[Doppler echography and color Doppler echography in the assessment of the vascular functional aspects of medical nephropathies].

This study was aimed at finding a Doppler parameter to distinguish, among medical nephropathies, the ones with glomerular from those with vascular or tubulointerstitial involvement. Therefore, 32 patients (20 men and 10 women, average age: 43 years, range: 10-77 years) with clinical and laboratory signs of medical renal disease were examined with color-Doppler US. The resistive index (RI, n.v. < 0.70), as calculated from the Doppler waveform signal was especially considered to assess eventual significant changes differentiating renal diseases according to the different kinds of involvement. RI values were compared with renal biopsy findings, creatininemia levels and clinical and laboratory variables as hematuria and proteinuria. Histology diagnosed 18 glomerulonephritis, 4 glomerulonephritis with interstitial involvement and 10 vascular and tubulointerstitial nephroses, with 1 tubular necrosis. Doppler US demonstrated a normal RI value in 17/18 patients with glomerulonephrosis (mean value: 0.59 +/- 0.05). In one case only, even though biopsy indicated the involvement of one glomerulus only (membranous GN II stage), RI was high--i.e., 0.79. In 4 patients with simultaneous glomerular and interstitial involvement, the mean RI value was 0.17 +/- 0.01. In the 10 cases of tubulointerstitial or vascular nephrosis, the RI was 0.83 +/- 0.07. As far as the correlation between creatininemia levels and RI is concerned, in 8 patients with high values (1.5-8 mg/dl), the mean RI was 0.72 +/- 0.08 and only a weak correlation was found between the RI and the renal failure degree as expressed by creatininemia levels. Therefore, the RI seems to be related more to the site of the disease in the renal field than to renal failure degree. Doppler US seems to be capable of characterizing medical nephrosis, distinguishing glomerular from vascular or tubulointerstitial involvement. In this application area, the combined use of Doppler and color-Doppler US allowed each examination to be performed in a relatively short time--i.e., 30 minutes on the average.