Purpose: To evaluate the differences among five representative and potentially useful Doppler parameters in the diagnosis of the three common types of renal artery stenosis (RAS).
Materials and Methods: Five Doppler parameters including renal peak systolic velocity (RPSV), renal-aortic ratio (RAR), renal-interlobar ratio (RIR), acceleration time (AT), and resistant index (RI) were measured in 221 patients before arteriography. Differences between the groups of patients with various clinical causes of RAS were analyzed by chi-squared test. One-way ANOVA was used to compare the means between different groups. The optimal cutoff value was determined with the maximum sum of sensitivity and specificity.
Results: Of the 442 renal arteries (main and accessory renal arteries) demonstrated at arteriography, 214 were normal or stenosed less than 50%, 204 moderate stenoses (50%-99%), and 24 occlusions. RPSV and AT were not significantly different while RIR, RAR and RI were significantly different between the atherosclerotic and non-atherosclerotic RAS groups. The optimal cutoff values of the RPSV, RAR, RIR and RI for the atherosclerotic and non-atherosclerotic groups were much different (170cm/s versus 200cm/s, 2.5 versus 1.9, 5.1 versus 6.5, 0.57 versus 0.50, respectively), but those of the AT were the same (51 ms).
Conclusion: In the case of RAS (diameter reduction ≥50%), it is advised to establish separate cutoff values of RPSV, RAR, RIR, and RI according to atherosclerotic and non-atherosclerotic RAS, but the same cutoff value of AT ≥50ms can be applied to the three common types of RAS.