Peristalsis of the pyeloureter in pigs measured by videodensitometry.

The peristaltic activity of the upper urinary tract was investigated by means of a simple videodensitometric system. Through a transparenchymally placed catheter contrast medium was infused into the renal pelvis with perfusion rates increasing from 1 to 15 ml/min. Sequences of 3-5 min were recorded by means of a Siemens image amplifier on videotape for later analysis. Photodiodes were placed on the screen over the calyces, renal pelvis and ureter at a distance of 5 cm. An amplifying system and a UV recorder were used for registration. Peristaltic frequency, transmission velocity and average bolus volume were measurable in 8 out of 10 pyeloureteral units. Additionally, calyceal activity was detectable in one case. The tracings obtained by videodensitometry were reproducible and easy to analyse. Conversion of videorecordings to analogue signals for analysis might be a possible future clinical diagnostic method.