Detection of early renal transplant rejection by minimally-invasive monitoring of impedance variability

Parsonnet, Victor; Marak, Mohamed J.; Panken, Eric; Zucker, Mark; Villanueva, Alexander; Kucher, T.; Driller, J.; Tuder, Gabriel; Olesnicky, Ludmilla; Combs, William

doi:10.1016/j.bios.2006.10.022

Cited by 4 publications

(1 citation statement)

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“…The electrical bioimpedance technique has been revealed as a valuable tool in the diagnosis of multiple diseases or tissular conditions, e.g. predicting the hypovolemia (Allison et al 2005, Cai et al 2002, detecting the rejection of some transplanted organs (Parsonnet et al 2007), Harms et al 2000, Harms et al 2001 or in the detection of tissular bubbles in divers (Jossinet et al 1981). In most applications the bioimpedance monitor should be as small as possible to minimize the effect of its presence on the host (Bogónez et al 2006).…”

Section: Introductionmentioning

confidence: 99%

An implantable bioimpedance monitor using 2.45 GHz band for telemetry

et al. 2012

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This paper describes a multi-frequency single-channel electrical implantable bioimpedance monitor (35 mm × 35 mm × 10 mm, weight 52 g) powered by a NiMH battery. By using the tetrapolar method and injecting 10 µA(peak), the monitor is capable of measuring at 14 different frequencies, from 100 Hz to 200 kHz. It contains a ZigBee transceiver to monitor the measurements performed, and has an embedded memory for backing up the data. RC networks and in-situ heart excised tissues were used to test the system. When measuring a full spectrum every 5 min, 35 days of autonomy are possible due to the low power consumption of the monitor. Temperature drift was estimated by short-term and long-term measurements. Temperature cycling was used to measure modulus and phase angle stability. The result was a very low effect on a modulus decrease of 2.34 Ω, with respect to an impedance of 322 Ω, at 100 Hz and a phase angle increase of 1.1°, at 200 kHz. In addition, measurement errors were bigger at low frequencies because of the high impedance of the electrodes used, which was higher than 10 kΩ at frequencies below 1 kHz.

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