Article

Electrical impedance scanning: A new approach to skin cancer diagnosis

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Abstract

Skin cancer diagnosis depends, to a great extent, on visual inspection and histopathological examination of excised tissues. The aim of this study is to evaluate the ability of electrical impedance scanning to differentiate between benign and malignant skin lesions. A preclinical study was conducted on 40 nude mice injected subcutaneously with a human melanoma strain. Impedance measurements were recorded every week to correlate electrical changes with tumor growth and histological findings. A clinical study was also performed on 178 human suspicious skin lesions before excision. The impedance measurements were correlated to the histopathological results. Normalized conductivity and capacitance, recorded on growing skin tumors in nude mice, were shown to change relative to lesion size. Necrosis, present in most of the larger lesions, was associated with a decrease in the electrical conductivity. Similar electrical parameters were used to classify human melanoma lesions with 92% sensitivity and 67% specificity. In addition, four out of five BCC lesions were correctly diagnosed. Moreover, dysplastic lesions were diagnosed with 91% sensitivity and 59% specificity. For comparison, physicians diagnosed melanoma lesions with 75% sensitivity and 87% specificity and dysplastic lesions with 46% sensitivity and 80% specificity. The animal study showed that electrical impedance measurements reflect morphological changes related to the growth of a cancerous skin lesion. These findings are in agreement with a preliminary clinical study. Electrical Impedance Scanning can therefore be considered as an objective and non-invasive tool for differentiation between benign and malignant skin lesions.

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... Electrode material for impedance devices usually consists of either gold or silversilver chloride (Ag/AgCl) [28,34]. Gold is a good conductor and used frequently in microelectrode devices. ...
... The 2 kHz frequency was selected because of its expected position at the !-dispersion point for skin and its use by Glickman and Har-Shai [33,34]. The 10 kHz frequency was chosen for its use by Gabriel and Stante [18,36]. ...
... Thus, the reactance values included in the statistical analysis for both constructs at 10 kHz were reliable.With all resistances and the majority of reactances determined to be in an acceptable range for the ELVIS system, the impedance data was concluded to be reliable.Impedance consists of both resistance and reactance as per Equation 4.The average impedance of Epiderm TM constructs was less than that of Melanoma constructs. This relationship was in opposition to the data found in the literature, but consistent with Glenn Stante's findings[18,33,34]. Possible reasons for the disagreement with the literature most likely stemmed from the tissue samples themselves.Firstly, other student's in unrelated projects used the tissue samples previously. ...
Article
Melanoma skin cancer is the abnormal growth of the melanocytes – the pigmented cells located in the epidermis. The current gold standard diagnostic technique for determining whether a lesion is cancerous involves subjectively examining suspicious lesions and performing an invasive biopsy to confirm melanoma. This method may neglect some lesions or cause scarring from biopsies that turn out to be benign. Thus, impedance-based detection using a multi-electrode device was investigated as a noninvasive technique to diagnose melanoma skin cancer. The multi-electrode device was designed with 8 equally spaced Ag/AgCl electrodes surrounding one central electrode at a 5 mm radius. The electrodes were held in place by a vice-like mechanism using three circular Delrin sections. The electrodes were interfaced to an 8:1 multiplexer and National Instruments Educational Laboratory Virtual Instrumentation Suite (ELVIS) for measurement control and impedance analysis. The ELVIS system, multiplexer, and electrode device were validated for accuracy with various values of resistors and capacitors. Raw and cooked chicken thigh meat and skin were tested to evaluate the capabilities of the electrode device to discern different tissue types and tissue moisture contents by impedance measurements. EpidermTM and Melanoma tissue-engineered skin analogues, provided by MatTek Corporation, were tested to mimic the in situ disease state. The electrode device was found to produce reliable measurements for known electrical components with resistances between 10 ohms and 100 k-ohms and capacitances between 10 nF and 10 uF. The measurements from the chicken tissues and tissue-engineered skin constructs – excluding cooked chicken skin data – fell within the reliable range of the electrode device and were thus considered reliable as well. All analyses concluded that a statistical difference between the impedances of raw meat and raw skin, cooked meat and raw meat, and EpidermTM and Melanoma existed. Therefore, the hypothesis that a multi-electrode device could differentiate between melanoma and healthy skin tissues based on impedance measurements was satisfied.
... It is desirable to replace this subjective procedure with a non-invasive, reliable, simple, and objective technique with high accuracy, but at the time of writing there are no practical alternatives. Electrical impedance has been used to assess skin cancer with positive outcome and it has been proposed that electrical impedance could be used as a possible alternative to visual screening for skin cancer [52][53][54][55][56][57]. ...
... The ROC curve are remarkably useful tools in medical decision-making, and electrical impedance was used together with ROC e.g. in cervix cancer detection [91], in detection of malignancy areas in the bladder [92], and to describe the performance of separation of malignant and benign cutaneous lesions in [55,56]. ...
... 511 benign lesions is a significantly larger population than 16) than Dua et al. [52] and achieved similar accuracy, which confirms their results. In the report by Glickman et al. [55] only one frequency (2 kHz), without depth the discrimination, was used to separate melanoma and benign lesions, which might explain their somewhat lower accuracy. ...
Article
ABSTRACT This thesis describes the relation between ,skin cancer and electrical impedance. On the cellular level, electrical impedance measured at clinically relevant frequencies is affected by e.g. membrane ,structure and orientation, and composition of and relation between the intra- and extracellular environments, i.e. similar properties used by histopathologists todiagnose skin cancer. The aim is to detect skin cancer using the electrical impedance technique. The overall objective is to develop a complement,to visual skin cancer screening. Impedance was measured with a depth selective impedance spectrometer between 1 kHz and 1 MHz of various skin cancers and benign lesions including e.g. malignant melanoma, squamous and basal cell carcinoma, dysplastic nevi, actinic keratosis, and benign pigmented nevi. The lesions were subsequently excised and diagnosed by histopathology. Various pattern recognition tools were used to analyse the impedance data.
... Diagnostic methods based on EI measurement are used in different fields of medicine. EI spectroscopy, which is the most widely used method, has a long history (Fere and Tarhanov 1888.g), and has been mostly used for the assessment of skin lesions (3)(4)(5)(6). EI is also applied in the assessment of the severity of muscle ischaemia (2). Methods of EI tomography assist in the evaluation of ischemic heart disease and pulmonary edema (7,8). ...
... Lately, these methods have been increasingly used in the detection of tumors in different tissues. Thus, EI spectroscopy can be used to assess different tumor lesions on the skin, breast and female reproductive organs (3,4,10,11). The application of EI measurements has already been established in dentistry through the use of different apex locators for the root canal length de- ...
... Posljednjih godina ove se metode sve češće primjenjuju u detekciji tumorskih promjena u različitim tkivima. Tako se impedancijskom spektrografijom mogu procjenjivati različite tumorske tvorbe na koži, u dojci i na sluznici ženskih reproduktivnih organa (3,4,10,11). Bioimpedacijska mjerenja već su ustaljena u stomatološkoj praksi korištenjem različitih apeksnih lokatora za određi-www.ascro.hr ...
Article
Full-text available
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.
... Another major benefit of this technique is that it provides fundamentally different information than the above-mentioned techniques. Several early studies to distinguish skin cancer from normal skin noted demerits such as the requirement of complex algorithms, inapplicability in humans, and higher cost [Glickman et al., 2003;Hartinger et al., 2008;Mohr et al., 2013]. However, advancements made in this technique over time made it an ideal technique for the detection of early skin cancer [Sarac et al., 2020]. ...
... Furthermore, in the case of larger lesions, higher conductivity was noticed at the edges of lesions compared to the center, which is attributed to local degenerative necrosis at the center of lesions. A similar system in a clinical setting of 178 human skin lesions (113 benign, 48 dysplastic, and eight melanoma) noted a sensitivity of 92%, higher than the visual diagnosis [Glickman et al., 2003]. In another study conducted on 449 preoperative lesions, electrical impedance scanning detected smaller melanomas (<15 mm) and bigger melanomas (>15 mm) with a sensitivity of 100% and 81%, respectively. ...
Article
Skin cancer is among the fastest‐growing cancers with an excellent prognosis, if detected early. However, the current method of diagnosis by visual inspection has several disadvantages such as overlapping tumor characteristics, subjectivity, low sensitivity, and specificity. Hence, several adjunctive diagnostic techniques such as thermal imaging, optical imaging, ultrasonography, tape stripping methods, and electrical impedance imaging are employed along with visual inspection to improve the diagnosis. Electrical impedance‐based skin cancer detection depends upon the variations in electrical impedance characteristics of the transformed cells. The information provided by this technique is fundamentally different from other adjunctive techniques and thus has good prospects. Depending on the stage, type, and location of skin cancer, various impedance‐based devices have been developed. These devices when used as an adjunct to visual methods have increased the sensitivity and specificity of skin cancer detection up to 100% and 87%, respectively, thus demonstrating their potential to minimize unnecessary biopsies. In this review, the authors track the advancements and progress made in this technique for the detection of skin cancer, focusing mainly on the advantages and limitations in the clinical setting.
... There has been research into impedance spectroscopy of skin cells to detect melanoma cells. Previous research such as Glickman (2003) et al. showed that impedance spectroscopy was able to classify human melanoma lesions with 92% sensitivity and 67% specificity [15]. Stante (2009) ...
... There has been research into impedance spectroscopy of skin cells to detect melanoma cells. Previous research such as Glickman (2003) et al. showed that impedance spectroscopy was able to classify human melanoma lesions with 92% sensitivity and 67% specificity [15]. Stante (2009) ...
Article
MEASURING IMPEDANCE OF TISSUES USING A MICROFABRICATED MICROELECTRODE ARRAY By Ashwini Bhat This thesis looks at the possibility of using impedance spectroscopy for differentiating tissue, using a microelectrode array (MEA). The thesis first discusses the background and the motivation for this thesis. It covers the certain basic concepts of the human skin starting from the top epidermis layer all the way to the deep dermis layers of the skin. Then it discusses different types of skin cancer and how they occur, in humans. It also discusses various microfabrication techniques such as oxidation, wet etching, sputtering and photolithography for the creation of a MEA in order to test the tissue. The microfabricated MEA is then used to measure impedance across cooked and raw chicken at different frequencies in order to see if the two types of tissues can be differentiated using their respective impedances. The data shows that the MEA was not able to successfully differentiate the two types of the tissues. It does however list multiple improvements in the fabrication of the MEA and improvements that could be made to the testing procedures which could possible give greater difference in impedance between the two tissues
... Biological tissue has electrical properties, which relate to both its cell structure and frequency characteristics [1]. Electrical bioimpedance is applied to electrical impedance tomography (EIT) e.g. in lung respiration monitoring [2], and in electrical impedance spectroscopy (EIS) for characterization of tissue e.g. for skin cancer detection [3]. The current generator is an important building block of any electrical bioimpedance system. ...
