RESUMO
Objective To evaluate the diagnostic value of velocity parameters of Tardus-Parvus for the detection of renal artery stenosis ( RAS) ( diameter reduction ≥50%) and to determine the useful cutoffs for these parameters .Methods A study group was composed of 221 renal arteries that were detected Tardus-Parvus by color Doppler flow imaging and were referred to abdomino-aorto-re-nal arteriography afterwards .Five Doppler parameters including the peak systolic velocity ( PSV ) , end-diastolic minimum velocity (EDV), resistance index (RI), acceleration time (AT), and accelerated velocity (AC) from each location including renal aorta ( MRA) , segmental artery ( SRA) , interlobar artery ( IRA) , and arcuate artery ( ARA) were archived and compared among the differ-ent groups .Renal artery angiography showed arterial canon reduced 50% or higher RAS .Arteries were considered stenosed on renal arteriography if there was a diameter reduction of greater than 50%.Statistical analysis to determine the best parameter for predicting a RAS was performed with the receiver operating characteristic ( ROC) curves.The sensitivity, specificity, and negative and positive predicting values at various cutoffs were calculated .Results Renal artery stenosis degree was less than 50% in 16 cases, 50%~99%in 197 cases, completely occluded in 2 cases, and no stenosis in 6 case by renal arteriography .For RAS with inner diameter re-duction of 50%or more, the ROC curve analysis showed renal artery flow velocity had a good sensitivity and specificity , 50%~99%of the RAS had optimal threshold value in PSV 20 cm/s, EDV 10 cm/s, RI 0.50, AT 0.09 s, and AC 1.5 m/s2.Conclusions Tardus-Parvus had high specificity and sensitivity for diagnosis of stenosis rate in more than 50% of the RAS, low sensitivity for the narrow degree in 0~49%, and no clinical value for the renal artery occlusion .