A Novel Technique for Simulating Transcranial Doppler Examinations In Vitro

Abstract

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.

Volumetric Intraoperative Brain Deformation Compensation: Model Development and Phantom Validation

“…Audette et al developed a phantom using Polyvinyl Alcohol Cryogel, which can change elasticity based on the number of freeze-thaw cycles used while curing [3]. As an alternative to these materials, several groups have used Dow Corning Sylgard 527 Silicone Dielectric Gel (Dow Corning, Midland, MI) for physical brain modeling in applications including tracking intraoperative brain deformation [38], assessing head trauma sustained from automobile accidents or other brain injuries ([7], [8], [9], [24], [30], [56], [57]), or development of a training system for transcranial doppler examinations [20]. In previous investigations, this silicone gel has been show to be similar to brain in oscillatory shear and stress relaxation properties, sensitivity to projectile velocity, and ductile response ([23], [56], [57]).…”