الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
Obstructive uropathy is a problem that should be solved as early as possible to prevent further detei ioration of the kidney function, hence the importance of early diagnosis with a reliable, non invasive, easy to do ,and inexpensive tool to distinguish anatomic changes in the upper urinary tract from true obstruction that jeopardize the renal function.
In this study, we tried to evaluate obstructive uropathy with Doppler ultrasonography using the resistive index, and the delta resistive index so that the clinical application of this new tool can be tested as compared to other gold standard techniques.
Between 2000 and 2004 , 88 patients with suggested obstructive uropathy as well as 38 normal individuals were studied with Doppler ultrasonography. For accuracy a number of exclusion criteria and prerequisite factors have been decided
Positive cases for obstruction using Doppler parameters were compared with findings of intravenous urography ,diuretic renography and real time ultrasonography and the sensitivity and specificity of the Doppler test were calculated.
For more precise evaluation we divided the group positive. for obstruction into mildly ,moderately and severely obstructed and we calculated the sensitivity and specificity in each group.
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We found an overall sensitivity of 78.9% and specificity of 87.5%,we found also that the sensitivity and specificity increased markedly in the moderate and severe obstruction than the mild obstruction.
We found also in this study that the resistive index value was not related to age or sex and its value is not also dependent on whether the cause of obstruction is in the upper or lower urinary tract.
Also, we realized that the resistive index in solitary kidneys can not be relied upon to diagnose obstruction as it is usually elevated for reasons other than obstruction.
This study also revealed the importance of the resistive index ratio IRIRI,calculated to diagnose obstruction in children as suggested by Patti et al [2001] .
We recorded also the different difficulties that one may encounter during application of Doppler in the diagnosis of obstructive uropathy ,such as atrophic parenchyma, obesity, renal colic etc..
We conclude from this study that the Doppler parameters namely the resistive index,the delta resistive index and resistive index ratio can be used reliably in the diagnosis and follow up of obstructive uropathy. However, the sensitivity may be diminished in many conditions .For example in acute obstruction , renal colic, intake of NSAID and other conditions.
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We found many factors that may increase the value of Doppler parameters in obstructive uropathy. The application of the diuretic Doppler technique ,increase the sensitivity of the test and eliminate the equivocal results.
Unilateral obstruction is more accurately diagnosed with Doppler than bilateral obstruction because in unilateral obstruction, the delta resistive index calculation increase the accuracy of the test.In addition In solitary kidney the test may not be useful unless a value other than 0.7 is assumed.
The interaction of numerous variables affects the final resistive index results and , thus the studies must standardize ambient conditions, the measuring techniques, and the temporal relationships before any conclusion is given.
Standardizing the resistive index and delta resistive index threshold values may also facilitate comparison among various studies and therefore they are highly recominended.We recommend also further studies with a larger number of patients especially in cases with acute obstruction ,transplanted kidneys and cases associated with hypertension.
However, we conclude that Doppler is a non invasive inexpensive ,easy to perform, technique that can be used reliably in the diagnosis and follow up of obstructive uropathy.Its major advantage is that it can be used as alternative to other more invasive tools in cases such as pregnancy
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children, renal impairment ,and allergy to contrast.Its major disadvantages is the poor sensitivity in acute obstruction ,its unreliability in solitary kidneys and the need for complementary tests ,diuretic Doppler ,for exampie,in equivocal cases.