Conference Paper
This paper describes the design of fully differential sine pulse-width-modulation (SPWM) wave current generator for bioimpedance measurement applications. The current generator has been designed in a 0.18-µm CMOS technology. Its analog front-end operates from ±1.65 V and has a current consumption of + + ( ×. ) where is the output current and is the operating frequency. It can provide outputs from to of SPWM current up to 98 kHz with a maximum voltage compliance of ±1.25 V. Using linear current feedback, the current generator has a designed transconductance of /. Feedback also enables cancellation of common mode signals and a high output impedance.
... It has also been applied to distinguish allergic and irritant contact dermatitis by evaluating the degree of irritation in human skin [13][14][15]. In addition, the electrical impedance values have been assessed to discriminate skin tumors, such as melanoma, dysplastic nevi, nodular basal cell carcinoma, superficial basal cell carcinoma, as well as benign and malignant skin lesions [16][17][18][19][20][21][22]. Clavus has a much thicker stratum corneum and a thinner epidermis than verruca. ...
Article
Full-text available
Similar clinical appearances prevent accurate diagnosis of two common skin diseases, clavus and verruca. In this study, electrical impedance is employed as a novel tool to generate a predictive model for differentiating these two diseases. We used 29 clavus and 28 verruca lesions. To obtain impedance parameters, a LCR-meter system was applied to measure capacitance (C), resistance (Re), impedance magnitude (Z), and phase angle (θ). These values were combined with lesion thickness (d) to characterize the tissue specimens. The results from clavus and verruca were then fitted to a univariate logistic regression model with the generalized estimating equations (GEE) method. In model generation, log ZSD and θSD were formulated as predictors by fitting a multiple logistic regression model with the same GEE method. The potential nonlinear effects of covariates were detected by fitting generalized additive models (GAM). Moreover, the model was validated by the goodness-of-fit (GOF) assessments. Significant mean differences of the index d, Re, Z, and θ are found between clavus and verruca (p<0.001). A final predictive model is established with Z and θ indices. The model fits the observed data quite well. In GOF evaluation, the area under the receiver operating characteristics (ROC) curve is 0.875 (>0.7), the adjusted generalized R2 is 0.512 (>0.3), and the p value of the Hosmer-Lemeshow GOF test is 0.350 (>0.05). This technique promises to provide an approved model for differential diagnosis of clavus and verruca. It could provide a rapid, relatively low-cost, safe and non-invasive screening tool in clinic use.
... Electrical impedance measurement can be used as a noninvasive and objective method for detecting skin tumors (Aberg et al., 2004;2005;Beetner et al., 2003;Glickman et al., 2003). Based on in vitro measurements in tumors, it was found that these tissues show an increasing conductivity and permittivity in a wide frequency range covering tens of megahertz (Jones et al., 2003;Surowiec et al., 1988). ...
Article
A new approach based on the use of interpolation for the electric potential is proposed to increase the accuracy of field calculation using the impedance method. In each voxel of a three-dimensional grid, the electric field is calculated from the potential interpolation function and is used as a solution of the continuity equation. The system of node equations is then solved and the resulting potential distribution obtained allows making the calculation of the electric field and current in each voxel. In this work, the proposed method was used to estimate the sensitivity of a tetrapolar probe in detecting small regions of increased conductivity in a stratified model of human skin. The simulations indicated that inserting a tumor in the epidermis with area 1 mm 2 and admittivity fourfold than the normal tissue the load impedance to the current source varies from about 1% while the transfer impedance shows much greater variation, about 8%. Additionally, it was found that the sensitivity of the transfer impedance shows a maximum for electrodes of 1 mm in diameter with spacing of 1.8 mm and for both impedances the sensitivity is independent of the frequency.
... Following this, Glickman YA et al. 38 in 2003 conducted an animal study which showed that electrical impedance measurements reflect morphological changes related to growth of cancerous skin lesions. EIS can be considered as an objective and non-invasive tool for differentiation between benign and malignant skin lesions. ...
Article
Bioimpedance is a term, which describes the response of living organisms to an externally applied current. It is a measure of opposition to the flow of the applied current through tissues. The measurement of bioimpedance of a living organism is non-invasive method for assessing its composition. A bioimpedance signal can be used for characterizing the tissue. The electrical properties of tissue vary with different applied frequencies. Bioimpedance is a well-established method in detecting breast cancer, cervical cancer, prostate cancer, etc. The studies showed that there are significant differences in bioimpedance between normal tissues and cancerous tissue. With this view in mind narrative review article is written to deliberate role of bioimpedance in various malignancies of the body. We also discussed studies done on oral squamous cell carcinoma (OSCC) and realized the need for more studies especially on oral potentially malignant disorders and OSCC together. The role of bioimpedance in malignancies was searched in databases such as PUBMED and SCOPUS with no restriction to the date of publication. Articles published in English medical literature on OSCC have been selected for discussion.
... 218 The measurement of electrical impedance shows the morphological changes which relate to the growth of skin cancer lesion. 219 The multifrequency impedance spectra are used to detect the electrical bioimpedance for different skin lesions. 220,221 The non-invasive probe separates the nevi from BCC with 96% sensitivity and 86% specicity. ...
Article
Full-text available
Skin cancer is the most common form of cancer and is globally rising. Historically, the diagnosis of skin cancers has depended on various conventional techniques which are of an invasive manner. A variety of commercial diagnostic tools and auxiliary techniques are available to detect skin cancer. This article explains in detail the principles and approaches involved for non-invasive skin cancer diagnostic methods such as photography, dermoscopy, sonography, confocal microscopy, Raman spectroscopy, fluorescence spectroscopy, terahertz spectroscopy, optical coherence tomography, the multispectral imaging technique, thermography, electrical bio-impedance, tape stripping and computer-aided analysis. The characteristics of an ideal screening test are outlined, and the authors pose several points for clinicians and scientists to consider in the evaluation of current and future studies of skin cancer detection and diagnosis. This comprehensive review critically analyses the literature associated with the field and summarises the recent updates along with their merits and demerits.
... One promising avenue of research for diagnosing skin cancer accurately, non-invasively, and potentially at an earlier stage is Electrical Impedance Spectroscopy (EIS) [4,5]. The living cell's membrane is semi-permeable which means it behaves similar to an electrochemical membrane. ...
Article
Full-text available
An electrical Impedance based tool is designed and developed to aid physicians performing clinical exams focusing on cancer detection. Current research envisions improvement in sensor-based measurement technology to differentiate malignant and benign lesions in human subjects. The tool differentiates malignant anomalies from nonmalignant anomalies using Electrical Impedance Spectroscopy (EIS). This method exploits cancerous tissue behavior by using EIS technique to aid early detection of cancerous tissue. The correlation between tissue electrical properties and tissue pathologies is identified by offering an analysis technique based on the Cole model. Additional classification and decision-making algorithm is further developed for cancer detection. This research suggests that the sensitivity of tumor detection will increase when supplementary information from EIS and built-in intelligence are provided to the physician.
... To overcome these limitations, researchers have developed complementary methods such as image processing and impedance measurement [8,[11][12][13][14][15], but demarcating a boundary between a benign nevus and melanoma is still uncertain [16]. This uncertainty is thought to derive from the anatomical structure of the epidermis, where there is no extracellular matrix (ECM), so melanoma tumorigenesis differs from that of other cancers [17,18]. ...
Article
Full-text available
Melanoma is visible unlike other types of cancer, but it is still challenging to diagnose correctly because of the difficulty in distinguishing between benign nevus and melanoma. We conducted a robust investigation of melanoma, identifying considerable differences in local elastic properties between nevus and melanoma tissues by using atomic force microscopy (AFM) indentation of histological specimens. Specifically, the histograms of the elastic modulus of melanoma displayed multimodal Gaussian distributions, exhibiting heterogeneous mechanical properties, in contrast with the unimodal distributions of elastic modulus in the benign nevus. We identified this notable signature was consistent regardless of blotch incidence by sex, age, anatomical site (e.g., thigh, calf, arm, eyelid, and cheek), or cancer stage (I, IV, and V). In addition, we found that the non-linearity of the force-distance curves for melanoma is increased compared to benign nevus. We believe that AFM indentation of histological specimens may technically complement conventional histopathological analysis for earlier and more precise melanoma detection.
... Previous studies suggest that histologically visible skin alterations affect the EIS (3), even below the clinically visible threshold (4) and that EIS of skin lesions correlate to histologic diagnosis (5)(6)(7). Feasibility studies indicate that EIS can be used to distinguish between skin cancer and other benign skin lesions with statistically significant accuracy (8)(9)(10)(11)(12)(13), i.e. proof-of-principle for skin cancer detection using EIS was achieved (14). However, it was concluded that additional studies are required to sufficiently develop and validate the technique with a larger number of skin lesions, and especially malignant melanomas. ...
Article
The accuracy of diagnosis of skin cancer and especially of early malignant melanoma is most important to reduce its morbidity and mortality. Previous pilot studies using electrical impedance measurements indicate statistically significant accuracies for the detection of skin cancer. The aim of this study is to investigate the accuracy of electrical impedance spectra to distinguish between malignant melanoma and benign skin lesions using an automated classification algorithm. Electrical impedance spectra were measured in a multi-centre study at 12 clinics around Europe. Data from 285 histologically analysed lesions were used to train an algorithm to sort out lesions for automatic detection of melanoma. Another data cohort of 210 blinded lesions (148 various benign lesions and 62 malignant melanomas where 38 being from Breslow thickness ≤1 mm) from 183 patients was thereafter used to estimate the accuracy of the technique. Observed sensitivity to malignant melanoma is 95% (59/62) and observed specificity 49% (72/148). The results suggest that electrical impedance spectra can distinguish between malignant melanoma and benign skin lesions. Although it is indicated that the accuracy of the device is clinically promising, the overall performance, and the sensitivity to thin malignant melanomas, must be improved and thoroughly validated before the instrument can be used as a routine stand-alone diagnostic decision support tool. The technique is under revision to further improve the reproducibility, specificity and sensitivity.
... To overcome these limitations, researchers have developed complementary methods such as image processing and impedance measurement 8, [11][12][13][14][15] , but demarcating a boundary between a benign nevus and melanoma is still uncertain 16 . This uncertainty is thought to derive from the anatomical structure of the epidermis, where there is no extracellular matrix (ECM), so that melanoma tumorigenesis differs from that of other cancers 17,18 . ...
