The use of bioimpedance in the detection/screening of tongue cancer

Electric Bioimpedance Sensing for the Detection of Head and Neck Squamous Cell Carcinoma

The early detection of head and neck squamous cell carcinoma (HNSCC) is essential to improve patient prognosis and enable organ and function preservation treatments. The objective of this study is to assess the feasibility of using electrical bioimpedance (EBI) sensing technology to detect HNSCC tissue. A prospective study was carried out analyzing tissue from 46 patients undergoing surgery for HNSCC. The goal was the correct identification of pathologic tissue using a novel needle-based EBI sensing device and AI-based classifiers. Considering the data from the overall patient cohort, the system achieved accuracies between 0.67 and 0.93 when tested on tissues from the mucosa, skin, muscle, lymph node, and cartilage. Furthermore, when considering a patient-specific setting, the accuracy range increased to values between 0.82 and 0.95. This indicates that more reliable results may be achieved when considering a tissue-specific and patient-specific tissue assessment approach. Overall, this study shows that EBI sensing may be a reliable technology to distinguish pathologic from healthy tissue in the head and neck region. This observation supports the continuation of this research on the clinical use of EBI-based devices for early detection and margin assessment of HNSCC.

Bioimpedance: A Tool for Screening Oral Cancer - A Systematic Review

Objective

The successful management of cancer depends on proper screening and treatment methods. Bioimpedance spectroscopy (BIS) is an established technique in detecting breast cancer, cervical cancer, and prostate cancer. This systematic review sought to investigate the current evidence regarding the clinical application of bioimpedance in the detection of oral squamous cell carcinoma and oral potentially malignant disorders.

Study Design

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed to perform this review. Electronic databases such as PubMed, MEDLINE, Embase, EBSCOhost, and Google Scholar were searched till March 2022. Articles published in the English medical literature on human participants report on the application of BIS in the screening of precancerous and cancerous lesions. The primary endpoint was defined as the ability to differentiate between normal and cancerous tissue.

Results

A total of 6754 articles were identified; of which 481 were eligible for inclusion. Only five articles met the eligibility criteria and were included in the study. Qualitative analysis for each study was done to assess the data provided. All the studies demonstrated a significant divergence in BIS metrics between cancerous and normal tissue at 20 Hz and 50 KHz.

Conclusion

Bioimpedance appears to be a promising novel tool for the detection of various malignancies which can be used in community screening due to its noninvasiveness and portability.

Bioimpedance-Measurement-Based Non-Invasive Method for In Ovo Chicken Egg Sexing

Day-old male chick culling is one of the world's most inhumane problems in the poultry industry. Every year, seven billion male chicks are slaughtered in laying-hen hatcheries due to their higher feed exchange rate, lower management than female chicks, and higher production costs. This study describes a novel non-invasive method for determining the gender of chicken eggs. During the incubation period of fourteen days, four electrodes were attached to each egg for data collection. On the last day of incubation, a standard polymerase chain reaction (PCR)-based chicken gender determination protocol was applied to the eggs to obtain the gender information. A relationship was built between the collected data and the egg's gender, and it was discovered to have a reliable connection, indicating that the chicken egg gender can be determined by measuring the impedance data of the eggs on day 9 of incubation with the four electrodes set and using the self-normalization technique. This is a groundbreaking discovery, demonstrating that impedance spectroscopy can be used to sex chicken eggs before they hatch, relieving the poultry industry of such an ethical burden.

Bioelectrical Impedance Spectroscopy for Monitoring Mammalian Cells and Tissues under Different Frequency Domains: A Review

Bioelectrical impedance analysis and bioelectrical impedance spectroscopy (BIA/BIS) of tissues reveal important information on molecular composition and physical structure that is useful in diagnostics and prognostics. The heterogeneity in structural elements of cells, tissues, organs, and the whole human body, the variability in molecular composition arising from the dynamics of biochemical reactions, and the contributions of inherently electroresponsive components, such as ions, proteins, and polarized membranes, have rendered bioimpedance challenging to interpret but also a powerful evaluation and monitoring technique in biomedicine. BIA/BIS has thus become the basis for a wide range of diagnostic and monitoring systems such as plethysmography and tomography. The use of BIA/BIS arises from (i) being a noninvasive and safe measurement modality, (ii) its ease of miniaturization, and (iii) multiple technological formats for its biomedical implementation. Considering the dependency of the absolute and relative values of impedance on frequency, and the uniqueness of the origins of the α-, β-, δ-, and γ-dispersions, this targeted review discusses biological events and underlying principles that are employed to analyze the impedance data based on the frequency range. The emergence of BIA/BIS in wearable devices and its relevance to the Internet of Medical Things (IoMT) are introduced and discussed.

