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Fully simultaneous polysomnography (PSG) and electrical impedance tomography (EIT) incorporated with partially synchronized computed tomography (CT) scan were used to investigate the performance of EIT on the monitoring of obstructive sleep apnea (OSA) occurring on the upper airway. The opening and closing of the upper airway will lead to different conductivity distribution which can be visualized through the EIT images. In this study, two rings of 16 electrodes were attached on the upper and lower transverse planes of airway, and the behavior of airway is extracted through the independent component analysis (ICA) algorithm with the reference of airway flow obtained through PSG due to the efficient synchronization. Refereed to the anatomical structures from CT scans, the performance of the EIT in monitoring the sleep disorder will be validated and presented through the reconstructed EIT images on both upper-layer and lower-layer. [ABSTRACT FROM AUTHOR]

Cervical intraepithelial neoplasia (CIN) refers to the precancerous and abnormal changes of the surface cells of the cervix, and the variants of electrical properties of CIN are associated with the premalignant stages of cervical intraepithelial neoplasia. This provides the fundamental knowledge and foundation of the feasibility of electrical impedance spectroscopy in the screening and diagnosis of CIN. In this study, an electrical impedance spectroscopy-based multi-electrode probe was brought forward to assist the screening of cervical intraepithelial neoplasia which is cost-effective, high sensitivity, non-invasive, and real-time. The multi-electrode probe was designed to have 2 concentric rings of 8 electrodes (16 in total) and enable the protocol flexibility of current injection and voltage measurements. The conductivity will be recovered using the predesigned current-voltage protocol by the embedded concentration algorithm, and the induced frequency spectrum will be presented to show the frequency-dependent phenomenon of cervical cells when excited at various frequencies. The electrical parameters R, S were extracted from frequency spectra of 141 subjects based on Cole model, and receiver operator characteristic (ROC) curve generated by various variables was analyzed to validate the performance. [ABSTRACT FROM AUTHOR]

Cervical intraepithelial neoplasia (CIN) is the precancerous stage of cervical cancer. Accurate and straightforward CIN screening and subsequent treatment and management of early detected CIN highly reduce the occurrence of cervical cancer, which is the 4th most common cancer among women. Bioimpedance spectroscopy (BIS) has been proposed as a CIN screening method since it is varied in the electrical characteristics depending on the progression of CIN. Before applying the BIS system, including a multi-electrode probe to in-vivo tissue, we wanted to evaluate it on the in-vitro cervical tissues obtained from loop electrosurgical excision procedure (LEEP). Unfortunately, the measurement accuracy of in-vitro cervical tissues is highly determined by the size, the presence or absence of mucus, and the condition of the surface of tissue samples. This study presents a brief investigation into the technical issues during the impedance measurements for tissue samples. A few methods, including model fitting, gain adjustment, and saline calibration, have been introduced to check measurement quality using our newly proposed multi-electrode probe. [ABSTRACT FROM AUTHOR]

The overnight polysomnography (PSG) is the gold standard to diagnose obstructive sleep apnea (OSA) using the apnea and hypopnea index (AHI), which is the average number of apnea and hypopnea per hour during sleep. Unfortunately, the single metric of AHI is not sufficient to quantify the severity of sleep disorder when patients with similar AHI have a significantly distinct amount of tidal volume. In this study, electrical impedance tomography (EIT) has been utilized to quantitatively evaluate the severity of OSA, which takes account of the tidal volume reduction and duration for sleep-related breathing disorders. We could present that the additional information obtained from EIT during overnight PSG describes a more accurate estimation of the OSA severity. [ABSTRACT FROM AUTHOR]

In the previous studies, single-layer electrical impedance tomography (EIT) combined with polysomnography (PSG) has been proposed to detect the upper airway narrowing or closure during sleep noninvasively. Unfortunately, by generating the cross-sectional EIT image at one level, single-layer EIT fails to identify the collapse site in terms of the retropalatal and retroglossal levels of the upper airway, which is of great importance in the clinical practice. In this study, double-layer EIT has been proposed to image the obstruction site of patients with obstructive sleep apnea (OSA). It could provide beneficial supplementary information to facilitate the personalized surgical procedure for OSA. [ABSTRACT FROM AUTHOR]

The screening of cervical intraepithelial neoplasia (CIN) aims to provide a chance for early detection and treatment of the pathological behavior of cervical tissues before it progresses to cervical cancer. In this study, a bioimpedance spectroscopy-based multi-electrode probe has been developed to measure the complex impedance of the cervix and adopted for the screening of CIN. In addition, the classical Cole-Cole model has been adopted to extract electrical parameters and thereby generate geometrical parameters with respect to cervical tissues, which were afterward exploited for CIN identification. Results show that the proposed features demonstrate a significant difference among different groups of CIN and thus provide a real-time, non-invasive, and cost-effective technique for screening CIN with high sensitivity and specificity. [ABSTRACT FROM AUTHOR]

Many patients rapidly develop hypotension during hemodialysis, causing great difficulties in continuing clinical treatments. When this intradialytic hypotension happens with some symptoms, clinicians prescribe therapeutic interventions like decreasing ultrafiltration rate (UF-) and injecting normal saline (S+) based on personal clinical experience. However, these kinds of interventions have a different response for each patient and could reduce the effectiveness of dialysis. This study attempted non-invasive real-time monitoring of hemodynamic parameters using electrical impedance tomography (EIT). We investigated the influence of prescribed interventions on hemodynamic changes during hemodialysis. Significant differences were observed in the EIT data before and after each intervention. [ABSTRACT FROM AUTHOR]

Electrical impedance tomography (EIT) could be used to monitor cardiopulmonary function for patients undergoing hemodialysis (HD), non-invasively. Cardiac-related volume signals (CVS) extracted from EIT measurements have limited performance in monitoring hemodynamic changes during HD because of their small size and high sensitivity to motion noise. These motion artifacts (MA) may cause misinterpretation of hemodynamic status monitored by EIT. In this study, a MA detection algorithm has been proposed for hemodynamic monitoring during HD using an electrocardiogram (ECG) signal acquired simultaneously. For the sake of performance evaluation, the heart rate (HR) extracted from CVS before and after MA is compared with that by ECG. The proposed method demonstrated a good performance to detect MA (Sensitivity = 0.74, Specificity = 0.9) and facilitates the correction of MA in the CVS signal. [ABSTRACT FROM AUTHOR]