Preprint
Full-text available
Melanoma is visible unlike other types of cancer, but it is still challenging to diagnose correctly because of the difficulty in distinguishing between benign nevus and melanoma. We conducted a robust investigation of melanoma, identifying considerable differences in local elastic properties between nevus and melanoma tissues by using atomic force microscopy (AFM) indentation of histological specimens. Specifically, the histograms of the elasticity of melanoma displayed multimodal Gaussian distributions, exhibiting the heterogeneous mechanical properties, in contrast with the unimodal distributions of elasticity in the benign nevus. We identified this notable signature was consistent regardless of blotch incidence by sex, age, anatomical site (e.g., thigh, calf, arm, eyelid, and cheek), or cancer stage (I, IV, and V). In addition, we found that the non-linearity of the force-distance curves for melanoma is increased compared to benign nevus. We believe that AFM indentation of histological specimens may technically complement conventional histopathological analysis for earlier and more precise melanoma detection.
... There have been conflicting data on the performance of EIS depending on the thickness of the melanoma. A study reported that EIS had higher sensitivity for thin or in situ melanomas (100%) than for thicker melanomas (81%) [95]; however, another study reported higher sensitivity for more invasive melanomas (100%) than for in situ melanomas (88%) [98]. ...
Article
Full-text available
With the increasing incidence of skin cancer, many noninvasive technologies to detect its presence have been developed. This review focuses on reflectance confocal microscopy (RCM), optical coherence tomography (OCT), high-frequency ultrasound (HFUS), electrical impedance spectroscopy (EIS), pigmented lesion assay (PLA), and Raman spectroscopy (RS) and discusses the basic principle, clinical applications, advantages, and disadvantages of each technology. RCM provides high cellular resolution and has high sensitivity and specificity for the diagnosis of skin cancer. OCT provides lower resolution than RCM, although its evaluable depth is deeper than that of RCM. RCM and OCT may be useful in reducing the number of unnecessary biopsies, evaluating the tumor margin, and monitoring treatment response. HFUS can be mainly used to delineate tumor depths or margins and monitor the treatment response. EIS provides high sensitivity but low specificity for the diagnosis of skin malignancies. PLA, which is based on the genetic information of lesions, is applicable for the detection of melanoma with high sensitivity and moderate-to-high specificity. RS showed high accuracy for the diagnosis of skin cancer, although more clinical studies are required. Advances in these technologies for the diagnosis of skin cancer can lead to the realization of optimized and individualized treatments.
... To overcome these limitations, researchers have developed complementary methods such as image processing and impedance measurement [8,[11][12][13][14][15],but demarcating a boundary between a benign nevus and melanoma is still uncertain [16]. This uncertainty is thought to derive from the anatomical structure of the epidermis, where there is no extracellular matrix (ECM), so that melanoma tumorigenesis differs from that of other cancers [17,18]. ...
Preprint
Full-text available
Melanoma is visible unlike other types of cancer, but it is still challenging to diagnose correctly because of the difficulty in distinguishing between benign nevus and melanoma. We conducted a robust investigation of melanoma, identifying considerable differences in local elastic properties between nevus and melanoma tissues by using atomic force microscopy (AFM) indentation of histological specimens. Specifically, the histograms of the elasticity of melanoma displayed multimodal Gaussian distributions, exhibiting the heterogeneous mechanical properties, in contrast with the unimodal distributions of elasticity in the benign nevus. We identified this notable signature was consistent regardless of blotch incidence by sex, age, anatomical site (e.g., thigh, calf, arm, eyelid, and cheek), or cancer stage (I, IV, and V). In addition, we found that the non-linearity of the force-distance curves for melanoma is increased compared to benign nevus. We believe that AFM indentation of histological specimens may technically complement conventional histopathological analysis for earlier and more precise melanoma detection.
... Importantly, the skin-electrode polarization impedance is a poorly controllable experimental factor where small alterations in skin-electrode contact area, skin humidity or temperature can give large impedance variations between measurements especially at low frequency (Alonso et al. 2020). While research has confirmed the diagnostic value of this approach (Glickman et al. 2003;Malvehy et al. 2014), it still remains unknown to what extent impedance differences detected in those studies were solely generated by changes in the underlying VCPs in cancerous skin tissues and not a secondary interface effect between skin and the electrodes. J o u r n a l P r e -p r o o f ...
Article
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Sensitive, objective, and easily applied methods for evaluating skin lesions are needed to improve diagnostic accuracy. In this study, we evaluated whether a developed noninvasive electrical impedance dermography (EID) device URSKIN could serve this purpose. In this pilot study, 17 subjects with subsequently confirmed basal cell carcinoma (BCC) underwent four-electrode EID measurements to assess the electrical properties of BCC and adjacent normal skin. A linear mixed-effects model with random intercept and slope terms was used for the analysis of multifrequency values in longitudinal and transverse directions. A significant difference in the intercept of frequency trajectories was observed for the longitudinal conductivity 0.13 S/m, p < 0.001, 95% confidence interval (CI) = 0.10 — 0.16; transverse conductivity 0.06 S/m, p < 0.001, 95% CI = 0.05 — 0.07; longitudinal relative permittivity (dimensionless) 203,742; p < 0.001, 95% CI = 180,292 — 227,191; and transverse relative permittivity (dimensionless) 86,894; p < 0.001, 95% CI = 81,549 — 92,238. Thus, our device detected significant electrical differences between BCC and adjacent normal skin. Given these preliminary performance metrics and its ease of use, this technology merits further study to establish its value in facilitating clinical diagnosis of skin cancers.
... Шведская компания-производитель SciBase AB создала ряд приборов для электроимпедансной спектроскопии (TransScan, SciBase II, SciBase III и Nevisense, SciBase AB; Stockholm, Sweden) [58,59,62,161]. Устройства оснащены автоматическим диагностическим алгоритмом, однако обученным только на 285 новообразованиях, из которых 135 меланом [61]. J. Malvehy et al. в 2012 г. в многоцентровом проспективном исследовании продемонстрировали высокие показатели чувствительности -96,6%, но при низких показателях специфичности -34,4% -для данного метода [63]. ...
Article
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Introduction. Currently, numerous studies are published by authors of different countries to demonstrate the effectiveness of noninvasive methods in the diagnosis of melanoma. Methods. A systematic search was conducted independently in the databases PubMed and Cochrane Central Register of Controlled Trials (CENTRAL) until April 2020 according to certain inclusion criteria. Data extraction was carried out independently, followed by generalization using descriptive tables. Due to the heterogeneity of the included studies and the impossibility of carrying out a meta-analysis in view of this, we performed a narrative description. Results. A total of 765 potential publications for inclusion were found and checked, of which 53 were included. By design, the studies were assigned to studies of simultaneous design – 40, to randomized clinical trials – 7, to meta-analysis – 6. Data in the included publications on 76802 skin neoplasms were reported, of which 9070 were melanomas. The extracted data were summarized in descriptive tables. Conclusion. With continuing technological progress, the development of noninvasive imaging technologies in the diagnosis of skin melanoma should follow the path of cost-effective, simple and accurate diagnosis.
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Recent optoelectronic developments have helped scientists and dermatologists to design and improve equipments for the diagnosis of skin lesions. Among the numerous techniques which can be used in dermatology, optical coherence tomography (OCT) represents one of the best options, in terms of skin penetration depth and resolution, for retrieving morphological data of the skin. However, OCT has its own limitations and cannot offer the biochemical information of the skin. These data can be obtained with fluorescence spectroscopy, a non invasive, sensitive and real time technique. The present study aims to present the advantages of combining OCT with fluorescence spectroscopy for dermatological analysis. Examples of healthy skin and lupus erythematosus recorded with these techniques are given in this paper.
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Early detection of malignant melanoma remains the key factor in lowering mortality from this cancer. Recognizing the importance of this issue 25 years ago, our group at New York University published in CA: A Cancer Journal for Clinicians the mnemonic “ABCD” to facilitate the early diagnosis of melanoma. Studies have demonstrated the usefulness of this paradigm in enhancing early melanoma diagnosis as a part of clinical examinations, mass screenings, and public education programs. Approaches to melanoma diagnosis have dynamically evolved during the ensuing quarter century. In the 1990s, dermoscopy enabled the recognition of new subsurface features to differentiate between malignant and benign pigmented lesions. During the last decade, new computer-based technologies have improved diagnostic sensitivity and specificity and may result in optimizing lesion selection for biopsy and pathology review. Despite all of the advances in melanoma diagnosis, timely recognition, detection, and rapid treatment of melanoma remain critical. Although pathologic examination remains the gold standard for diagnosis, this cancer has the potential to be diagnosed through noninvasive approaches because of its cutaneous location. From the development of the ABCDs through current attempts that use complex computer algorithms and genetic markers, a clinician's ability to detect melanoma in its earliest form has been augmented. However, a “good clinical eye” is still fundamental to selecting the lesions for evaluation among the sea of those that are prevalent. As current approaches are refined and new techniques are developed, the improved ability to diagnose this cancer will hopefully enhance reaching the goal of reducing melanoma mortality. CA Cancer J Clin 2010. © 2010 American Cancer Society, Inc.
Conference Paper
To support early diagnosis of skin cancer and minimize the risk of developing metastases, electrical impedance tomography (EIT) is a promising technique. EIT is a bio-medical technique for imaging the electrical conductivity distribution of a body segment. The aim of this study is to adapt an EIT system for skin cancer screening. A 3-D finite element model (FEM) of the skin was first developed. This model was used to study the electrical behavior of cutaneous layers and identify the operating frequencies to properly discriminate malignant from benign lesions. Simulated data obtained with the FEM model were used to develop image reconstruction algorithms for visualizing and discriminating skin lesions. Furthermore, according to the specifications obtained from the model, electronic circuits and a handheld probe incorporating a disposable 16-electrode array were designed and built. The system and reconstruction algorithms were validated in vitro and measurements showed great correlation with simulations.
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Early detection of melanoma remains crucial to ensuring a favorable prognosis. Dermoscopy and total body photography are well-established noninvasive aids that increase the diagnostic accuracy of dermatologists in their daily routine, beyond that of a naked-eye examination. New noninvasive diagnostic techniques, such as reflectance confocal microscopy, multispectral digital imaging and RNA microarrays, are currently being investigated to determine their utility for melanoma detection. This review presents emerging technologies for noninvasive melanoma diagnosis, and discusses their advantages and limitations.
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Confirming a diagnosis of cutaneous melanoma requires obtaining a skin biopsy specimen. However, obtaining numerous biopsy specimens-which often happens in patients with increased melanoma risk-is associated with significant cost and morbidity. While some melanomas are easily recognized by the naked eye, many can be difficult to distinguish from nevi, and therefore there is a need and opportunity to develop new technologies that can facilitate clinical examination and melanoma diagnosis. In part I of this 2-part continuing medical education article, we will review the practical applications of emerging technologies for noninvasive melanoma diagnosis, including mobile (smartphone) applications, multispectral imaging (ie, MoleMate and MelaFind), and electrical impedance spectroscopy (Nevisense). Copyright © 2015 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.
