Continuous recording of blood vessel diameter in vitro during perfusion with regulated pressure patterns.

A system is described for continuously measuring blood vessel diameter during perfusion with constant pressure or with fluctuating pressure of preselected patterns. An electromechanical modulator controls the inflow of the perfusion solution, keeping the actual pressure in the blood vessel at a preselected value via a feed-back circuit. The outer diameter of the vessel can be simultaneously and continuously recorded at several chosen positions with the aid of a multichannel video angiometer. The whole set-up is suitable for small vessels of a diameter reaching down to 0.5 mm.