Noninvasive real-time assessment of intracranial pressure after traumatic brain injury based on electromagnetic coupling phase sensing technology

Background: To investigate the feasibility of intracranial pressure (ICP) monitoring after traumatic brain injury (TBI) by electromagnetic coupling phase sensing, we established a portable electromagnetic coupling phase shift (ECPS) test system and conducted a comparison with invasive ICP. Methods: TBI rabbits' model were all synchronously monitored for 24 h by ECPS testing and invasive ICP. We investigated the abilities of the ECPS to detect targeted ICP by feature extraction and traditional classification decision algorithms. Results: The ECPS showed an overall downward trend with a variation range of - 13.370 +/- 2.245 degrees as ICP rose from 11.450 +/- 0.510 mmHg to 38.750 +/- 4.064 mmHg, but its change rate gradually declined. It was greater than 1.5 degrees/h during the first 6 h, then decreased to 0.5 degrees/h and finally reached the minimum of 0.14 degrees/h. Nonlinear regression analysis results illustrated that both the ECPS and its change rate decrease with increasing ICP post-TBI. When used as a recognition feature, the ability (area under the receiver operating characteristic curve, AUCs) of the ECPS to detect ICP >= 20 mmHg was 0.88 +/- 0.01 based on the optimized adaptive boosting model, reaching the advanced level of current noninvasive ICP assessment methods. Conclusions: The ECPS has the potential to be used for noninvasive continuous monitoring of elevated ICP post-TBI.