SUSPECTED OBSTRUCTIVE PYELOCALIECTASIS - DOPPLER ULTRASONOGRAPHY COMPARED WITH DIURETIC RENAL SCINTIGRAPHY IN PROVEN CASES

OBJECTIVE: To compare Doppler ultrasonography with diuretic renal scin tigraphy in the differentiation of obstructive from nonobstructive pye localiectasis. PATIENTS AND METHOD: The authors reviewed the findings of Doppler ultrasonography and diuretic renal scintigraphy performed o ver a 3-year period for 27 pyelocaliectatic kidneys (17 obstructed and 10 unobstructed) in 20 individuals ranging in age from 19 to 88 years . The kidneys were classified as ''obstructed'' or ''unobstructed'' on the basis of the resistive index as calculated from Doppler ultrasono graphic results and as ''obstructed'', ''unobstructed'' or ''indetermi nate'' on the basis of the clearance half-time determined from scintig raphic findings. RESULTS: On the basis of scintigraphy, the obstructio n status was indeterminate in 12 of the 27 kidneys. The data were anal ysed for sensitivity and specificity in two ways, first by classifying the kidneys with indeterminate obstruction status as ''obstructed,'' and then by excluding them from the analysis altogether. In both situa tions, the differences in sensitivity and specificity between Doppler ultrasonography and scintigraphy were not statistically significant (c hi(2) test, p > 0.05). When the kidneys with indeterminate obstruction status were included in the obstructed category, the sensitivity and specificity of Doppler ultrasonography were 94% and 90% respectively a nd of scintigraphy 100% and 70% respectively; when the kidneys with in determinate obstruction status were excluded, the sensitivity and spec ificity of Doppler ultrasonography were 83% and 89% respectively and o f scintigraphy 100% and 78% respectively. CONCLUSIONS: These results s uggest that Doppler ultrasonography is comparable to diuretic renal sc intigraphy in the work-up of potential obstructive pyelocaliectasis. B ecause grey-scale ultrasonography is usually performed before scintigr aphy, a Doppler examination could be added at this stage, which might reduce the time necessary to establish the diagnosis.