Electrical Impedance Scanning for the Early Detection of Breast Cancer in Young Women: Preliminary Results of a Multicenter Prospective Clinical Trial

The Use of Virtual Tissue Constructs That Include Morphological Variability to Assess the Potential of Electrical Impedance Spectroscopy to Differentiate between Thyroid and Parathyroid Tissues during Surgery

Electrical impedance spectroscopy (EIS) has been proposed as a promising noninvasive method to differentiate healthy thyroid from parathyroid tissues during thyroidectomy. However, previously reported similarities in the in vivo measured spectra of these tissues during a pilot study suggest that this separation may not be straightforward. We utilise computational modelling as a method to elucidate the distinguishing characteristics in the EIS signal and explore the features of the tissue that contribute to the observed electrical behaviour. Firstly, multiscale finite element models (or 'virtual tissue constructs') of thyroid and parathyroid tissues were developed and verified against in vivo tissue measurements. A global sensitivity analysis was performed to investigate the impact of physiological micro-, meso- and macroscale tissue morphological features of both tissue types on the computed macroscale EIS spectra and explore the separability of the two tissue types. Our results suggest that the presence of a surface fascia layer could obstruct tissue differentiation, but an analysis of the separability of simulated spectra without the surface fascia layer suggests that differentiation of the two tissue types should be possible if this layer is completely removed by the surgeon. Comprehensive in vivo measurements are required to fully determine the potential for EIS as a method in distinguishing between thyroid and parathyroid tissues.

Multiscale Model Development for Electrical Properties of Thyroid and Parathyroid Tissues

Goal: Electrical impedance spectroscopy (EIS) has been suggested as a possible technique to differentiate between thyroid and parathyroid tissue during surgery. This study aims to explore this potential using computational models to simulate the impedance spectra of these tissues, and examine how they are influenced by specific differences in tissue composition and morphology. Materials and methods: Finite element models of thyroid and parathyroid tissues at multiple scales were created, and simulated spectra were compared to existing data collected using ZedScanTM probe during surgery. Geometrical and material properties were varied in a local sensitivity study to assess their relative influence. Results: Both simulated and measured EIS parathyroid spectra show a higher [Formula: see text] dispersion frequency relative to thyroid. However, impedances exhibit overlap at frequencies below 100 kHz. A computational sensitivity study identified uncertainties in extracellular space dimensions, and properties of colloid and fascia compartments as having a significant effect on simulated impedance spectra characteristics. Conclusions: We have demonstrated the utility of our multiscale model in simulating impedance spectra and providing insight into their sensitivity to variations in tissue features. Our results suggest that distinguishing between the thyroid and parathyroid spectra is challenging, but could be improved by constraining the properties of colloid and fascia through further computational or experimental research.

Advanced Enhancement Techniques for Breast Cancer Classification in Mammographic Images

Background:

Breast cancer is one of the most significant health problems in the world. Early diagnosis of breast cancer is very important for treatment. Image enhancement techniques have been used to improve the captured images for quick and accurate diagnosis. These techniques include median filtering, edge enhancement, dilation, erosion, and contrast-limited adaptive histogram equalization. Although these techniques have been used in many studies, their results have not reached optimum values based on image properties and the methods used for feature extraction and classification.

Methods:

In this study, enhancement techniques were implemented to guarantee the best image enhancement. They were applied to 319 images collected from the Mammographic Image Analysis Society (MIAS) database. The Gabor filter and local binary pattern were used as feature extraction methods together with support vector machine (SVM), linear discriminant analysis (LDA), and nearest neighbor (KNN) classifiers.

Results:

The experimental work indicates that by merging the features of the Gabor filter and local binary pattern, the results were 97.8%, 100%, and 94.6% for normal/abnormal and 85.1%, 88.7%, and 81.9% for benign/malignant using the SVM, LDA, and KNN classifiers, respectively.

Conclusion:

The best results were obtained by combining the features of the two tested strategies and using LDA as a classifier.

Electrical Impedance Analysis for Lung Cancer: A Prospective, Multicenter, Blind Validation Study

Hypothesis

Patients with cancer have different impedances or conductances than patients with benign normal tissue; thus, we can apply electrical impedance analysis (EIA) to identify patients with cancer.