Impact of Age and Sex on Electrical Impedance Values in Healthy Oral Mucosa

Background: Electrical impedance (EI) is a property of all living tissues and represents the resistance to the electric current flow through a living tissue. EI depends on the structure and chemical composition of the tissue. The aim of this study was to determine the influence of age, sex, and electrode pressure on the EI values of healthy oral mucosa. The study involved 101 participants with healthy oral mucosa who were divided into three age groups. EI was measured in seven anatomical regions. Results: Significant differences between different age groups were found. Younger participants (20–40 years) had significantly higher EI values than the older participants (60+). Significantly higher EI values were found in women at all localisations at all measured frequencies, except on the hard palate. EI values measured with higher sub-pressure were significantly lower than values measured with lower sub-pressure at all frequencies and localisations, except the tongue dorsum, tongue border, and sublingual mucosa. Conclusions: This study found that EI values in healthy oral mucosa depend on age and sex and may also depend on the pressure of the measuring device. These factors should be kept in mind when EI is used as a diagnostic method for different oral lesions.

Electrical impedance tomography: a potential tool for intraoperative imaging of the tongue base

The presence of a tumor in the tongue is a pathology that requires surgical intervention from a certain stage. This type of surgery is difficult to perform because of the limited space available around the base of the tongue for the insertion of surgical tools. During the procedure, the surgeon has to stretch and then fix the tongue firmly in order to optimize the available space and prevent tissue movement. As a result, the preoperative images of the inside of the tongue no longer give a reliable indication of the position and shape of the cancerous tissue due to the deformation of the overall tissue in the area. Thus, new images are needed during the operation, but are very difficult to obtain using conventional techniques due to the presence of surgical tools. Electrical Impedance Tomography (EIT) is an imaging technique that maps the resistivity or difference of resistivity of biological tissues from electrical signals. The small size of the electrodes makes it a potentially interesting tool to obtain intraoperative images of the inside of the tongue. In this paper, the possibility of using EIT for this purpose is investigated. A detection method is proposed, including an original configuration of the electrodes, consistent with the anatomical specificities of the tongue. The proposed method is studied in simulation and then a proof of concept is obtained experimentally on a 3D printed test tank filled with saline solution and plant fibres.

Tensor electrical impedance myography identifies clinically relevant features in amyotrophic lateral sclerosis

Objective.Electrical impedance myography (EIM) shows promise as an effective biomarker in amyotrophic lateral sclerosis (ALS). EIM applies multiple input frequencies to characterise muscle properties, often via multiple electrode configurations. Herein, we assess if non-negative tensor factorisation (NTF) can provide a framework for identifying clinically relevant features within a high dimensional EIM dataset.Approach.EIM data were recorded from the tongue of healthy and ALS diseased individuals. Resistivity and reactivity measurements were made for 14 frequencies, in three electrode configurations. This gives 84 (2 × 14 × 3) distinct data points per participant. NTF was applied to the dataset for dimensionality reduction, termed tensor EIM. Significance tests, symptom correlation and classification approaches were explored to compare NTF to using all raw data and feature selection.Main Results.Tensor EIM provides highly significant differentiation between healthy and ALS patients (p< 0.001, AUROC = 0.78). Similarly tensor EIM differentiates between mild and severe disease states (p< 0.001, AUROC = 0.75) and significantly correlates with symptoms (ρ= 0.7,p< 0.001). A trend of centre frequency shifting to the right was identified in diseased spectra, which is in line with the electrical changes expected following muscle atrophy.Significance.Tensor EIM provides clinically relevant metrics for identifying ALS-related muscle disease. This procedure has the advantage of using the whole spectral dataset, with reduced risk of overfitting. The process identifies spectral shapes specific to disease allowing for a deeper clinical interpretation.

Virtual Biopsy by Electrical Impedance Spectroscopy in Barrett's Carcinoma

Purpose

Early detection of adenocarcinomas in the esophagus is crucial for achieving curative endoscopic therapy. Targeted biopsies of suspicious lesions, as well as four-quadrant biopsies, represent the current diagnostic standard. However, this procedure is time-consuming, cost-intensive, and examiner-dependent. The aim of this study was to test whether impedance spectroscopy is capable of distinguishing between healthy, premalignant, and malignant lesions. An ex vivo measurement method was developed to examine esophageal lesions using impedance spectroscopy immediately after endoscopic resection.

