Noninvasive and Quantitative Intracranial Pressure Estimation Using Microwave Technique

The circulation of cerebrospinal fluid (CSF) and interstitial fluid through periarterial spaces, brain parenchyma, and perivenous regions is regulated by arterial and tissue pulsatility, directly influencing intracranial pressure (ICP). Disruptions in this glymphatic function are associated with ICP fluctuations and may contribute to neurological decline. Despite its clinical importance, a reliable, non-invasive, and continuous method for ICP monitoring is still lacking. This study presents a practical microwave-based technique for fully non-invasive and continuous assessment of ICP. The designed microwave sensors are thin, small, planar, and lightweight, optimized for both sensitivity and anatomical compatibility. The sensors are tested on a realistic human head phantom model specifically developed for this study. A quantitative method based on advanced signal attributes: minima of antenna response, Area Under the Curve (AUC), Differential Multi-Static-Data Matrix (DMDM), Root Mean Square Multi-Static-Data Matrix (RMSMDM), and Group Delay Distortion (GDD) is devised to capture variations in the measured signal corresponding to changes in ICP. Multiple measurement trials demonstrate that the system can detect small changes in ICP with high accuracy. The estimated ICP values correlate strongly with ground-truth measurements obtained via invasive pressure sensors.