[Echography and pulsed Doppler of the arteries of the renal parenchyma in obstructive syndromes and dilatation of the excretory cavities of the kidney].

Ultrasonography is highly effective in diagnosing pyelocalyceal dilatation. Confirming the distension of these collecting structures, indicating probable obstruction, is more difficult since the degree of dilatation does not always correspond to the degree of distension. Renal studies were performed in 244 patients including 51 patients with dilation or renal obstruction. Doppler ultrasonography was used to measure the Pourcelot's resistive index of arcuate and interlobar arteries for each kidney. Results demonstrate: 1) for healthy patients the average vascular resistive index is 0.54 +/- 0.02 (minimum 0.48 +/- 0.02, maximum 0.60 +/- 0.02). 2) in cases of acute obstruction, this resistive index for pathologic kidney is elevated greater than 0.7. The difference in resistive indices between the pathologic and contralateral kidney was greater than 0.10. 3) in the patients with intermittent junctional syndromes when an intravenous furosemide test is used, there is an increase in the resistive index. 4) in case of chronic obstruction well tolerated, the increase in resistive index is moderate. If there is an acute deterioration, the resistive index become greater than 0.8. Concurrent abnormalities which affect only one kidney (pathology of the renal hilum, tumoral syndromes) may make it difficult to interpret certain results. Ultrasonography together with Doppler scanning may be in certain cases a reasonable alternative with IVP.