Methods

After endoscopic resection of suspicious lesions in the esophagus, impedance measurements were performed on resected cork-covered tissue using a measuring head that was developed, with eight gold electrodes, over 10 different measurement settings and with frequencies from 100 Hz to 1 MHz.

Results

A total of 105 measurements were performed in 60 patients. A dataset of 400 per investigation and a total of more than 42,000 impedance measurements were therefore collected. Electrical impedance spectroscopy (EIS) was able to detect dysplastic esophageal mucosa with a sensitivity of 81% in Barrett’s esophagus.

Conclusion

In summary, EIS was able to distinguish different tissue characteristics in the different esophageal tissues. EIS thus holds potential for further development of targeted biopsies during surveillance endoscopy.

Trial Registration

NCT04046601

Adaptive Extreme Edge Computing for Wearable Devices

Wearable devices are a fast-growing technology with impact on personal healthcare for both society and economy. Due to the widespread of sensors in pervasive and distributed networks, power consumption, processing speed, and system adaptation are vital in future smart wearable devices. The visioning and forecasting of how to bring computation to the edge in smart sensors have already begun, with an aspiration to provide adaptive extreme edge computing. Here, we provide a holistic view of hardware and theoretical solutions toward smart wearable devices that can provide guidance to research in this pervasive computing era. We propose various solutions for biologically plausible models for continual learning in neuromorphic computing technologies for wearable sensors. To envision this concept, we provide a systematic outline in which prospective low power and low latency scenarios of wearable sensors in neuromorphic platforms are expected. We successively describe vital potential landscapes of neuromorphic processors exploiting complementary metal-oxide semiconductors (CMOS) and emerging memory technologies (e.g., memristive devices). Furthermore, we evaluate the requirements for edge computing within wearable devices in terms of footprint, power consumption, latency, and data size. We additionally investigate the challenges beyond neuromorphic computing hardware, algorithms and devices that could impede enhancement of adaptive edge computing in smart wearable devices.

Noninvasive and real-time in vivo characterization of Inflammation skin. A feasibility of animal study

BACKGROUND

Inflammatory skin diseases were the most common problem in dermatology. This study aimed to develop a circuit by using a simple method for noninvasive, objective, and real-time skin inflammation screening.

MATERIALS AND METHODS

Sprague-Dawley rats were used in this study. The rats were chemically induced to suffer from skin inflammation at the back of their left-hand side while the right-hand side of their back remained untreated serving as a control. Impedance (Z) spectrum of the rat's skin was recorded.

RESULTS

Two characteristic frequencies (4.5 and 48.3 kHz) were found. At the two frequencies, the impedance of inflammatory skin tissue (Z_IST ) was found to be significantly (P < .05) smaller than that of normal healthy skin tissue (Z_NHST ). Moreover, the ratio of the impedance measured at 4.5 kHz (Z_f = 4 ._5 kHz ) to the impedance measured at 48.3 kHz (Z_{f = 48.3 kHz} ), that is, Z_{f = 4.5 kHz} /Z_{f = 48.3 kHz} , was capable of skin inflammation screening. It was observed that the inflammatory skin tissue (IST) had the smaller value of Z_f = 4 ._5 kHz /Z_{f = 48.3 kHz} (value < 8.5) and normal healthy skin tissue (NHST) had the higher value of Z_f = 4 ._5 kHz /Z_{f = 48.3 kHz} (value ≈ 10) which almost remained constant.

CONCLUSION

A circuit was developed which was used for measuring the skin impedance accurately at the two characteristic frequencies for skin inflammation screening.

The clinical application of electrical impedance technology in the detection of malignant neoplasms: a systematic review

BACKGROUND

Electrical impedance technology has been well established for the last 20 years. Recently research has begun to emerge into its potential uses in the detection and diagnosis of pre-malignant and malignant conditions. The aim of this study was to systematically review the clinical application of electrical impedance technology in the detection of malignant neoplasms.

METHODS

A search of Embase Classic, Embase and Medline databases was conducted from 1980 to 22/02/2018 to identify studies reporting on the use of bioimpedance technology in the detection of pre-malignant and malignant conditions. The ability to distinguish between tissue types was defined as the primary endpoint, and other points of interest were also reported.

RESULTS

731 articles were identified, of which 51 reported sufficient data for analysis. These studies covered 16 different cancer subtypes in a total of 7035 patients. As the studies took various formats, a qualitative analysis of each cancer subtype's data was undertaken. All the studies were able to show differences in electrical impedance and/or related metrics between malignant and normal tissue.

