Bioimpedance techniques

Bioimpedance techniques are interesting candidates for diagnosing disorders in the urinary system. There are many possible applications, ranging from measurements of uterine tone and contractility to assessment of prelabor ripening and detection of cervical cancer. Some examples are as follows. 

Complications related to pulmonary artery catheter insertion, maintenance, and removal include damage to vessels and organs during insertion, arrhythmias, infections, and thromboembolic damage. To avoid the complications associated with pulmonary artery catheterization, other less invasive tools were developed to obtain similar information. For example, cardiac output determinations have been made by Doppler, bioimpedance, dye, and ionic dilution techniques, although such measurements would not provide other data that are obtained routinely with pulmonary artery catheters (e.g., left-sided heart-filling pressure). Additionally, advances in... 

Although not evident from the title, rheoencephalography is a plethysmographic technique based on bioimpedance and with focus on cerebral blood flow (Bodo et al. 2004 Grimnes and Martinsen 2008 Bodo 2010). 

Bioimmittance is measured in vivo or in vitro. The tissue may be kept alive and perfused under ex vivo conditions. Bioimmittance can be measured with two-, three- or four-electrode systems. With four electrodes, one electrode pair is current carrying and the other pair picks up the corresponding potential difference somewhere else in the tissue. If the measured voltage is divided by the applied current, the transfer impedance is calculated. If no voltage is measured, the transfer impedance is zero. This is equivalent to the bioelectricity case in which a signal from the source, such as the heart, is transferred to the skin surface electrodes. Zero transfer impedance does not mean the tissue conducts well, only that no signal transfer occurs. With the bioimpedance two-electrode technique, the transfer factor is eliminated because current application and signal pickup occur at the same site, which means that measured impedance reflects tissue electrical properties more directly. 

Bera T. K., Biswas S. K., Rajan K., and Nagaraju J., Improving image quality in electrical impedance tomography (EIT) using projection error propagation-based regularization (PEPR) technique A simulation study,. Elec. Bioimpedance, vol. 2, pp. 2-12, doi 10.5617/jeb.l58, 2011. 

Although the technique is simple, hardware and software development for biological impedance measuring is a hard work. Many electrical bioimpedance (BIA) applications have been used dedicated circuits as, for example, the... 

BIA is a simple and low-cost technique for body composition diagnosis. The correct use of R and Xc with the predictive equations is important for calculating the body components, such as FFM and TBW. However, the estimation of the body composition by BIA depends on the collected data from DXA, for example. Although the predictive equations can change according to target population, there are many works in the literature that show equations with good correlation between bioimpedance and standardized methods [14]. 

Bioimpedance is a non-invasive, safe and relatively inexpensive technique to assess body composition of both healthy and illness patients. The body impedance analyzer developed in this work was conducted according to the requirements of healthcare applications, such as portability and low cost. These characteristics are considered very important for large-scale use, benefiting the National Health System (NHS) and homecare users. It can be concluded that the developed system can be used for body composition assessment over a wide aging range. 

Our results suggest that bioimpedance method can be useful in testing or controlling the inotropic effects of the injected substances if the more trnstful but expensive and sophisticated techniques cannot be employed. The bioim-pe ce method can be successfnlly applied for toxicological... 

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