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The electrical properties of biological cells have connections to their pathological states. Here we present an electric impedance microflow cytometry (EIMC) platform for the characterization of disease states of single cells. This platform entails a microfluidic device for a label-free and non-invasive cell-counting assay through electric impedance sensing. We identified a dimensionless offset parameter δ obtained as a linear combination of a normalized phase shift and a normalized magnitude shift in electric impedance to differentiate cells on the basis of their pathological states. This paper discusses a representative case study on red blood cells (RBCs) invaded by the malaria parasite Plasmodium falciparum. Invasion by P. falciparum induces physical and biochemical changes on the host cells throughout a 48-h multi-stage life cycle within the RBC. As a consequence, it also induces progressive changes in electrical properties of the host cells. We demonstrate that the EIMC system in combination with data analysis involving the new offset parameter allows differentiation of P. falciparum infected RBCs from uninfected RBCs as well as among different P. falciparum intraerythrocytic asexual stages including the ring stage. The representative results provided here also point to the potential of the proposed experimental and analysis platform as a valuable tool for non-invasive diagnostics of a wide variety of disease states and for cell separation.
Article
Emerging tools for the diagnosis of skin cancer are non-invasive imaging devices that allow for skin visualization without biopsy. While the capabilities of non-invasive imaging tools are far-reaching, each varies in its resolution depth, image clarity, clinical applicability, accuracy, sensitivity, and specificity. The objective of this review is to evaluate non-invasive imaging modalities, and examine their capabilities, conditions for use, clinical applications, and limitations. A literature review was conducted on Pubmed using the search term "non-invasive diagnostic imaging tools and skin". Relevant citations suggested by Pubmed were included. Each non-invasive imaging tool evaluated was also used as a search term along with the word "skin". While some tools are meant to be aids to histology like dermoscopy and optical coherence tomography, other tools, like confocal microscopy and tape stripping mRNA, show the potential to surpass histology and become the new "gold standard". Experience with use of these instruments plays a large role in their utility value. While digital multispectral dermoscopy is able to generate a diagnosis, other tools like dermoscopy and confocal microscopy require learning and clinical experience. A search was conducted using only one search engine. Only English language articles were considered. How useful these tools are to dermatologists is dependent on their understanding of how the tools can aid them in diagnosis and their confidence in the results. Further research in this field will solidify non-invasive imaging tools as reliable tools in skin cancer diagnosis.
Chapter
Hyperthermia is a medical heat-treatment, widely used in various medical fields and has a well-recognized effect in oncology. It is an ancient treatment. However, when making hyperthermia we are limited by numerous biological, physical/technical and physiological problems. The word hyperthermia means increased temperature by heating of tumors. This relatively simple, physical-physiological method has a phoenix-like history with some bright successes and many deep disappointments. Why is this enigma? What do we have in hand? Answers lie in the applied techniques.
Article
Finite element modeling of the skin is useful to study the electrical properties of cutaneous tissues and gain a better understanding of the current distribution within the skin. Such an epithelial finite element model comprises extremely thin structures like cellular membranes, nuclear membranes, and the extracellular fluid. Meshing such narrow spaces considerably increases the number of elements leading to longer computing time. This also greatly reduces the number of epithelial cells that can be assembled before reaching computing limitations. To avoid the problem of meshing extremely narrow spaces while unnecessarily increasing the number of elements, we present a new hybrid modeling approach to develop a 3-D finite element model of the skin. This skin model comprises all skin layers, different lesion types, and a complete electrode model. It is used to analyze the complex electrical behavior of normal and malignant skin tissues. The current distribution within this model is also simulated to assess the depth of field achievable by an electrical impedance tomography system at different operating frequencies.
Article
We present initial results on the fabrication and testing of micropatternable conductive nanocomposite polymer (C-NCP) electrodes for tissue impedance measurements. We present these proof-of-concept results as a first step toward the realization of our goal: an improved Electrical Impedance Scanning (EIS) system, whereby tissue can be scanned for cancerous tissue and other anomalies using large arrays of highly flexible microfabricated electrodes. Previous limitations of existing EIS system are addressed by applying polymer based microelectromechanical system (MEMS) technology. In particular, we attempt to minimize mechanical skin contact issues through the use of highly compliant elastomeric polymers, and increase the spatial resolution of measurements through the development of microelectrodes that can be micropatterned into large, highly dense arrays. We accomplish these improvements through the development of C-NCP electrodes that employ silver nanoparticle fillers in an elastomer polymer base that can be easily patterned using conventional soft lithography techniques. These new electrodes are tested on conventional tissue phantoms that mimic the electrical characteristics of human tissue. We characterize the conductivity of the electrodes (average resistivity of 7x10-5 ohm-m +/- 14.3% at 60 wt-% of silver nanoparticles), and further employ the electrodes for impedance characterization via Cole-Cole plots to show that measurements employing C-NCP electrodes are comparable to those obtained with normal macroscopic metal electrodes. We also demonstrate anomaly detection using our highly flexible Ag/AgCl C-NCP electrodes on a tissue phantom.
Article
The measurement of electrical impedance of skin using surface electrodes permits the assessment of changes in local properties of the skin and can be used in the detection of tumors. The sensitivity of this technique depends mainly on the geometry of the probe and the size of the tumor. In this article, the impedance method was used to estimate the sensitivity of a tetrapolar probe in detecting small regions of increased conductivity in a stratified model of human skin. The impedance method was used to model the potential distribution using fasorial analysis to solve the node equations of the equivalent circuit. Interpolation was applied to reduce discretization error. The skin was modeled as a three-layer structure with different conductivity and permittivity obtained from the literature. A tumor was modeled as a small volume with admittivity four times higher than the normal tissue. Sensitivity calculation was made as a function of electrode diameter and separation, tumor size, and excitation frequency. The simulations indicated that by inserting a one square millimeter tumor in the epidermis, the load impedance to the current source varies about 1% while the transfer impedance varied 8%. The sensitivity also increases nonlinearly with increasing tumor area and thickness. Additionally, it was found that the sensitivity of the transfer impedance has a maximum value when the electrodes are separated by 1.8 mm. The results show that transfer impedance measurements of the skin may detect small skin tumors with a reasonable sensitivity by using an appropriate tetrapolar probe.
Article
Skin offers easy access, convenience and non-invasiveness for drug delivery and diagnosis. In principle, these advantages of skin appear to be attractive for critically ill patients given potential difficulties that may be associated with oral and parenteral access in these patients. However, the profound changes in skin physiology that can be seen in these patients provide a challenge to reliably deliver drugs or provide diagnostic information. Drug delivery through skin may be used to manage burn injury, wounds, infection, trauma and the multisystem complications that rise from these conditions. Local anaesthetics and analgesics can be delivered through skin and may have wide application in critically ill patients. To ensure accurate information, diagnostic tools require validation in the critically ill patient population as information from other patient populations may not be applicable.
Article
An early diagnosis of cutaneous malignant melanoma is of high importance for good prognosis. An objective, non-invasive instrument could improve the diagnostic accuracy of melanoma and decrease unnecessary biopsies. The aim of this study was to investigate the use of Near-infrared and skin impedance spectroscopy in combination as a tool to distinguish between malignant and benign skin tumours. Near-infrared and skin impedance spectra were collected in vivo on 50 naevi or suspect melanomas prior to excision. Received data were analysed using multivariate techniques and the results were compared to histopathology analyses of the tumours. A total of 12 cutaneous malignant melanomas, 19 dysplastic naevi and 19 benign naevi were included in the study. The observed sensitivity and specificity of the proposed method were 83% and 95%, respectively, for malignant melanoma. The results indicate that the combination of near-infrared and skin impedance spectroscopy is a promising tool for non-invasive diagnosis of suspect cutaneous malignant melanomas.
Article
Managing the balance between accurately identifying early-stage melanomas while avoiding biopsies of benign lesions (i.e. over-biopsy) is the major challenge of melanoma detection. Decision-making can be especially difficult in patients with extensive atypical nevi. Recognizing that the primary screening modality for melanoma is subjective examination, studies have shown a tendency towards over-biopsy. Even low-risk routine surgical procedures are associated with morbidity, mounting healthcare costs, and patient anxiety. Recent advancements in noninvasive diagnostic modalities have helped to improve diagnostic accuracy, especially when managing melanocytic lesions of uncertain diagnosis. Breakthroughs in artificial intelligence have also shown exciting potential in changing the landscape of melanoma detection. In part I of this continuing medical education article, we review novel diagnostic technologies such as automated 2D and 3D total body imaging with sequential digital dermoscopic imaging, reflectance confocal microscopy, and electrical impedance spectroscopy, and we explore the logistics and implications of potentially integrating artificial intelligence into existing melanoma management paradigms.
Article
Compared with traditional open surgery, minimally invasive surgery (MIS) improves the accuracy and dexterity of a surgeon and minimizes trauma to the patient. However, the lack of significant haptic feedback in MIS can make tumor localization difficult. A noninvasive electrical impedance probe (NEIP), consisting mainly of two spherical electrodes and a constant force generator, has been developed to gently touch or slide over tissue surface and at the same time record impedance values without prior registration of the surface. We prove that there is a linear relationship between the surgical margin width and the recorded conductance. Ex vivo experiments in ten human kidney specimens were performed to demonstrate the feasibility of NEIP. The experimental results verify the linear relationship and indicate that NEIP can provide accurate tumor location while sliding over the tissue surface.
Article
Conventional methods of electrobioimpedance imaging are not suited for adequate visualization of the Skin Electrical Impedance landscape (SEL) because they do not provide high spatial resolution at large enough area of view. The Skin Electrodynamics Introscopy (SEI) enabled dynamic spectral imaging of the SEL at 32×64 mm2 area with 1mm spatial resolution. The focus of the study was to investigate the SEL distinguishing features between early and advanced-stage cancer at the model object of melanoma and its satellite. The analysis of the test-induced SEL metamorphoses was carried out at the periods of blood-stop and blood-restoration. It was found that the young tumor could be reliably visualized and distinguished by its antiphase hypoxia-induced response as compared to that of the advanced one. In response to the blood-restoration, an appearance of newly formed SEL clusters pointed out apparently at vascular abnormalities associated with the tumor. Similar SEL clusterization can be supposedly expected in response to any other test factors which affect cell permeability or/and blood viscosity. The proposed approach might be useful for more thorough mapping and staging malignancies.