CONCLUSIONS

Electrical impedance technology provides a novel method for the detection of malignant tissue, with large studies of cervical, prostate, skin and breast cancers showing encouraging results. Whilst these studies provide promising insights into the potential of this technology as an adjunct in screening, diagnosis and intra-operative margin assessment, customised development as well as multi-centre clinical trials need to be conducted before it can be reliably employed in the clinical detection of malignant tissue.

Design and Development of a Low-Cost Arduino-Based Electrical BioImpedance Spectrometer

Background

Bioimpedance spectroscopy (BIS) is a device used to measure electrical impedance at frequencies from 0 Hz to 1 MHz. Many clinical diagnosis and fundamental researches, especially in the field of physiology and pathology, rely on this device. The device can be used to estimate human body composition, through the information of total body water, extracellular fluid and intracellular fluid, fat-free mass, and fat mass from its impedance. BIS analysis can provide physiological statuses such as ischemia, pulmonary edema, skin cancer, and intramuscular tumors. BIS is expected to be used even more widely, both for hospital or home-based use, particularly because BIS handy, compact, inexpensive, and less power-consuming with adequately accurate real-time. In previous research, the BIS design was based on the magnitude-ratio and phase-difference detection using the AD8302 gain-phase detector method which resulted in an operating range between 20 kHz and 1 MHz. However, the impedance was obtained from the logarithmic ratio magnitude which caused the device to have limited accuracy at frequencies <20 kHz.

Methods

In this research, we conduct design and development of a low-cost arduino-based electrical bioimpedance spectrometer.

Results

The low-cost bioimpedance spectrometry was successfully developed using AD9850 as the programmable function generator, OPA2134 as the OpAm of voltage-controlled current source, AD620A as the instrument amplifier and AD536A as the alternating current to direct current converter which could work accurately from 0 Hz to 100 kHz.

Conclusion

The multi-frequency bioimpedance device developed in this research has the capability to safely measure the impedance of the human body due to its relatively stable electric current, which is equal to (0.370 ± 0.003) mA with frequencies ranging from 5 to 200 kHz and has an accuracy of over 90% in the frequency range of 10 Hz to 100 kHz.

Identification of Pulmonary Nodules by Sweeping the Surface of the Lung with an Electrical Bioimpedance Probe: A Feasibility Study

Purpose: Identifying and localizing the invisible and nonpalpable pulmonary nodules are among the main challenges surgeons face during open and thoracoscopic surgeries. This in vitro study explores the feasibility of utilizing a simple and safe electrical bioimpedance probe in locating the pulmonary nodules by sweeping the surface of the lung tissue. Methods: A probe was designed with four spherical electrodes that were used for recording the bioimpedance spectrum of the lung tissue in a frequency range of 50 kHz to 5 MHz. In each of the 10 resected surgical specimens, the bioimpedance of normal lung tissue as well as the tumoral lung tissue were recorded and compared with each other. Results: By drawing the Nyquist curves, it was determined that the amplitude of the electrical impedance measured by moving the probe from the healthy point to the region of the pulmonary nodule decreases and the frequency characteristics of the bioimpedance spectrum increases. Conclusion: This method could be potentially beneficial in the localization of invisible and even nonpalpable in-depth pulmonary nodules in thoracic surgeries.

Bioimpedancemetry for the assessment of periodontal tissue inflammation: a numerical feasibility study

In dentistry possible inflammatory episodes of oral cavity can be very frequent (periodontitis, mucositis, peri-implantitis) and they can have serious consequences. Indeed, peri-implantitis is still the principal cause of implant failure. Impedance values of biological tissues are related to the physiological/pathological state of the tissue itself. In fact, an inflamed site exhibits an impedance value lower than that of the corresponding healthy tissue. Based on these observations, the aim of this work is to determine if impedancemetric measurements are able to provide information about the inflammatory state of tissues. A numerical 3D model has been realized to simulate the measurement conditions present in the event of inflammation around a dental implant. The aim is to understand if it is possible to determine the presence of an inflamed tissue and to locate its site, so that the treatment could be specifically focused in that specific area. A simplified geometry reproducing the implant has been realized in order to validate the numerical model by means of experimental measurements. The obtained results are satisfactorily accurate, so the model can be considered reliable. Therefore, multiple simulations have been run on the original model to carry out a parametric study in terms of different conductivity values, different volumes of inflamed tissues and different measurement frequencies. The advantages and limits of such a method have been shown to properly define the main constraints for the system design.

