Duplex-sonography and color-Doppler evaluation of renal artery stenosis--angiographic correlation.
Echo Doppler has been used in 22 patients with suspected renovascular hypertension (RVH) to detect stenosis or occlusion of the renal artery. In 12 cases duplex Doppler technique was used and in 10 color Doppler. The Doppler examination was always performed before angiography which was considered the reference gold-standard. Using duplex Doppler the diagnosis of RVH was based on qualitative (spectral analysis of the waveform) and semi quantitative parameters (resistive index). With color Doppler two other quantitative parameters were used, peak systolic frequency shift at the level of the stenosis and stenosis index. The color Doppler has shown a better specificity and a better PPV. The sensitivity of the color Doppler was comparable to that of the duplex scanner (89% and 90%, respectively). Further studies are necessary in order to define the diagnostic parameters, the reproducibility and the intra- and interobserver reproducibility. The technological progress may in the future reduce the difficulty and the time of examination.