Method

To evaluate EIA’s efficacy and safety profile in diagnosing pulmonary lesions, we conducted a prospective, multicenter study among patients with pulmonary lesions recruited from 4 clinical centers (Zhongshan Hospital Ethics Committee, Approval No. 2015-16R and 2017-035(3). They underwent EIA to obtain an Algorithm Composite Score or ‘Prolung Index,’ PI. The classification threshold of 29 was first tested in an analytical validation set of 144 patients and independently validated in a clinical validation set of 418 patients. The subject’s final diagnosis depended on histology and a 2-year follow-up.

Results

In total, 418 patients completed the entire protocol for clinical validation, with 186 true positives, 145 true negatives, 52 false positives, and 35 false negatives. The sensitivity, specificity, and diagnostic yield were 84% (95% CI 79.3%-89.0%), 74% (95% CI 67.4%-79.8%), and 79% (95%CI 75.3%-83.1%), respectively, and did not differ according to age, sex, smoking history, body mass index, or lesion types. The sensitivity of small lesions was comparable to that of large lesions (p = 0.13). Four hundred eighty-four patients who underwent the analysis received a safety evaluation. No adverse events were considered to be related to the test.

Conclusion

Electrical impedance analysis is a safe and efficient tool for risk stratification of pulmonary lesions, especially for patients with a suspicious lung lesion.

Adjunctive Diagnostic Methods for Skin Cancer Detection: A Review of Electrical Impedance-Based Techniques

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. © 2022 Bioelectromagnetics Society.

Intra-radiological pathology-calibrated Electrical Impedance Spectroscopy in the evaluation of excision-required breast lesions

PURPOSE

Evaluating a real-time complementary bioelectrical diagnostic device based on Electrical Impedance Spectroscopy(EIS) for improving breast imaging-reporting and data system (BIRADS) scoring accuracy, especially in high-risk or borderline breast diseases. The primary purpose is to characterize breast tumors based on their dielectric properties. Early detection of high-risk lesions and increasing the accuracy of tumor sampling and pathological diagnosis are secondary objectives of the study.

METHODS

The tumor detection probe (TDP) was first applied to the mouse model for electrical safety evaluations by electrical current measurement, then to 138 human palpable breast lesions undergo CNB, VAB, or FNA with the surgeon's requests. Impedance phase slope(IPS) in frequency ranges of 100 kHz to 500 kHz and impedance magnitude in f = 1kHz were extracted as the classification parameters. Consistency of radiological and pathological declarations for the excisional recommendation was then compared with the IPS values.

RESULTS

Considering pathological results as the gold standard, meaningful correlations between IPS and pathophysiological status of lesions recommended for excision (such as atypical ductal hyperplasia, papillary lesions, complex sclerosing adenosis, and fibroadenoma, etc.) were observed (p<0.0001). These pathophysiological properties may include cells size, membrane permeability, packing density, adenosis, cytoplasm structure, etc. Benign breast lesions showed IPS values greater than zero, while high-risk proliferative, precancerous, or cancerous lesions had negative IPS values. Statistical analysis showed 95% sensitivity with Area Under the Curve(AUC) equal to 0.92.

CONCLUSION

Borderline breast diseases and high-risk lesions that should be excised according to standard guidelines can be diagnosed with TDP before any sampling process. It is a precious outcome for high-risk lesions that are radiologically underestimated to BI-RADS3, specifically in younger patients with dense breast masses, challenging in mammographic and sonographic evaluations. Also, the lowest IPS value detects the most pathologic portions of the tumor for increasing sampling accuracy in large tumors.

SIGNIFICANCE

Precise detection of high-risk breast masses, which may be declared BI-RADS3 instead of BI-RADS4a. This article is protected by copyright. All rights reserved.

[Connected bras for breast cancer detection in 2021: Analysis and perspectives]

OBJECTIVES

Breast cancer is the leading cancer in women worldwide with about 2 million new cases and 685,000 deaths each year. Mammography is the most widely used screening and diagnostic method. Currently, digital technologies advances facilitate the development of connected and portable devices. To overcome some of the disadvantages of mammography (breast compression, difficulty in analyzing dense breasts, radiation, limited accessibility in some countries, etc.), portable devices, conventionally known as connected bras (CB), have been created to offer an alternative method to mammography. The objective of our review was to list all the published CBs in order to know their main characteristics, their potential indications and their possible limitations.

METHOD

A bibliographical search in the PUBMED database selecting only articles written in French or English, between 2011 and 2020, found 7 CBs under development.