Mapping Electrical Impedance Spectra of the Healthy Oral Mucosa: a Pilot Study

OBJECTIVE

Electrical impedance is the resistance to the electric current flow through a tissue and depends on the tissue's structure and chemical composition. The aim of this study was to map electrical impedance spectra for each region of the healthy oral mucosa.

MATERIALS AND METHODS

Electrical impedance was measured in 30 participants with healthy oral mucosa. Measurements were performed in 14 points on the right and the left side of the oral cavity, and repeated after 7 and 14 days respectively.

RESULTS

The lowest values were measured on the tongue dorsum and the highest values were measured on the hard palate. No significant differences were found between the right and the left side. Significantly higher values were found in females on the upper labial mucosa, tongue dorsum and the ventral tongue. Significant difference between smokers and non-smokers on the lower labial mucosa and floor of the mouth was found. Electrical impedance was negatively correlated with salivary flow on the upper labial mucosa, hard palate, tongue dorsum and sublingual mucosa. Higher variability of measurements was found at low frequencies.

CONCLUSIONS

Electrical impedance mostly depends on the degree of mucosal keratinization. Demographic and clinical factors probably affect its values. Further studies with bigger number of participants are required.

Use of electrical impedance spectroscopy to detect malignant and potentially malignant oral lesions

The electrical properties of tissues depend on their architecture and cellular composition. We have previously shown that changes in electrical impedance can be used to differentiate between different degrees of cervical dysplasia and cancer of the cervix. In this proof-of-concept study, we aimed to determine whether electrical impedance spectroscopy (EIS) could distinguish between normal oral mucosa; benign, potentially malignant lesions (PML); and oral cancer. EIS data were collected from oral cancer (n=10), PML (n=27), and benign (n=10) lesions. EIS from lesions was compared with the EIS reading from the normal mucosa on the contralateral side of the mouth or with reference spectra from mucosal sites of control subjects (n=51). Healthy controls displayed significant differences in the EIS obtained from different oral sites. In addition, there were significant differences in the EIS of cancer and high-risk PML versus low-risk PML and controls. There was no significant difference between benign lesions and normal controls. Study subjects also deemed the EIS procedure considerably less painful and more convenient than the scalpel biopsy procedure. EIS shows promise at distinguishing among malignant, PML, and normal oral mucosa and has the potential to be developed into a clinical diagnostic tool.

Diagnosing early Barrett's neoplasia and oesophageal squamous cell neoplasia by bioimpedance spectroscopy in human tissue

BACKGROUND

Detection of early oesophageal cancer in surrounding normal tissue can be challenging, but detection is essential to determine the subsequent treatment. Dysplastic tissue can be detected by using electrical impedance spectroscopy (EIS).

OBJECTIVE

The aim of the present study was to evaluate the feasibility and value of EIS in the diagnosis of oesophageal neoplasia.

METHODS

This prospective ex-vivo study included 23 patients with early oesophageal cancer (17 with Barrett's cancer and six with early squamous cell cancer). Immediately after endoscopic resection, the electrical properties of the resected specimens were investigated using a pencil probe (5 mm in diameter, frequency range from 100 Hz to 1 MHz). Punch biopsies were taken from the measured site in order to compare the results of EIS with histology.

RESULTS

EIS was able to detect dysplastic oesophageal mucosa with a high rate of accuracy (82% in Barrett's oesophagus and 100% in squamous oesophagus) A total of 54 different sites in 26 tumours were evaluated.

CONCLUSIONS

EIS was able to differentiate reliably between non-neoplastic and neoplastic oesophageal mucosa. Using EIS, it might be possible to use it for targeted biopsies and to avoid unnecessary biopsies during cancer surveillance in future.

Design of a complex bioimpedance spectrometer using DFT and undersampling for neural networks diagnostics

Electrical impedance spectroscopy offers many applications in the medical field due the fast response, non-invasiveness and low cost. One promising area is the use of this method for diagnostics. This paper describes the design and experimental evaluation of a multifrequencial complex bioimpedance analyzer. Impedance amplitude and phase were calculated using Discrete Fourier Transform (DFT) and high frequency signals were measured with undersampling. The prototype was able to measure values from 1 Ω to 50 kΩ (frequency range from 50 Hz to 500 kHz). The accuracy of the technique was compared with a commercial equipment. The analysis of passive components resulted in a mean error of 2.9% for the magnitude and 0.69 degrees for the phase. Besides, an initial study for head and neck cancer detection through neural networks is shown. One used bioimpedance values as well as gender, age and body mass index as inputs. The network used 120 training and 40 validation data and was able to simulate 77.5% of the two types of diagnostic correctly.