAS (10 without and 12 with confirmed significant stenosis) and 19 control patients. We found statistically significant differences between the mean values of these 3 groups except for the PSV in the iliac artery and the resistance index in the intrarenal arteries. The most accurate parameters to use in diagnosing TRAS were an acceleration time of 0.1 second or higher in the renal and intrarenal arteries, a PSV of greater than 200 cm/second in the renal artery, and a ratio of PSVs in the renal and external iliac arteries of greater than 1.8.
  
  
  CONCLUSIONS
  Duplex Doppler sonography is an excellent method for screening patients suspected to have TRAS and can help select which of those patients should undergo digital subtraction arteriography.
authors.affiliation: Center of Imaging Science and Medical Physics, Faculty of Medicine of Ribeirão Preto, University of São Paulo, Avenida Bandeirantes 3900, Ribeirão Preto, São Paulo, Brazil 14048-900.
authors.forename: Ruth Helena
authors.initials: RH
authors.lastname: de Morais
authors.forename: Valdair Francisco
authors.initials: VF
authors.lastname: Muglia
authors.forename: Augusto Elias
authors.initials: AE
authors.lastname: Mamere
authors.forename: Tânia
authors.initials: T
authors.lastname: Garcia Pisi
authors.forename: Luciana Tanajura
authors.initials: LT
authors.lastname: Saber
authors.forename: Valmir Aparecido
authors.initials: VA
authors.lastname: Muglia
authors.forename: Jorge
authors.initials: J
authors.lastname: Elias
authors.forename: Carlos Eli
authors.initials: CE
authors.lastname: Piccinato
authors.forename: Clóvis Simão
authors.initials: CS
authors.lastname: Trad
mesh_terms: D000293:Adolescent; D000328:Adult; D015901:Angiography, Digital Subtraction; D001783:Blood Flow Velocity; D006801:Humans; D007083:Iliac Artery / Q000000981:diagnostic imaging; D016030:Kidney Transplantation / Q000009:adverse effects*; D018810:Magnetic Resonance Angiography; D008875:Middle Aged; D011446:Prospective Studies; D012078:Renal Artery Obstruction / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000209:etiology; D012680:Sensitivity and Specificity; D018616:Ultrasonography, Doppler, Duplex