RESULTS

These CBs use thermal, ultrasonic and impedance sensors. Their advantages are an absence of irradiation, an absence of breast compression and a flexibility of use (outside an X-ray cabinet). Mammary gland analysis times vary, depending on the device, between 30min and 24h. They are all connected to data transmission systems and models that analyze the results.

DISCUSSION AND CONCLUSION

These CBs are mostly still undergoing clinical validation (only [iTBra] has been evaluated in a clinical trial) and require evaluation steps that will eventually allow their future use for breast cancer detection in high-risk women, particularly in women with dense breasts and in women between screening waves.

Monofrequency electrical impedance mammography (EIM) diagnostic system in breast cancer screening

BACKGROUND

Some evidence has shown that malignant breast tumours have lower electrical impedance than surrounding normal tissues. Electrical impedance could be used as an indicator for breast cancer detection. The purpose of our study was to analyse the sensitivity and specificity of electrical impedance mammography (EIM) and its implementation for the differential diagnosis of pathological lesions of the breast, either alone or in combination with mammography/ultrasound, in 1200 women between 25 and 70 years old.

METHODS

This study is a prospective, cross-sectional epidemiological observational study of serial screening. The women were invited to participate and signed a consent letter. Impedance imaging of the mammary gland was evaluated with the computerized mammography equipment of MEIK electroimpedance v.5.6. (0.5 mA, 50 kHz), developed and manufactured by PKF SIM-Technika®. The successful identification of breast cancer along with the sensitivity, specificity, and positive and negative predictive values of EIM were determined as follows: % sensitivity; % specificity; % positive predictive value (PPV); and % negative predictive value (NPV).

RESULTS

EIM had a sensitivity of 85% and a specificity of 96%; the positive predictive value was 12%, and the negative predictive value was 99%. Seven cases were biopsy confirmed cancers. Significant correlations between the electrical conductivity index and body mass index (BMI) (p = 0.04) and patient age were observed (p = 0.01). We also observed that the average conductivity distribution increased according to age group (p = 0.001). We used the chi-squared test to assess the interactions between percent density and BMI (normal < 25 kg/m2 (n = 310), overweight 25-29.9 kg/m2 (n = 418) and obese ≥30 (n = 437)) (p <  0.05). The patients with a diagnosis of mammary carcinoma had a BMI of 35.51 kg/m2.

CONCLUSIONS

Our results demonstrate that the use of monofrequency electrical impedance mammography (EIM) in the detection of breast cancer had a sensitivity and specificity of 85 and 96%, respectively. These findings may support future research in the early detection of breast cancer. EIM is a non-radiation method that may also be used as a screening method for young women with dense breasts and a high risk of developing breast cancer.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Evaluation on Phantoms of the Feasibility of a Smart Bra to Detect Breast Cancer in Young Adults

Breast cancer is the most common cancer observed in women. Although mammography is a recognized method, it remains ionizing and cannot be used routinely or in young adults, leaving up to two years between two diagnoses. Prior to validation on human subjects, this study aims to validate on phantoms the feasibility of quantifying breast density and detecting breast cancer tumors using a smart bra in young women. Six phantoms with various densities and seven phantoms with various volumes of modelized tumor were prepared and measured with a smart bra, including an electrophysiological module. There was a significant difference between the "healthy phantoms" and the "tumor phantoms" with P(Student) = 0.008 (Shapiro-Wilk p = 0.846, samples follow a normal distribution; Fisher variance test, p = 0.287). In addition, this study seems to indicate the possibility of discriminating various types of tumorous and healthy breast tissue using a smart bra, in high density breast. However, a new study on a large sample of human subjects will be required to generate new models, including resistive, capacitive, and other sensor parameters versus reference data collected from imaging.

