The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform

Wang Kan - One of the best experts on this subject based on the ideXlab platform.

Leena Ukkonen - One of the best experts on this subject based on the ideXlab platform.

  • miniature coplanar implantable antenna on thin and flexible platform for fully wireless Intracranial Pressure Monitoring system
    International Journal of Antennas and Propagation, 2017
    Co-Authors: Waqas M A Khan, Elham Moradi, Toni Bjorninen, Lauri Sydanheimo, Y Rahmatsamii, Leena Ukkonen
    Abstract:

    Minimally invasive approach to Intracranial Pressure Monitoring is desired for long-term diagnostics. The monitored Pressure is transmitted outside the skull through an implant antenna. We present a new miniature (6 mm × 5 mm) coplanar implant antenna and its integration on a sensor platform to establish a far-field data link for the sensor readout at distances of 0.5 to 1 meter. The implant antenna was developed using full-wave electromagnetic simulator and measured in a liquid phantom mimicking the dielectric properties of the human head. It achieved impedance reflection coefficient better than −10 dB from 2.38 GHz to 2.54 GHz which covers the targeted industrial, scientific, and medical band. Experiments resulted in an acceptable peak gain of approximately −23 dBi. The implant antenna was submerged in the liquid phantom and interfaced to a 0.5 mW voltage controlled oscillator. To verify the implant antenna performance as a part of the ICP Monitoring system, we recorded the radiated signal strength using a spectrum analyzer. Using a half-wavelength dipole as the receiving antenna, we captured approximately −58.7 dBm signal at a distance of 1 m from the implant antenna which is well above for the reader with sensitivity of −80 dBm.

  • Characterization of 3-D Loop Antenna to Overcome the Impact of Small Lateral Misalignment in Wirelessly Powered Intracranial Pressure Monitoring System
    IEEE Transactions on Antennas and Propagation, 2017
    Co-Authors: Waqas M A Khan, Toni Bjorninen, Lauri Sydanheimo, Muhammad Rizwan, Yahya Rahmat-samii, Leena Ukkonen
    Abstract:

    This communication presents a 3-D loop antenna to overcome the impact of small lateral misalignment of the order of 2 mm between the inductively coupled antennas. This communication is a continuation of our previously reported work. In our previous work, we have successfully activated the Pressure Monitoring sensor and performed the Pressure readout for an Intracranial Pressure Monitoring application. The Pressure sensor was activated through wireless inductive near-field powering. Measurement showed that there was significant effect on Pressure readout accuracy due to small lateral misalignment between the inductively coupled antennas. In this communication, we demonstrate that the structural properties of a simple 3-D loop antenna help to overcome the Pressure readout error caused by small lateral misalignment. We present the design procedure, simulation results, and Pressure readout measurement of the proposed 3-D loop antenna. Moreover, the Pressure Monitoring system shows maximum improvement of 9 mmHg in Pressure readout accuracy with the proposed 3-D loop antenna.

  • Evaluation of an implantable passive sensor for wireless Intracranial Pressure Monitoring
    2015 IEEE International Symposium on Antennas and Propagation & USNC URSI National Radio Science Meeting, 2015
    Co-Authors: Mohammad H. Behfar, Elham Moradi, Toni Bjorninen, Lauri Sydanheimo, Leena Ukkonen
    Abstract:

    This paper proposes and evaluates a fully implantable passive sensor for minimally invasive Intracranial Pressure Monitoring. The sensor is inductively linked with an on-body reader coil to detect Pressure variations. Evaluation of the sensor proved the capability of highly linear Pressure measurement ranging from 0 to 70 mmHg at 5-mmHg intervals.

Tellen D Bennett - One of the best experts on this subject based on the ideXlab platform.

