Real-Time Monitoring of Contact Impedance From Multiple Electrode–Scalp Interfaces During Cerebral Electrical Impedance Tomography

Abstract

Electrical impedance tomography (EIT) is a promising medical technique for monitoring brain injury through the reflection of electrical impedance changes in internal brain tissues. However, the contact impedances at the electrode-scalp interfaces can still notably affect the EIT accuracy. Hence, we propose a method for real-time monitoring the multi-channel contact impedances of cerebral EIT using a reference electrode attached close to the head vertex. This method allows to approximate inter-channel differences and changes over time of multi-channel contact impedances. The experimental results on 36 volunteers show that the maximum relative inter-channel difference obtained from 16 disposable surface electrodes reaches 18.7%, and the maximum relative change over time reaches 19.2%. The proposed method can assist clinicians in real-time monitoring of contact conditions from the multiple electrode-scalp interfaces during the clinical application of the cerebral EIT.

Real-Time Detection of Hemothorax and Monitoring its Progression in a Piglet Model by Electrical Impedance Tomography: A Feasibility Study

“…Moreover, the contact impedance often changes with time due to various inevitable factors such as perspiration, temperature change, patient movement, and manipulations by clinical staff [40]. Additionally, it is difficult to precisely measure the electrode-skin contact impedance of exciting electrodes [41]. Thus, the measured voltages are deducted when they are measured on electrode pairs that comprise one of the exciting electrodes, i.e., j ≠ 1, 8, 9, 16.…”

Suppressing interferences of EIT on synchronous recording EEG based on comb filter for seizure detection

“…Plus, it is portable, which enables continuous bedside monitoring of various physiological and pathological process. EIT has already been used successfully in breast cancer detection (25,26) and lung (27,28), gastric (29), brain function imaging (30,31), and in many other medical areas. It could also be used to image impedance changes related to blood flow (32).…”

An Improved Algorithm GVSPM-F for Electrical Impedance Tomography

“…Compared to CT (computed tomography) and MRI (magnetic resonance imaging), EIT has its unique advantages of non-invasive, simple structures, fast imaging speed, no radiation, portable and low price. EIT has been applied in many fields such as industrial process monitoring [1]- [3], geophysical exploration [4]- [6], and biomedical diagnosis [7]- [12]. However, the image spatial resolution of EIT is limited by the complex manner in which the probing field interacts with the measured field ('soft-field' effects).…”