Investigation of urine transport in the ureter of the pig by x-ray videodensitometry. I. The effect of increasing diuresis on velocity and rhythm of contractions: relationship between pressure wave and urine bolus.

The flow rate is the decisive parameter of ureteric function. The frequency and the velocity of the contraction waves can be measured by X-ray videodensitometry without having to touch the ureter. The relationship between flow rate (milliliters per minute) and wave velocity (millimeters per second) is investigated in the pig ureter. It can be demonstrated that the wave velocity is a quadratic function of the perfusion. The graphic representation of this function corresponds ot a parabolic curve. The relationship between the bolus and the pressure wave is analyzed and it is shown that the time lag between the rear end of the bolus and the pressure peak is independent of the wave velocity. The theoretical ureter model of Weinberg is experimentally confirmed by simultaneous manometry and videodensitometry.