title: Basic characteristics of implantable flexible pressure sensor for wireless readout using MRI.
abstract: Measuring the local pressure in blood vessels is valuable in the postoperative monitoring of aneurysms. However, implanting a conventional pressure sensor equipped with power and signal cables causes difficulties during the operative procedure and carries a risk of infection after the implantation. In this study, we developed a wireless, implantable, and flexible pressure sensor. A magnetic resonance imaging (MRI) system reads out the sensor output. The proposed wireless sensor is based on an LC resonant circuit with a spiral coil and a pressure-sensitive capacitor. The pressure-dependence of the capacitance affects the magnetic field produced by the spiral coil, changing the magnetization of the nearby sample that can be observed as a signal variation by MRI. We fabricated a prototype sensor using a capacitor with a silicone elastomer as the dielectric and a spiral coil made of gold. The maximum change in the capacitance was 8% under an external pressure of 20 kPa. A change in the thickness of the dielectric elastomer caused the capacitance to change, resulting in a signal variation detectable by MRI.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Nakamura
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Inoue
authors.forename: Dongmin
authors.initials: D
authors.lastname: Kim
authors.forename: Naoji
authors.initials: N
authors.lastname: Matsuhisa
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yokota
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Sekitani
authors.forename: Takao
authors.initials: T
authors.lastname: Someya
authors.forename: Masaki
authors.initials: M
authors.lastname: Sekino
mesh_terms: D001794:Blood Pressure; D015924:Blood Pressure Monitors; D025802:Electric Capacitance; D006801:Humans; D008279:Magnetic Resonance Imaging; D008991:Monitoring, Physiologic / Q000295:instrumentation; D019736:Prostheses and Implants; D059015:Wireless Technology