[Urodynamic fundamentals, flow curve and urethral echo-Doppler. (Calculation of the urination strength and spectral power].

Objectives: We present the calculation of two parameters of practical interest for the urologists, which help to understand bladder phenomena. They are the real (total) power developed during micturition, and the spectral power of the flow curve, considered this as a finite time discrete signal.

Methods: We use Doppler ultrasound to calculate the propelling power of the urine towards the exterior.

[Urodynamics foundations: contractile potency and urethral doppler].

Objectives: To calculate the bladder softening factor, elastic constant and contractile potency.

Methods: For the analysis we considered bladder behavior like that of a spring. See articles 1 and 2 published in this issue.