טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentBiron Galit
SubjectCerebral Blood Flow-Model
DepartmentDepartment of Biomedical Engineering
Supervisors Dr. Jean Francois Soustiel
Professor Emeritus Uri Dinnar (Deceased)
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Abstract

Background- The brain is exquisitely sensitive to reductions in blood flow. Severe reductions can lead to morphological tissue damage. The increase of intracranial pressure is the main cause for impairments in cerebral blood flow, especially in patients who suffer from brain trauma.

Purpose-Since the internal carotid artery supplies 80% of the cerebral blood flow, it is tempting to assume that pathologies that impair the cerebral blood flow will be reflected in its flow parameters. Hence the aim of this study was to evaluate the changes occurring during increased intracranial pressure by measuring flow parameters at the internal carotid artery in a physical model that simulate the clinical state.

Methods- We design a model that based on a pulsatility pump set to provide a physiological waveform through set of C-flex tubes at perfusion pressure of  130/90 mmHg.

The tubes simulate the vessels before entering the cranium: common carotid artery, internal carotid artery and the external carotid artery. Sealed bath simulate the cranium. In the bath we used tubes with high resistant and low resistant that simulates the transformation from the arteries to the veins. In order to simulate the pathology of raised intracranial pressure we compressed air to the bath. Perfusion pressure and bath pressure were continuously monitored by a 25-gauge needle connected to a pressure transducer. The parameters that we measured were flow velocity, pulsatility index, shear rate and flow. We used a new angle-independent ultrasonic device for assessment of flow.

Conclusions-Our model results were compatible with those of previous clinical reports so it seems relevant. From the results it seems that according the work hypothesis the alteration at the intracranial pressure are reflected at the internal carotid artery. The internal carotid artery is a convenient and simple site for monitoring the cerebral blood flow. From the result it seems that shear rate and blood flow velocity changes with a good correlation with the raising intracranial pressure.