Resistive index (RI) calculation on Doppler tracing of intrarenal arterial blood flow is a sensitive method for the early diagnosis of obstructive uropathy. However, the RI is not specific and can increase in a number of other conditions, e.g., old age, circulating endogenic factors or drugs, other nephropathies. The authors investigated RI usefulness and accuracy by measuring it both before and after the radiologic treatment of acute urinary obstruction in 21 patients, 9 of whom had chronic renal failure due to other causes, i.e., hypertension, diabetes and chronic pyelonephritis. The clinical conditions of the patients limited the feasibility of RI measurements before and after nephrostomy to 66%. In 22 kidneys in 17 patients examined before nephrostomy, the RI ranged 0.63 to 0.93 (mean: 0.80); when the obstruction was unilateral, the RI was always higher than in the contralateral kidney. In 25 kidneys in 18 patients examined after nephrostomy, the mean RI value was 0.68 (15% lower than before). Taking 0.7 as the cut-off value, RI sensitivity in detecting acute urinary obstruction was high (about 90%), while its specificity was low (about 50%); specificity increased (to about 80%) when other concomitant causes of increased intrarenal arterial resistance, e.g., other vascular or parenchymal nephropathies, were not considered. In some cases, the method was also useful in excluding the presence of recurrent obstruction after ureteral stent removal. In conclusion, Doppler US values of intrarenal arterial perfusion are indicative of acute urinary obstruction when they can be compared with those from the contralateral healthy kidney or when they can be measured, in the same patient, before and after decompressive nephrostomy. In other cases, other nephropathies and some technical limitations must be considered.
[Doppler ultrasonography of the intrarenal arteries before and after radiologic treatment in obstructive uropathy]
VELTRI, Andrea;
1995-01-01
Abstract
Resistive index (RI) calculation on Doppler tracing of intrarenal arterial blood flow is a sensitive method for the early diagnosis of obstructive uropathy. However, the RI is not specific and can increase in a number of other conditions, e.g., old age, circulating endogenic factors or drugs, other nephropathies. The authors investigated RI usefulness and accuracy by measuring it both before and after the radiologic treatment of acute urinary obstruction in 21 patients, 9 of whom had chronic renal failure due to other causes, i.e., hypertension, diabetes and chronic pyelonephritis. The clinical conditions of the patients limited the feasibility of RI measurements before and after nephrostomy to 66%. In 22 kidneys in 17 patients examined before nephrostomy, the RI ranged 0.63 to 0.93 (mean: 0.80); when the obstruction was unilateral, the RI was always higher than in the contralateral kidney. In 25 kidneys in 18 patients examined after nephrostomy, the mean RI value was 0.68 (15% lower than before). Taking 0.7 as the cut-off value, RI sensitivity in detecting acute urinary obstruction was high (about 90%), while its specificity was low (about 50%); specificity increased (to about 80%) when other concomitant causes of increased intrarenal arterial resistance, e.g., other vascular or parenchymal nephropathies, were not considered. In some cases, the method was also useful in excluding the presence of recurrent obstruction after ureteral stent removal. In conclusion, Doppler US values of intrarenal arterial perfusion are indicative of acute urinary obstruction when they can be compared with those from the contralateral healthy kidney or when they can be measured, in the same patient, before and after decompressive nephrostomy. In other cases, other nephropathies and some technical limitations must be considered.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
