title: Evaluation of renal artery stenosis with velocity parameters of Doppler sonography.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the accuracy of velocity parameters for the diagnosis of renal artery stenosis (RAS) with color Doppler sonography and to determine the optimal threshold values for these parameters.
  
  
  METHODS
  The study group was composed of 187 renal arteries, which were examined by color Doppler sonography and angiography. Four Doppler parameters, including the peak systolic velocities (PSVs) in the renal and interlobar arteries, the renal-aortic ratio, and the renal-interlobar ratio (RIR), were measured. Receiver operating characteristic curve analysis was performed to determine the optimal parameter. The sensitivity, specificity, and negative and positive predictive values at various threshold values were calculated.
  
  
  RESULTS
  Doppler sonographic examination was technically successful in 96% of renal arteries (180/187). The RIR was determined to be the best parameter. With threshold values of RIR greater than 5, PSV greater than 150 cm/s in the renal artery, renal-aortic ratio greater than 2, and PSV less than 25 cm/s in the interlobar artery, the sensitivity values were 88%, 81%, 70%, and 74%, respectively. An RIR greater than 5 and PSV less than 15 cm/s in the interlobar artery provided the optimal combination of parameters, with sensitivity and specificity of 91% and 87%, respectively.
  
  
  CONCLUSIONS
  The RIR is the best velocity parameter in the detection of RAS (> or =50%), and its best cutoff is 5. Valuing influencing factors of PSV in the renal artery will help reduce misdiagnosis. The combination of RIR greater than 5 and PSV less than 15 cm/s in the interlobar artery provides the best diagnostic efficiency of RAS.
authors.affiliation: Department of Ultrasonography, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Wangfujing, Beijing 100730, China.
authors.forename: Jian-Chu
authors.initials: JC
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Yu-Xin
authors.initials: YX
authors.lastname: Jiang
authors.forename: Qing
authors.initials: Q
authors.lastname: Dai
authors.forename: Sheng
authors.initials: S
authors.lastname: Cai
authors.forename: Ke
authors.initials: K
authors.lastname: Lv
authors.forename: Zhen-Hong
authors.initials: ZH
authors.lastname: Qi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012078:Renal Artery Obstruction / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D018608:Ultrasonography, Doppler