A novel technique for simulating transcranial doppler examinations in vitro

Abstract

The left internal carotid artery of a cadaveric head was injected with a methyl methacrylate casting resin. The cast of the vessels of the Circle of Willis was used to construct an artificial arterial system from Tygon R3603 tubing. Sylgard 527 elastomer gel was used to replace the intracranial contents. Sylgard 184 was used to replicate the extracranial tissues. The model was perfused with a fluid consisting of sephadex particles and glycerine, which approximates normal blood characteristics. Physiologically accurate fluid flow was achieved using a custom designed computer controlled syringe pump which could deliver normal or pathological flow profiles as required. Age and sex matched control data were compared with data obtained from the model system using a Transcranial Doppler scanner. The results showed that a close approximation between the artificial and in vivo flow patterns could be achieved by manipulation of the flow profile.