Article
As a result of increasing melanoma incidence and challenges with clinical and histopathologic evaluation of pigmented lesions, noninvasive techniques to assist in the assessment of skin lesions are highly sought after. This review discusses the methods, benefits, and limitations of adhesive patch biopsy, electrical impedance spectroscopy (EIS), multispectral imaging, high-frequency ultrasonography (HFUS), optical coherence tomography (OCT), and reflectance confocal microscopy (RCM) in the detection of skin cancer. Adhesive patch biopsy provides improved sensitivity and specificity for the detection of melanoma without a trade-off of higher sensitivity for lower specificity seen in other diagnostic tools to aid in skin cancer detection, including EIS and multispectral imaging. EIS and multispectral imaging provide objective information based on computer-assisted diagnosis to assist in the decision to biopsy and/or excise an atypical melanocytic lesion. HFUS may be useful for the determination of skin tumor depth and identification of surgical borders, although further studies are necessary to determine its accuracy in the detection of skin cancer. OCT and RCM provide enhanced resolution of skin tissue and have been applied for improved accuracy in skin cancer diagnosis, as well as monitoring the response of nonsurgical treatments of skin cancers and the determination of tumor margins and recurrences. These novel approaches to skin cancer assessment offer opportunities to dermatologists, but are dependent on the individual dermatologist’s comfort, knowledge, and desire to invest in training and implementation of noninvasive techniques. These noninvasive modalities may have a role in the complementary assessment of skin cancers, although histopathologic diagnosis remains the gold standard for the evaluation of skin cancer.
Chapter
Bioimpedance is described as the response of living organisms to an external current. It is an amount of obstruction to the flow of the external current through the tissues. Bioimpedance is a noninvasive method for evaluating the structure of a living organism. A bioimpedance signal can be used for describing the tissues. Bioimpedance of a tissue differs with different applied frequencies. It is an established technique in detection of breast cancer, cervical cancer, prostate cancer, and other cancers. There are evidences that significant differences exist between bioimpedance of normal and malignant tissue. With this view in mind, a comprehensive description of the technique is hereby given to deliberate the role of bioimpedance with a special emphasis on oral cancer. We have also discussed the studies carried out on oral potentially malignant disorders (OPMDs) and oral squamous cell carcinoma (OSCC) and realized the necessity for more studies especially on OPMDs and OSCC together.
Chapter
Electrical impedance spectroscopy (EIS) has been used in dermatology in the last decades for the study of inflammatory dermatosis and skin tumours. Multiple applications in the study of contact dermatitis and atopic eczema have been proposed. More recently NevisenseR (SCIBASE, Sweden), a device using EIS received the approval for the application in the detection of malignant melanoma with CE marked in Europe, has TGA approval in Australia, and now also a FDA clearance in the United States. In this chapter, we review the principles of EIS, the research in recent years, the device approved for clinical use, the examination procedure and EIS evidence within dermatology.
Article
Identifying and localizing of deep pulmonary nodules are among the main challenges that thoracic surgeons face during operations, particularly in thoracoscopic procedures. To facilitate this, we have tried to introduce a non-invasive and safe method by measuring the lung electrical bio-impedance spectrum with a four-electrode array sensor. To study the feasibility of this method, since any change in the depth or diameter of the nodule in the lung tissue is not practical, we used the finite element modeling of the lung tissue and pulmonary nodule to allow changes in the depth and diameter of the nodule, as well as the distance in between the injection electrodes. Accordingly, a bio-impedance sensor was designed and fabricated. By measuring the electrical impedance spectrum of pulmonary tissues in four different specimens with a frequency band of 50 kHz to 5 MHz, 4 pulmonary nodules at four different depths were identified. The obtained bio-impedance spectrum from the lung surface showed that the magnitude and phase of electrical bio-impedance of the tumoral tissue at each frequency is smaller than that of the healthy tissue. In addition, the frequency characteristic varies in the Nyquist curves for tumoral and healthy lung tissues.
Article
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.
Article
Intraoperative localization of small and in-depth pulmonary nodules particularly during video-assisted thoracoscopic surgery (VATS), is one of the main challenges for Thoracic surgeons. Failure to determine the location of nodules may lead to a large incision in the normal lung tissue or the conversion of the minimally invasive surgery to an open thoracotomy. The aim of this study is to evaluate the use of electrical bio-impedance measurement to precisely determine the position of in-depth pulmonary nodules and tumors, which are not visible during thoracoscopic surgeries or even are not palpable during open thoracic surgeries. With this regard, a suitable bio-impedance sensor similar to a biopsy forceps has been designed in order to measure the lung tissue bio-impedance. Using the available data on the electrical properties recorded from lung tissue during inhalation and exhalation, combined with the tumor modeling in COMSOL software, the effect of different parameters including the size and depth of tumor and the relative difference of electrical properties between healthy and tumoral tissue has been assessed. Furthermore, the geometric characteristics of the proposed sensor are considered. The results generally verify that larger size of nodules results in an easier distinguishing process. Additionally, it is worthy to note that applying a larger geometrically sensor is essential to detect the small and in-depth nodules.
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Background: Electrical impedance spectroscopy (EIS) is a non-invasive diagnostic technique that measures tissue impedance. Objectives: This prospective study, conducted at 2 centres in Australia, aimed to evaluate the effect of adding an EIS measurement at baseline to suspicious melanocytic lesions undergoing routine short-term sequential digital dermoscopy imaging (SDDI) METHODS: Patients presented with suspicious melanocytic lesions that were eligible for short-term SDDI (with no clear feature of melanoma on dermoscopy). The EIS measurement was performed at the first visit following the dermoscopic photography. Normally, an EIS score of ≥4 is considered positive whereas this protocol investigated a higher cut-off in combination with SDDI. When the EIS score was ≥7 the lesion was excised immediately due to the high risk of melanoma. Lesions with a score <7 were monitored with standard SDDI over a 3 month period. Results: From a total of 160 lesions analysed, 128 of 154 benign lesions received an EIS score of 0-6, giving a specificity of the EIS method for the diagnosis of melanoma of 83.1% (95% CI:76.3-88.7). Five of the six melanomas found in this study had an EIS score ≥7, with a sensitivity for melanoma diagnosis of 83.3% (95% CI:35.9-99.6). When EIS 0-6 lesions were subsequently followed up with SDDI, one additional melanoma was detected (EIS=6) giving the sensitivity for the diagnosis of melanoma overall of 100%: 95% CI:54.1-100 (6/6 MM excised) and the specificity 69.5%: 95% CI:61.5 to 76.6 (107/154 benign lesions not excised). Conclusion: If utilizing a protocol where an EIS score ≤3 requires no SDDI and ≥7 requires immediate excision this reduced the need for SDDI by 46.9% (75/160): 95% CI:39.0-54.9. This article is protected by copyright. All rights reserved.
Article
Tissue electrical conductivity measurements are very important for diagnostic purposes. In this paper, an electrical bio-impedance sensor with a biopsy forceps shape was introduced for measuring electrical conductivity of the tissue inside the body. For this purpose, based on the Laplaces. equation and the forced boundary conditions in the mouth of the forceps, the relation between electrical conductivity of the tissue and measured electrical potential was analytically obtained. The obtained analytical formula was verified by modeling the electrical bio-impedance forceps and biological tissue in COMSOL software. A prototype of the designed bio-impedance forceps was fabricated and experimentally validated. The validation process was performed by measuring electrical conductivity of the Phosphate -Buffered Saline (PBS) solution with different concentrations. Finally, by measuring electrical impedance spectrum of pulmonary tissues in three different samples at a frequency band of 50 kHz to 5 MHz, it was found that this sensor could be potentially beneficial to discriminate tumoral tissues from healthy ones in biopsy process.
Conference Paper
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Initial physical examination in dermatology is often based on visual inspection and clinical experience, supported by technologically simple devices such as the dermatoscope. While such devices can be rather effective in trained hands, they cannot provide objective measurement data and error margins. We propose a specific adaptation of electrical impedance tomography scanning, a technology which has proven its value in other medical disciplines, as a support tool for dermatological physical examination and -eventually- diagnosis. A proof of concept prototype of the DermaSense device has been constructed and is currently being evaluated, while clinical pilot measurements related to melanoma are being planned.
Article
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Skin cancer is a dangerous disease causing a high proportion of deaths around the world. Any diagnosis of cancer begins with a careful clinical examination, followed by a blood test and medical imaging examinations. Medical imaging is today one of the main tools for diagnosing cancers. It allows us to obtain precise images, internal organs and thus to visualize the possible tumours that they present. These images provide information on the location, size and evolutionary stage of tumour lesions. Automatic classification of skin tumours using images is an important task that can help doctors, laboratory technologists, and researchers to make the best decisions. This work has developed a classification model of skin tumours in images using Deep Learning with a Convolutional Neural Network based on TensorFlow and Keras model. This architecture is tested in the HAM10000 dataset consists of 10,015 dermatoscopic images. The results of the classification of the experiment show that the accuracy was achieved by our model, which is in order of 94.06% in the validation set and 93.93% in the test set.
Article
Lung cancer is the most common and lethal cancer in many parts of the world. The establishment of lung cancer screening by low-dose computerized tomography (CT) scan has led to finding lung cancers in early stages as very small nodules. However, finding those nodules, particularly when located deep in the lung parenchyma, could be impossible during lung surgeries without preoperative or intraoperative localization. This study introduces a simple and safe method having the potential to localize in-depth pulmonary nodules intraoperatively. In this regard, a bioimpedance probe with four spherical electrodes was designed and built. By an in vitro study, the bioimpedance data of 286 lung tissue samples obtained from 38 patients in a frequency range of 50 kHz–5 MHz were collected and analyzed with Nyquist curves and boxplot charts. Finally, a smart system was designed based on the bioimpedance phase and magnitude to differentiate healthy lung tissue from the tumoral lung tissue. Our proposed system consists of two parts: the feature reduction with principal component analysis (PCA) and the classification with support vector machine (SVM), linear discriminant analysis (LDA), and K-nearest neighbors (KNN). Classifier analysis showed that the accuracy of all classifiers was more than 95% for 15 principal components; the SVM classifiers had the highest accuracy above 98%. This research sheds light on the feasibility of designing a real-time, safe, and smart system to localize the invisible/impalpable pulmonary nodules by the bioimpedance spectrum of the lung tissue.
Chapter
There are some basic physiological factors connected to the heating phenomena. Two of them are essential for heating: the metabolic rate, which generates additional heat to the external energy intake, and the heat sinks (mainly the blood flow) cooling effectively the locally heated volume. The absorbed energy from outside energy sources is measured by the specific absorption rate [SAR, W/kg]. The SAR increases the temperature but due to the cooling of the physiologically regulated blood stream this heating mechanism is very complex and the temperature is definitely lower than in a regular phantom without a blood stream, even if the phantom material fits well to the targeted real tissues.
