Evaluating and Reducing the Influence of Scalp Dehydration in the Monitoring of Intracranial Dehydration Using Electrical Impedance Tomography

Dehydration treatment is commonly applied to treat intracranial hypertension. We previously utilized electrical impedance tomography (EIT) for noninvasively monitoring the efficacy of dehydration treatments and found it could provide references for the rational use of dehydrating drugs. In addition to brain tissues, scalp undergoes dehydration and can cause impedance changes, which may hamper the monitoring results of intracranial dehydration through EIT. To address this problem, we first conducted simulation and animal experiments to evaluate the impact of scalp dehydration on the monitoring results of EIT during dehydration treatments. With the priori of the spatial distribution of brain structures and the statistical results of the contribution of scalp dehydration to the intracranial reconstructed values of the EIT images obtained from animal experiments, we then proposed a weighting algorithm to reduce the impact of scalp dehydration. The experimental results showed that scalp impedance changes would to some extent reduce the accuracy of EIT in imaging intracranial resistive perturbation and account for 16.7% in overall changes of EIT signal. With the modified algorithm, 69.6% of reconstructed values of scalp dehydration in EIT images were eliminated. And the image contrast (IC) of reconstructed EIT images was improved by 21.0%. Therefore, we conclude that scalp dehydration influences the accuracy of EIT in reflecting intracranial dehydration and our proposed method can reduce the impacts of scalp dehydration.