Diuresis renography and simultaneous renal pelvic pressure in hydronephrosis

We investigated 23 hydronephrotic kidneys in 10 male and 12 female patients (mean age 32 years) with diuresis renography and simultaneous, continuous renal pelvic pressure measurement to compare isotope washout with pelvic pressure changes. No correlation was found between these 2 parameters. Of the kidneys 14 were investigated further by a standard Whitaker pressure flow study. There was only a poor correlation between diuresis renography and the pressure flow study, and between the pelvic pressures during perfusion and forced diuresis. Impaired renal uptake fraction signifying the degree of obstructive nephropathy did not correlate with the dynamic tests. An Anderson-Hynes pyeloplasty was done in 19 patients. There was no correlation between the presence of organic stenosis or external compression and the outcome of the diagnostic tests. We concluded that the currently used diagnostic procedures for hydronephrosis generally are insufficient to discriminate between significant and nonsignificant obstruction.