Non-invasive investigation of normal individual ureteric activity in man

This study was designed to investigate non-invasively human ureteric function between individuals and with increasing diuresis, using the radioisotope compressed image technique. Five normal males underwent fast frame renography with ureteric spindle imaging in dehydrated and hydrated states, urine production being measured in each individual for each scan. Urine flow rates and renographic parameters demonstrated that each ureter carried more urine in the hydrated state. The velocity at which individual boluses passed down the ureter was constant for each ureter and did not change with diuresis. The ureteric peristaltic rate showed wide individual variation between ureters in the same subject, but fell within what is becoming accepted as the "normal range" of < 4 urine boluses per minute. Some ureters accommodated an increase in urine flow by an increased peristaltic frequency, some showed no change and others showed a decreased frequency. In those ureters in which there was no change, or a decrease in peristaltic frequency with diuresis, the increased urine flow must have been handled by increases in bolus volume. Thus increases in ureteric urine flow in man are accommodated by changes in both peristaltic frequency and bolus size. The results are discussed in relation to previous studies which used invasive techniques.