Imaging compatible electrodes for continuous electroencephalogram monitoring in the intensive care unit

Continuous electroencephalogram in the intensive care unit is increasingly recognized as an important diagnostic and prognostic tool in critically ill patients. Metal disc electrodes or subdermal needle electrodes are neither computed tomography nor magnetic resonance imaging compatible. Their frequent replacement required for imaging purposes is time consuming and contributes to scalp breakdown. We have developed and report on two new types of imaging compatible electrodes. The subdermal wire electrode and the silver-epoxy-coated conductive plastic electrode are magnetic resonance imaging, computed tomography, and angiogram compatible. Moreover, the subdermal wire electrode does not require any daily maintenance. The electrodes were used on a total of 24 intensive care unit patients (subdermal wire electrode = 20, conductive plastic electrodes = 4) who required continuous electroencephalogram. During an average of 62.2 +/- 44 hours of electroencephalogram recording, 54% of the patients underwent imaging procedures (nine magnetic resonance imagings, five computed tomographic scans, and two angiograms) of good quality without the need to remove/replace the electrodes. The continuous electroencephalogram revealed epileptogenic activity that was not detected on standard 20-minute recordings in 28% of patients screened, with electrographic seizures in 11%. These two types of imaging compatible electrodes offer definite advantages in clinical practice. The combined diagnostic information of continuous electroencephalogram and easy-to-plan imaging yields important results and improves the clinical management and treatment of intensive care unit patients.