Article
This paper presents a label-free and noninvasive cell-counting assay system for electrical diagnostic tests of Falciparum malaria using electric impedance spectroscopy (EIS). Our system enabled a high-throughput test in a compact form-factor by the integration of a microfluidic device and a custom circuit board. Based on the differentiation of dielectric properties between cells and container medium, the target cells were individually detected by surface charge density and disease state. [1] This method suggests a potential electrical diagnostic test for malaria in portable electronics.
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The present paper is aimed to better illustrate the possible association between a particular extremely weak field, the air ions, and the human health response to this solicitation. Methods and instruments for this kind of analysis are here given in the form of a project: a “Ions meter”, to reveal and characterize the properties of the air ions, and “APEC 300”, an advanced electronic device. Both instruments are endowed with a high power of resolution (HPR). APEC 300 can give the response to the possible health effects by measurements of two electrocuteaneous parameters: the potential level and the impedance. The power of resolution of APEC 300 is much higher than that of other usual devices, for instance, the EAV ones (electroacupuncture); this instrument will be completely ready within few weeks.
Article
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We critically review bulk electrical properties of tissues and other biological materials, from DC to 20 GHz, with emphasis on the underlying mechanisms responsible for the properties. We summarize the classical principles behind dielectric relaxation and critically review recent developments in this field. Special topics include a summary of the significant recent advances in theories of counterion polarization effects, dielectric properties of cancer vs. normal tissues, properties of low-water-content tissues, and macroscopic field-coupling considerations. Finally, the dielectric properties of tissues are summarized as empirical correlations with tissue water content in other compositional variables; in addition, a comprehensive table is presented of dielectric properties. The bulk electrical properties of tissues are needed for many bioengineering applications of electric fields or currents, and they provide insight into the basic mechanisms that govern the interaction of electric fields with tissue.
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The goal of our study was to assess the value of both scintimammography with 99mTc-sestamibi (SMM) and trans-scan (T-scan) in detecting breast cancer. A total of 121 women were evaluated by palpation, mammography, SMM and T-scan. SMM was performed in the prone, breast dependent position. Immediate and delayed views (double-phase) were obtained. T-scan is a new breast imaging method that maps noninvasively the distribution of tissue electrical impedance and capacitance. SMM had 88.9% sensitivity, 88.4% specificity and 88.4% accuracy in detecting breast cancer. SMM had 100% sensitivity in detecting breast tumors >1 cm and only 66% sensitivity in detecting tumors <1 cm. T-scan had 72.2% sensitivity and 67% specificity in detecting breast cancer. It detected one more breast cancer than SMM, at the expense of 27 additional false-positive results. Double-phase SMM was sensitive and specific in detecting breast cancer. This method may reduce the rate of negative breast biopsies in tumors >1 cm. T-scan was only moderately accurate in detecting breast cancer. Its addition to SMM did not improve significantly the rate of breast cancer detection. However, because of its complete noninvasiveness, large-scale applicability and low cost, T-scan deserves further refining.
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Differentiation between inflammatory and malignant lymph nodes by ultrasound is difficult. Electrical impedance scanning (EIS) is a new diagnostic tool, so far used primarily for the identification of malignant breast lesions. Cancer cells have altered dielectric properties compared with normal cells, thereby distorting the local electrical field. The induced changes in capacitance and conductivity are measurable using EIS. We evaluated EIS in demonstrating the cause of lymph node enlargement. 51 lymph nodes that were suspicious for malignancy on ultrasound (32 patients, mean age 32 years), with a mean size of 18 mm x 12 mm x 10 mm, were examined. The following lymph node locations were included in the study: cervical, inframandibular, axillary, paraaortic and inguinal. EIS results were compared with histopathological and follow-up findings. 30/34 malignant lymph nodes were correctly detected using EIS, while 14/17 inflammatory or benign lymph nodes were correctly identified as benign by EIS; thus, there were 4/51 false negative and 3/51 false positive cases. The sensitivity was 88.2% and the specificity was 82.4%. Corresponding negative and positive predictive values were 77.8% and 90.9%, respectively. Results from this initial study suggest the potential usefulness of EIS as an adjunctive imaging modality in the differentiation of lymphadenopathy that is equivocal on ultrasound. The best accuracy was obtained in the cervical, axillary and inguinal regions. Owing to technical restrictions of the present system, examination of inframandibular and paraaortic lymph nodes should be limited to special cases.
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In this paper we present the T-SCAN technology and its use as a diagnostic tool for breast cancer detection. We show, using theoretical models with simplified geometries, that displaying planar two-dimensional maps of the currents detected at the breast's surface relate to the electric field distribution within the breast. This distribution is a manifestation of the bulk spatial inhomogeneities in the complex dielectric constant that represent the various tissue types. These differences may be used to discriminate between various pathological states. We furthermore illustrate a useful classifier, based on admittance data measured up to 2 kHz, and we argue that low frequency impedance measurements can be used successfully in breast cancer diagnosis.
Article
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Early recognition of melanoma is the key in preventing metastatic disease. The aim of this study was to evaluate diagnostic ability of general practitioners (GPs) and dermatologists concerning pigmented skin lesions in general and melanoma in particular. We also investigated whether the diagnostic ability of GPs changed after a lecture on melanoma. A test set of 13 pigmented skin lesions on 35-mm color slides was presented to 160 GPs and 60 dermatologists during educational courses. GPs correctly evaluated biologic behavior of the pigmented skin lesions in 72% of the evaluations. In 71% of these evaluations they correctly identified the lesions. The proportion of lesions correctly identified was positively correlated with the frequency of pigmented skin lesions in everyday practice. Dermatologists made a correct identification of the lesions in 88% of all evaluations, and they correctly evaluated biologic behavior in 94% of these. Recognition of melanoma was proportional to melanoma exposure in everyday practice. Thick melanomas were better recognized than thin melanomas in both physician groups. After a lecture on melanoma, sensitivity of GPs to recognize malignant disease increased from 72% to 84%, without a significant decrease in specificity. The proportion of lesions correctly identified also rose significantly (66% vs 52%).
Article
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One of the problems facing anyone attempting the investigation of dielectric properties of living tissue is the presence of skin, which screens all that lies under it from direct measurement. Thus, in non-invasive breast examination using transimpedance measurements, skin parameters heavily influence the results, specifically at low (less than 10 kHz) frequencies. In this paper a method for overcoming this difficulty by using multi-frequency measurements obtained from a surface current distribution over a flat probe is described. By using the variation in the shape of the real and imaginary parts of the surface current density at different frequencies, the original dielectric values of the skin and the underlying tissue can be obtained, based on the assumption of the existence of a two-layer geometry, with the upper (skin) layer much thinner than the lower (tissue) layer. The results obtained can be used in the diagnosis of breast cancer using existing transimpedance measurement devices.
Article
The aim of this study was to quantify the clinical value of using electrical impedance scanning (EIS) as an adjunct to other diagnostic techniques in order to identify cancerous tissue based upon its inherent altered local dielectric properties. 210 consecutive women with 240 sonographically and/or mammographically suspicious findings were examined using EIS. All lesions were histologically-proven. 86/103 malignant and 91/137 benign lesions were correctly identified using EIS (87.8% sensitivity, 66.4% specificity). NPV and PPV of 84.3% and 65.2% were observed, respectively. Excluding cases as defined by a priori criteria, i.e. lesions located deeper than 35 mm, lesions larger than 35 mm, and retroareolar lesions, a sensitivity of 85.5% was observed, and for invasive cancers, 91.7%. The detection rate for ductal carcinoma in situ (DCIS) was poor (57.1%, n=14). By adding EIS to mammography and ultrasound, the sensitivity rose from 86.4 to 95.1%, whereas the accuracy decreased from 82.3 to 75.7%. EIS appears to be of interest as an adjunct to breast diagnostic techniques, performing with a reasonable sensitivity. Further investigations on histomorphological characteristics and the reasons for false-negative findings are essential to gain further knowledge about the bioelectricity of breast lesions, and prove the value of this new technology.
Article
Electrical bioimpedance can reflect structural and chemical changes of the skin and the oral mucosa in the β-dispersion frequency range. From our measured multifrequency data set, four physically distinct indices have been formulated to distinguish the electrical properties for different anatomical locations and to detect different reactions and conditions of the skin and the oral mucosa. In comparison with the skin, the differences for various anatomical regions were greater in the oral cavity, which showed as well a different impedance pattern after irritant responses. We conclude that the impedance technique is able to classify and quantify different responses and conditions, preferably by using contralateral reference sites, or following a site in time; however, mapping of baseline properties facilitates the use of the method even if a large part of the skin or the oral mucosa is involved. The method has the potential of becoming a diagnostic decision support tool.
Article
A set of 120 impedivity spectra was collected in breast tissue immediately after excision from 64 patients undergoing breast surgery. The measurements were made at 12 discrete frequencies halving from 1 MHz to 488 Hz. The spectra were sorted into three groups of normal tissue, mammary gland, connective tissue and adipose tissue, and three groups of pathological tissue, mastopathy, fibroadenoma and carcinoma. Intergroup multiple comparisons of the components of impedivity and admittivity were systematically carried out at every measurement frequency. The low-frequency-limit resistivity, the fractional power and characteristic frequencies were calculated from the experimental data. No significant correlation between impedivity and admittivity and patient's age was observed, except for mastopathy. No significant difference between groups of normal tissue and benign pathology (mammary gland, mastopathy and fibroadenoma) was found. The group of carcinoma differed from all the other groups principally by the low-frequency-limit resistivity, the fractional power and the phase angle at frequency above 125 kHz. These results indicate that impedance spectroscopy is appropriate for the detection of breast cancer. Keywords: electrical impedance spectroscopy, impedivity, admittivity, excised tissue, breast cancer
Article
More efficient screening for breast cancer can lead to a reduction in the need for radical surgery and improved survival rates. Modern technology, particularly electronics and computerized instrumentation, makes such improvement feasible. We have developed an instrument for screening for breast cancer based on measuring the dielectric properties of tissues. An image of the electric properties of the breast is presented on a monitoring screen, using 512 'pixels', from which it is possible to distinguish pathological tissue. The image can be recalled on the monitor at will. The test can be performed by paramedical personnel. In the present study 6000 patients were tested with this instrument; 745 of these have undergone biopsy and these had been tested with all available instrumentation. A number of cases were found in which only this instrument detected a pathology which proved malignant. Instruments of such a type could become an additional part of breast cancer clinics.
Article
A new impedance analytical system was developed, and measurements were performed over a frequency range of 0-200 kHz by the three-electrode method. The three electrodes consist of a coaxial needle electrode inserted into the tumor and a large reference electrode on the upper abdominal wall. The electrical bio-impedance was measured in 54 patients with breast tumors. The biological tissue can be regarded electrically as an equivalent consisting of extracellular resistance (Re), intracellular resistance (Ri), and electrical capacitance of the cell membrane (Cm). These three parameters were calculated from the measured values of electrical bio-impedance by the curve-fitting technique using a computer program. It was found that Re and Ri of breast cancers were significantly higher than those of benign tumors (p less than 0.01), and that Cm of breast cancers was significantly lower than that of benign tumors (p less than 0.01). Measurement of the electrical bio-impedance of breast tumors may have value in the differential diagnosis of breast lesions.