  • functional outcome after Intracranial Pressure Monitoring for children with severe traumatic brain injury
    JAMA Pediatrics, 2017
    Co-Authors: Tellen D Bennett, Peter E Dewitt, Tom Greene, Rajendu Srivastava, Jay Rivacambrin, Michael L Nance, Susan L Bratton, Desmond K Runyan
    Abstract:

    Importance Intracranial Pressure (ICP) Monitoring is a mainstay of therapy for children with traumatic brain injury (TBI), but its overall association with patient outcome is unclear. Objective To test the hypothesis that ICP Monitoring is associated with improved functional survival of children with severe TBI. Design, Setting, and Participants A propensity-weighted effectiveness analysis was conducted using 2 linked national databases with data from 30 US children’s hospitals from January 1, 2007, to December 31, 2012, on 3084 children with severe TBI. Clinical events including neurosurgical procedures were identified using validated computable phenotypes. Data analysis was conducted from September 1, 2016, to March 1, 2017. Exposure Placement of an ICP monitor. Main Outcomes and Measures A composite of hospital mortality, discharge to hospice, or survival with placement of new tracheostomy and gastrostomy tubes. Results Of the 3084 children in the study (1128 girls and 1956 boys; mean [SD] age, 7.03 [5.44] years), 1002 (32.4%) underwent ICP Monitoring, with substantial hospital variation (6% to 50% by hospital). Overall, 484 children (15.7%) experienced the primary composite outcome. A propensity approach using matching weights generated good covariate balance between those who did and those who did not undergo ICP Monitoring. Using a propensity-weighted logistic regression model clustered by hospital, no statistically significant difference was found in functional survival between monitored and unmonitored patients (odds ratio of poor outcome among those who underwent ICP Monitoring, 1.31; 95% CI, 0.99-1.74). In a prespecified secondary analysis, no difference in mortality was found (odds ratio, 1.16; 95% CI, 0.89-1.50). Prespecified subgroup analyses of children younger and older than 2 years of age and among those with unintentional and inflicted (intentional) injuries also showed no difference in outcome with ICP Monitoring. Conclusions and Relevance With the use of linked national data and validated computable phenotypes, no evidence was found of a benefit from ICP Monitoring on functional survival of children with severe TBI. Intracranial Pressure Monitoring is a widely but inconsistently used technology with incompletely demonstrated effectiveness. A large prospective cohort study or randomized trial is needed.

Joachim Oertel - One of the best experts on this subject based on the ideXlab platform.

  • telemetric Intracranial Pressure Monitoring with the raumedic neurovent p tel
    World Neurosurgery, 2016
    Co-Authors: Sebastian Antes, Christoph A Tschan, Michael Heckelmann, David Breuskin, Joachim Oertel
    Abstract:

    Background Devices enabling long-term Intracranial Pressure Monitoring have been demanded for some time. The first solutions using telemetry were proposed in 1967. Since then, many other wireless systems have followed but some technical restrictions have led to unacceptable measurement uncertainties. In 2009, a completely revised telemetric Pressure device called Neurovent P-tel was introduced to the market. This report reviews technical aspects, handling, possibilities of data analysis, and the efficiency of the probe in clinical routine. Methods The telemetric device consists of 3 main parts: the passive implant, the active antenna, and the storage monitor. The implant with its parenchymal Pressure transducer is inserted via a frontal burr hole. Pressure values can be registered with a frequency of 1 Hz or 5 Hz. Telemetrically gathered data can be viewed on the storage monitor or saved on a computer for detailed analyses. A total of 247 patients with suspected ( n  = 123) or known ( n  = 124) Intracranial Pressure disorders underwent insertion of the telemetric Pressure probe. Results A detailed analysis of the long-term Intracranial Pressure profile including mean values, maximum and negative peaks, pathologic slow waves, and pulse Pressure amplitudes is feasible using the detection rate of 5 Hz. This enables the verification of suspected diagnoses as normal-Pressure hydrocephalus, benign Intracranial hypertension, shunt malfunction, or shunt overdrainage. Long-term application also facilitates postoperative surveillance and supports valve adjustments of shunt-treated patients. Conclusions The presented telemetric measurement system is a valuable and effective diagnostic tool in selected cases.

Liangfu Zhou - One of the best experts on this subject based on the ideXlab platform.