TUTCRIS - Tampereen teknillinen yliopisto


Biotelemetric wireless intracranial pressure monitoring: an in vitro study



JulkaisuInternational Journal of Antennas and Propagation
DOI - pysyväislinkit
TilaJulkaistu - 5 marraskuuta 2015
OKM-julkaisutyyppiA1 Alkuperäisartikkeli


Assessment of intracranial pressure (ICP) is of great importance in management of traumatic brain injuries (TBIs). The existing clinically established ICP measurement methods require catheter insertion in the cranial cavity. This increases the risk of infection and hemorrhage. Thus, noninvasive but accurate techniques are attractive. In this paper, we present two wireless, battery-less and minimally invasive implantable sensors for continuous ICP monitoring. The implants comprise ultra-thin (50 µm) flexible spiral coils connected in parallel to a capacitive microelectromechanical systems (MEMS) pressure sensor. The implantable sensors are inductively coupled to an external on-body reader antenna. The ICP variation can be detected wirelessly through measuring the reader antenna’s input impedance. This paper also proposes a novel implant placement to improve the efficiency of the inductive link. In this study, the performance of the proposed telemetry system was evaluated in a hydrostatic pressure measurement setup. The impact of the human tissues on the inductive link was simulated using a 5-mm layer of pig skin. The results from the in vitro measurement proved the capability of our developed sensors to detect ICP variations ranging from 0 to 70 mmHg at 2.5-mmHg intervals.