Article
Relative permittivity of infiltrating breast carcinoma and the surrounding tissue was measured. The experiments were performed at frequencies from 20 kHz to 100 MHz at 37 degrees C using an automatic network analyzer and an end-of-the-line capacitive sensor. Cole-Cole dielectric parameters were calculated by curve fitting using a computer program. Three main categories of tissues were considered: the central part of the tumor, the tumor surrounding tissue, and the peripheral tissue. Within each category, the large spread of the dielectric data for different specimens suggests structural and cellular inhomogeneities of the tumor tissue. However, certain consistency has been found in the dielectric relaxation time and the coefficient of the distribution of the relaxation time within each category. The results seem to indicate that RF impedance imaging can potentially be used as a diagnostic modality for the detection of human breast carcinoma.
Article
We estimated the prevalence of persons with histologic dysplasia in at least one of two nevi examined by biopsy to be 53% in Utah's caucasians. This apparently high prevalence indicates that such lesions may represent a normal variant of a melanocytic nevus, perhaps those in the process of active proliferation. Regardless of the apparent ubiquity of these lesions, examination of biopsy specimens led to a grading scheme of histologic dysplasia that may reflect chronologic stages in the neoplastic development of melanocytic nevi. Comparison of these histologic findings with the clinical examination yielded the unexpected result that dysplasia and lesion size are independent of each other. Lesions 3 mm in diameter or smaller were as likely to be dysplastic as those much larger. There was, however, a statistically significant relationship between histologic dysplasia of a nevus examined by biopsy and the person's total number of melanocytic lesions. This finding indicates that the pathology grading scheme may be useful. The high prevalence of dysplastic nevi dilutes the clinical significance of a dysplastic nevus as an isolated finding and thereby lessens the importance of pathologic findings in the diagnosis of dysplastic nervus syndrome.
Article
A prospective, community practice-based, clinicopathologic correlation was undertaken in 165 melanocytic nevi excised from a group of forty-three patients, each patient having previously had at least one clinically suspected and histologically confirmed dysplastic melanocytic nevus. Eighty-two percent of seventy-two lesions with histologic evidence of mild dysplasia had been diagnosed correctly as such clinically. The accuracy of clinical diagnosis of moderate dysplasia was low (20%); however, all cases of severe dysplasia with or without in situ melanoma were diagnosed correctly. In 75% of all cases in which dysplasia of any degree was diagnosed clinically, histologic evidence of dysplasia was found. In order to investigate further the clinical features of these nevi, 175 color enlargements of histologically confirmed dysplastic melanocytic nevi were examined. The following clinical features were found to be most common: ill-defined border (90%), irregularly distributed pigmentation (84%), maximum diameter greater than 5.0 mm (72%), erythema (64%), and accentuated skin markings (63%). Increasing darkness and confluence of pigmentation in these dysplastic melanocytic nevi correlated with increasing severity of dysplasia. We conclude that careful clinical examination of individual melanocytic nevi will separate severe dysplasia with or without in situ melanoma from low-grade (mild or moderate) dysplasia in a high percentage of nevi from patients with the dysplastic nevus syndrome. Clinical examination will yield a diagnosis of dysplasia in approximately 75% of nevi from such patients in whom histologic evidence of dysplasia is present. Clinical examination constitutes a practical and sufficiently reliable method for the assessment of melanocytic nevi in patients with the dysplastic nevus syndrome.
Article
Malignant melanoma is the deadliest form of all skin cancers. Approximately 32,000 new cases of malignant melanoma were diagnosed in 1991 in the United States, with approximately 80% of patients expected to survive five years [1]. Fortunately, if detected early, even malignant melanoma may be treated successfully. Thus, in recent years, there has been rising interest in the automated detection and diagnosis of skin cancer, particularly malignant melanoma [2]. In this paper, we present a novel neural network approach for the automated separation of melanoma from three benign categories of tumors which exhibit melanoma-like characteristics. Our approach uses discriminant features, based on tumor shape and relative tumor color, that are supplied to an artificial neural network for classification of tumor images as malignant or benign. With this approach, for reasonably balanced training/testing sets, we are able to obtain above 80% correct classification of the malignant and benign tumors on real skin tumor images.
Article
A new system of impedance measurement over a frequency range of 0 to 200 kHz was developed by a three-electrode method. In this study, the electrical impedances of various tumors were measured in vivo in 54 patients with breast disease (31 breast cancers, 13 fibroadenomas, and 10 fibrocystic diseases) and 57 patients with pulmonary disease (44 lung cancers, 5 metastatic pulmonary tumors, 4 pulmonary tuberculoses, and 4 organized pneumonias). On the basis of those impedance measurements and the equivalent circuits in vivo, we calculated the extracellular resistance (Re), intracellular fluid resistance (Ri), and cell membrane capacitance (Cm) in tissues, all of which were compared among the various diseases. It was found that Re and Ri were significantly higher in breast cancers than in benign tumors and normal breast tissues and that Cm was significantly lower in breast cancers than in other tissues. On the other hand, Re and Ri were significantly higher, and Cm was significantly lower, in normal lung tissues than in pulmonary masses. Re and Ri were significantly higher, and Cm was significantly lower, in malignant tumors than in organized pneumonias. The results showed that these parameters (Re, Ri, and Cm) exhibit significant differences among various tissues and tumors, suggesting possible applications in tumor diagnosis.
Article
We have explored the use of measurements of electrical impedance to discriminate between the effects of different irritant substances upon the skin, and have studied the relationships between impedance and histopathological change. Three compounds with different chemical profiles were tested on volunteers: sodium lauryl sulphate, benzalkonium chloride and nonanoic acid. The concentrations selected were such that each irritant produced responses of a similar order, as judged by visual scores. The magnitude and phase of electrical impedance were measured and, for comparison, also the transepidermal water loss. Four physically distinct aspects (indices) were devised from the impedance data, and the values obtained were statistically analysed. The three irritants produced different effects, giving distinctive impedance patterns. These were also found to be reflected by three different types of histopathological skin response. Our results suggest that the indices can be used to classify irritant contact reactions, which it is difficult or impossible to achieve by other non-invasive techniques.
Article
The impedivity of six groups of breast tissue is measured between 0.488 kHz and 1 MHz using a hand-held probe, ensuring a constant geometry factor, and a microcomputer-controlled impedance spectroscopy system. 120 spectra are collected in excised tissue samples from 64 patients undergoing breast surgery. Each spectrum consists of 12 frequency points. The mean m, the standard deviation s, and the 'reduced standard error' (epsilon = s/(m N)) of the magnitude and the phase angle of the impedivity are calculated at each frequency for all groups of tissues. The variability at low frequency (f < 10 kHz) is attributed to the dispersion in measurement errors. This contributed to the choice of 32 KHz as the lower limit of measurement frequency in constructed electrical impedance tomograph. The collected data also show that frequencies larger than 1 MHz are needed for the bio-electrical characterisation of breast tissue. In the frequency range used in electrical impedance tomography the reduced standard error of impedivity in breast tissue is about 0.1 or less. The lowest dispersions are observed in the adipose tissue, carcinoma and fibro-adenoma.
Article
Previously, we have explored the use of measurements of electrical impedance and devised 4 physically distinct indices named magnitude index (MIX), phase index, real part index and imaginary part index (IMIX) from the impedance data. Our results indicated that these indices could characterize contact reactions. The goal of the present study was to use the electrical impedance method for the preoperative assessment of nodular basal cell carcinoma (BCC). We included 11 patients with a total of 12 nodular BCC, diagnosed clinically and histologically. The noninvasive measurements were performed by transepidermal water loss (TEWL) and electrical impedance. For reference, normal looking contralateral or ipsilateral skin was used. Compared to controls, the mean TEWL of BCC was increased, but this finding was not statistically significant. The electrical impedance measurements of BCC tissue revealed statistically significant changes of the impedance indices MIX and IMIX (p </=0.001). The results suggest that the measurement of electrical impedance might become useful for investigations of BCC.
Article
To use a digital dermoscopy analyzer with a series of "borderline" pigmentary skin lesions (ie, clinically atypical nevi and early melanoma) to find correlation between the studied variables and to determine their discriminating power with respect to histological diagnosis. A total of 147 pigmentary skin lesions were histologically examined by 3 experienced dermatopathologists and identified as nevi (n = 90) and melanomas (n = 57). The system evaluated 36 variables to be studied as possible discriminant variables, grouped into 4 categories: geometries, colors, textures, and islands of color. University medical department. A sample of patients with excised pigmentary skin lesions (nevi and melanomas). Sensitivity, specificity, and accuracy of the model for evaluating "borderline" pigmentary skin lesions. After multivariate stepwise discriminant analysis, only 13 variables were selected to compute the canonical discriminant function. The present method made it possible to determine which objective variables are important for distinguishing atypical benign pigmentary skin lesions and early melanoma.
Article
It has long been established that cancer cells exhibit altered local dielectric properties compared with normal cells. Consequently, different electrical conductivity and capacitance are measurable in malignant vs normal tissues. In this study we evaluated the reliability of electrical impedance scanning (EIS), a new technology, for the classification of suspicious lesions: differentiating benign from malignant, and as a primary means of detection of breast cancer. Fifty-two women with 58 sonographically and/or mammographically suspicious findings were examined using electrical impedance scanning. Two different examination modes of TransScan TS2000 (Siemens, Erlangen, Germany), the standard-resolution mode for a routine overview examination, and the targeted high-resolution mode for a local examination of the suspicious lesion were used. All patients were additionally imaged by MR mammography (MRM) and underwent core-biopsy and/or surgical treatment after the EIS examination. With respect to the histopathological findings (29 malignant and 29 benign lesions) 27 of 29 (93.1%) malignant lesions were correctly identified using the high-resolution mode of EIS, whereas 19 of 29 (65.5%) benign lesions were correctly identified as benign (10 of 29 benign lesions showed as false-positive findings). Negative and positive predictive values of 90.5 and 73.0% were observed, respectively. Using the standard-resolution mode 22 of 29 malignancies were correctly detected (sensitivity 75.9%), whereas 22 of 29 were correctly identified as benign (specificity 72.4%). Electrical impedance scanning appears to be a promising new technology providing a relatively high sensitivity for the verification of suspicious mammographic and/or sonographic lesions especially using the high-resolution mode for local examinations. Artifacts, such as signals from superficial skin lesions, poor contact, and air bubbles, are currently a limitation.
