Intracranial Pressure Measurement System Based On Brain Impedance

Diseases such as hydrocephalus,cerebral hemorrhage and craniocerebral inflammation will all result in the increase of brain contents.Due to the approximate closed cranial cavity and strong rigidity,the increase of brain contents will lead to the gradual increase of intracranial pressure.This pathological phenomenon is called increased intracranial pressure in medical science.For a long time in intracranial pressure can lead to cerebral hernia,leading to respiratory failure,life threatening.In the process of increasing intracranial pressure,the change of brain content can lead to the change of brain impedance.Therefore,the measurement of brain impedance using bioimpedance technology can monitor the change of brain content and determine whether the intracranial pressure is increased or not,which is of great significance.Based on the basic principle of bioelectrical impedance measurement,the theory and key techniques of bioelectrical impedance measurement for intracranial pressure are studied in this paper.First,the electrical characteristics of biological cells and tissues and the relationship between intracranial pressure and electrical impedance were studied.Secondly,in order to estimate the change trend of intracranial pressure more accurately,the improved calculation method of intracranial pressure was studied.Based on the volume-pressure model,the modified amount was introduced in this method to reduce the error,and a solution was provided for the modeling of the whole process of intracranial pressure rise.Finally,design a set of intracranial pressure testing detection system,the whole system includes both excitation and detection module.The excitation source part includes a sinusoidal signal generator and a constant current source circuit.In the detection module,a high-performance voltage buffer circuit,differential amplifier,filter module,amplitude and phase discrimination circuit and other modules are designed to process the measurement signal,and a graphic display module is designed to display,analyze and store the measurement data.The standard resistance was measured by the intracranial pressure measuring system to test the accuracy and stability of the system.Brain impedance and intracranial pressure were measured under normal and high intracranial pressures.The experimental results show that the calculation method of intracranial pressure proposed in this paper has higher accuracy,and the designed system can correctly estimate the value and change trend of intracranial pressure...