Electromagnetic resonant sensor patch for detection of fluid volume shifts within intracranial space

Abstract

Elevations in intracranial pressure (ICP) can result in a number of neurological complications and even death in patients who have had stroke, traumatic brain injury, or have undergone neurosurgical or neurological treatments. These complications can include cerebral hemorrhage, stroke, and irreparable brain damage. The current gold standard in measuring ICP requires implanting an intraventricular catheter into the patient’s skull, requiring invasive surgery and creating unnecessary health risk. Noninvasive methods are also available, but require highly specialized equipment, such as magnetic resonance imaging (MRI), computed tomography (CT), and transcranial Doppler ultrasonography (TCD). These methods are limited to a clinical setting, which hinders their use as a point-of-care technology. This study focuses on developing a point-of-care electromagnetic resonant sensor that can detect a shift in intracranial fluid volume, and then utilize this volume change to estimate pressure. The experimental protocol has been approved by the Institutional Review Board (IRB) of Wichita State University. The electromagnetic resonant sensor is unique in comparison to conventional monitoring systems because it is not made up of electrical components, connections, or batteries. Instead, this biomedical sensor uses a combination of radio frequency waves (RF waves), electromagnetic fields, and a Vector Network Analyzer (VNA) to measure and record physiological parameters that would otherwise require invasive or highly technical methods to detect. In this study, a fluid volume shift was induced by reclining a human subject past horizontal using a commercial grade inversion table. A bio-fluid shift was successfully detected and recorded using the sensor and was validated against TCD measurement calculations. The results suggest that the sensor patch may be capable of measuring intracranial pressure shifts in a point-of-care manner eliminating the need for specialized training and invasive equipment.