Article
Differentiation of melanoma from melanocytic nevi is difficult even for skin cancer specialists. This motivates interest in computer-assisted analysis of lesion images. Our purpose was to offer fully automatic differentiation of melanoma from dysplastic and other melanocytic nevi through multispectral digital dermoscopy. At 4 clinical centers, images were taken of pigmented lesions suspected of being melanoma before biopsy. Ten gray-level (MelaFind) images of each lesion were acquired, each in a different portion of the visible and near-infrared spectrum. The images of 63 melanomas (33 invasive, 30 in situ) and 183 melanocytic nevi (of which 111 were dysplastic) were processed automatically through a computer expert system to separate melanomas from nevi. The expert system used either a linear or a nonlinear classifier. The "gold standard" for training and testing these classifiers was concordant diagnosis by two dermatopathologists. On resubstitution, 100% sensitivity was achieved at 85% specificity with a 13-parameter linear classifier and 100%/73% with a 12-parameter nonlinear classifier. Under leave-one-out cross-validation, the linear classifier gave 100%/84% (sensitivity/specificity), whereas the nonlinear classifier gave 95%/68%. Infrared image features were significant, as were features based on wavelet analysis. Automatic differentiation of invasive and in situ melanomas from melanocytic nevi is feasible, through multispectral digital dermoscopy.
Article
Various modalities are used as an adjunct to mammography for differentiation of potentially suspicious breast lesions. Electrical impedance scanning (EIS) is a new technique based upon the principle that cancer cells exhibit altered local dielectric properties and thus show measurably higher conductivity values. The accuracy of differentiation of benign and malignant breast lesions was evaluated to determine whether EIS duplicates or supplements the results obtainable from ultrasound (US) or magnetic resonance imaging (MRI). One hundred mammographically suspicious lesions were examined using US, MRI and EIS. Definitive histology was acquired through either lesion biopsy or surgical excision. Fifty of 62 malignant lesions were correctly identified using EIS (81% overall sensitivity), 24/38 benign lesions were correctly identified as benign (63% specificity). Negative predictive value and positive predictive value of 67 and 78% were observed, respectively. kappa-factor evaluation revealed a value of 0.82 between MRI and EIS and 0.62 between US and EIS. EIS may be a valuable adjunct for differentiation of suspicious mammographic lesions. Based upon the calculated kappa-factor, EIS results supplement US examinations. Artifacts (superficial skin lesions, poor contact, air bubbles) currently result in the high false-positive rate of EIS.
Article
Risk stratification of pigmented lesions during melanoma screening is a method of classifying lesions into groups based on their relative risk of being melanoma. Risk stratification accepts the fact that clinical examination with and without ELM is not perfect but uses potential ELM clues to early melanoma to increase the sensitivity of screening. Risk stratification permits the use of all available a priori clinical information and the physician's judgement in making a final management decision for each lesion and for each patient. Risk stratification using ELM is based on two primary concepts: (1) a pigment network suggests a lesion is melanocytic and (2) melanoma causes the network to develop heterogeneous (i.e., irregular) and eccentric (i.e., not centered) pigmentation. In applying ELM risk stratification to melanoma screening the physician follows these four steps: 1. Inspect each lesion carefully for a pigment network. 2. If a pigment network is seen, group lesions by their relative degrees of heterogeneity and eccentricity of the pigment network. 3. If a network is not seen, look for typical patterns of benign lesions and melanoma mimickers. 4. Use the resulting clinical risk class to guide management using all available clinical information combined with clinical judgment.
Article
The aim of this study was to quantify the clinical value of using electrical impedance scanning (EIS) as an adjunct to other diagnostic techniques in order to identify cancerous tissue based upon its inherent altered local dielectric properties. 210 consecutive women with 240 sonographically and/or mammographically suspicious findings were examined using EIS. All lesions were histologically-proven. 86/103 malignant and 91/137 benign lesions were correctly identified using EIS (87.8% sensitivity, 66.4% specificity). NPV and PPV of 84.3% and 65.2% were observed, respectively. Excluding cases as defined by a priori criteria, i.e. lesions located deeper than 35 mm, lesions larger than 35 mm, and retroareolar lesions, a sensitivity of 85.5% was observed, and for invasive cancers, 91.7%. The detection rate for ductal carcinoma in situ (DCIS) was poor (57.1%, n=14). By adding EIS to mammography and ultrasound, the sensitivity rose from 86.4 to 95.1%, whereas the accuracy decreased from 82.3 to 75.7%. EIS appears to be of interest as an adjunct to breast diagnostic techniques, performing with a reasonable sensitivity. Further investigations on histomorphological characteristics and the reasons for false-negative findings are essential to gain further knowledge about the bioelectricity of breast lesions, and prove the value of this new technology.
Knowledge about diagnostic procedures in melanoma has increased rapidly within the past few years. These new techniques include epiluminescence microscopy and computerized image analysis of pigmented skin lesions, as well as the identification of single tumor cells in normal tissue, such as sentinal lymph node and peripheral blood by molecular approaches. The introduction of polymerase-chain reaction based methods can be regarded as a prototype of this dramatic development that opens up the possibility of clinical use in patients, and of influencing treatment strategies. While early melanoma is highly curable by surgical means, the prognosis of patients with metastatic disease remains poor. A flurry of new treatment strategies are currently in clinical development. These include test-directed chemotherapy, biologic therapy, vaccine therapy, as well as gene therapy. All different therapeutic strategies have to take into account immense resistance and escape mechanisms of malignant melanoma cells, that potentially limit the effectiveness of new treatment concepts.
Article
To evaluate the potential of targeted electrical impedance scanning (EIS) for classifying suspicious breast lesions. EIS was performed in full knowledge of mammographic findings and findings of clinical breast examination. One hundred seventeen patients with a total of 129 breast lesions were examined with EIS before breast biopsy (surgical excision or vacuum core biopsy). Diagnostic indexes of targeted EIS were calculated depending on major lesion characteristics. Capacitance and conductivity of all positive spots (S) and the surrounding normal breast tissue (NBT) were quantified using ROI measurements. The ratio S/NBT was calculated to compare true positive (n = 44) and false positive (n = 18) spots. With respect to histology, of the 129 lesions 71 were malignant and 58 lesions were benign. Overall sensitivity of targeted EIS was 62%, specificity 69%, PPV 71%, and NPV 60%. Sensitivity of EIS varied depending on the tumor size, which was between 48% (> 20 mm) and 71% (11-20 mm). Highest specificity (86%) was observed for large lesions (> 20 mm); however, the NPV was only 35% for lesions of that size. NPV was higher for nonpalpable lesions (74%) and clusters of microcalcifications (85.7%) compared with palpable lesions (39%) and solid lesions (44%). There was no statistical difference of S/NBT ratio neither for conductivity nor capacitance of true and false positive spots. Compared with true positive spots a trend of a higher conductivity ratio at 100 Hz and 200 Hz was seen for false positive spots. EIS showed mediocre overall diagnostic accuracy for classifying suspicious breast lesions. Quantitative analysis of positive EIS findings did not help to differentiate between false and true positive spots.
Article
The aim of this study is to explore the various diagnostic techniques for melanoma and assess their usefulness in the clinical practice of nurse practitioners. After a systematic review of the literature, 55 articles were closely reviewed, and from these, 26 studies were selected. These were original studies in English that examined diagnostic techniques that would improve accuracy for melanoma detection with a formal methods and results section. Six general categories dealing with diagnostic techniques for melanoma were found in the literature. These were naked-eye clinical examination alone, clinical examination with the aid of total-body photographs, epiluminescence microscopy (ELM), digital ELM, computer-assisted techniques, and teledermatology. Because of the research citing the poor diagnostic accuracy (DA) of nondermatologists, increased DA with dermatologists experienced in ELM techniques, and the importance of early melanoma diagnosis, the recommendation is to refer patients with suspicious pigmented skin lesions to experienced dermatologists, preferably those who use ELM or digital ELM.
Article
The clinical use of dermoscopy has uncovered a new and fascinating morphological dimension of pigmented skin lesions. Dermoscopy is a non-invasive diagnostic technique that links clinical dermatology and dermatopathology by enabling the visualisation of morphological features not seen by the naked eye. Close examination of pigmented skin lesions in this way increases the effectiveness of clinical diagnostic tools by providing new morphological criteria for distinguishing melanoma from other melanocytic and non-melanocytic pigmented skin lesions. In the past, dermoscopy has been known by various names, including skin surface microscopy, epiluminescence microscopy, incident light microscopy, dermatoscopy, and videodermatoscopy. However, the term 'dermoscopy', first used by Friedman and colleagues in 1991, is the most widely used.
The new morphological information provided by epiluminescence microscopy (ELM) requires a fresh approach to the analysis of pigmented lesions. It necessitates a learning process that pertains to the recognition of hitherto unknown morphological features and is based on the discrimination of these features and their combination into two different patterns. ELM has been shown to improve the sensitivity and specificity of the diagnosis of melanoma and other pigmented lesions by 25-30%. Digitized ELM (DELM) provides an unlimited capacity for data storage and retrieval. It is a computerized imaging method, objective and noninvasive; it provides objective evidence of lesional changes on follow-up; documents growth and any changes in the structure and shape of lesions; and thus helps in decisions on whether to excise them or not. It provides for quality control by means of the aforementioned documentation, which may also serve as back-up in the case of medico-legal problems. In addition, the spectrum is widened by the dimension of teledermatology and cybernet computer-assisted diagnosis, which holds great promise for the future. ELM and DELM are thus the most important single development of the past three decades in the early diagnosis of melanoma.
Article
A new postprocessing algorithm was developed for the diagnosis of breast cancer using electrical impedance scanning. This algorithm automatically recognizes bright focal spots in the conductivity map of the breast. Moreover, this algorithm discriminates between malignant and benign/normal tissues using two main predictors: phase at 5 kHz and crossover frequency, the frequency at which the imaginary part of the admittance is at its maximum. The thresholds for these predictors were adjusted using a learning group consisting of 83 carcinomas and 378 benign cases. In addition, the algorithm was verified on an independent test group including 87 carcinomas, 153 benign cases and 356 asymptomatic cases. Biopsy was used as gold standard for determining pathology in the symptomatic cases. A sensitivity of 84% and a specificity of 52% were obtained for the test group.
Risk stratification. A practical approach to using epiluminescence microscopy/dermoscopy in melanoma screening Dielectric properties of tissues and biological materials: a critical review
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Fuchsjaeger M, Diebold T, Szabo B, Malich A, Kaiser W, Bone B, Vogel TJ, Helbich T. Adjunctive use of electrical impedance scanning (EIS) new software algorithm to differentiate breast lesions in comparison to histopathology: European multicentre study. ECR Vienna 2002: Presentation B-0649.
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Correlation of impedance response patterns to histological findings in irritant skin reactions induced by various surfactants
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