Noninvasive pulmonary nodule characterization using transcutaneous bioconductance: Preliminary results of an observational study

We sought to assess the use of an electro pulmonary nodule (EPN) scanner (FreshMedx, Salt Lake City, UT) in the noninvasive characterization of pulmonary nodules using transcutaneous bioconductance.Monocentric prospective study including patients with a pulmonary nodule identified on a chest computed tomography scan. Study protocol approved by the institutional review board and written consent was obtained for every patient. 32 patients (12 females and 20 males), average age 65 years, and average lesion size 33.1 mm (range: 9-123 mm). Data collection by a trained physician, 62 skin surface measurements on the chest, arms, and hands bilaterally. Results were anonymized and mailed to a central data center for analysis and compared to histopathology.Pathology results obtained by percutaneous biopsy (n = 14), surgical biopsy (n = 1), or surgical resection (n = 17) showed 29 malignant lesions (adenocarcinoma n = 21, squamous cell carcinoma n = 5, typical carcinoid n = 1, metastasis n = 2), and 3 benign lesions (necrotic granuloma n = 1, no malignant cells on biopsy n = 2). EPN scanner results had a specificity of 66.67% (95% confidence interval [CI] 0.09-0.99), sensitivity 72.41% (95% CI 0.53-0.87), positive predictive value 95.45% (95% CI 0.81-0.99), and a negative predictive value 20.00% (95% CI 0.08-0.40).This pilot study showed a high positive predictive value of the EPN scanner, allowing aggressive management of lung nodules characterized as malignant. The low negative predictive value warrants further investigation of nodules that are characterized as benign.

Low-cost multifrequency electrical impedance-based system (MFEIBS) for clinical imaging: design and performance evaluation

Electrical impedance tomography (EIT) is an upcoming and capable imaging modality used for clinical imaging. It is non-invasive, non-ionising and an inexpensive technique. This paper explains the designing and the analysis of a low-cost multifrequency electrical impedance-based system (MFEIBS) having a flexible mechanism of interfacing up to 32 electrodes, suitable for 1 kHz-2 MHz. Various indicators to check the performance of the EIT system were evaluated and presented here. The performance of VCO and VCCS was measured up to 2 MHz. SNR was measured with saline phantom and its mean value is 74 dB for the complete bandwidth. Different combinations of resistors and capacitors were used to find the accuracy of the system, and relative error was less than 0.55% for the entire range. CMRR of the system was calculated and it was found to be maximum 85 dB at 1 kHz frequency. A 16-electrode circular plastic phantom having a diameter of 18 cm was established and connected with a simple MFEIBS. Obtained surface potential was applied to the computer used for image formation using NI USB-6259, 16-bit, 1.25 MS/s M Series High-speed DAQ. Images reconstructed using the system presented in this paper was generated from a 16-electrode plastic phantom filled with NaCl up to 1.2 cm height.

Electrical Impedance Myography and Its Applications in Neuromuscular Disorders

Electrical impedance myography (EIM) refers to the specific application of electrical bioimpedance techniques for the assessment of neuromuscular disorders. In EIM, a weak, high-frequency electrical current is applied to a muscle or muscle group of interest and the resulting voltages measured. Among its advantages, the technique can be used noninvasively across a variety of disorders and requires limited subject cooperation and evaluator training to obtain accurate and repeatable data. Studies in both animals and human subjects support its potential utility as a primary diagnostic tool, as well as a biomarker for clinical trial or individual patient use. This review begins by providing an overview of the current state and technological advances in electrical impedance myography and its specific application to the study of muscle. We then provide a summary of the clinical and preclinical applications of EIM for neuromuscular conditions, and conclude with an evaluation of ongoing research efforts and future developments.

Nerve localization techniques for peripheral nerve block and possible future directions

BACKGROUND

Ultrasound guidance is now a standard nerve localization technique for peripheral nerve block (PNB). Ultrasonography allows simultaneous visualization of the target nerve, needle, local anesthetic injectate, and surrounding anatomical structures. Accurate deposition of local anesthetic next to the nerve is essential to the success of the nerve block procedure. Due to limitations in the visibility of both needle tip and nerve surface, the precise relationship between needle tip and target nerve is unknown at the moment of injection. Importantly, nerve injury may result both from an inappropriately placed needle tip and inappropriately placed local anesthetic. The relationship between the block needle tip and target nerve is of paramount importance to the safe conduct of peripheral nerve block.

METHODS

This review summarizes the evolution of nerve localization in regional anesthesia, characterizes a problem faced by clinicians in performing ultrasound-guided nerve block, and explores the potential technological solutions to this problem.

RESULTS

To date, technology newly applied to PNB includes real-time 3D imaging, multi-planar magnetic needle guidance, and in-line injection pressure monitoring. This review postulates that optical reflectance spectroscopy and bioimpedance may allow for accurate identification of the relationship between needle tip and target nerve, currently a high priority deficit in PNB techniques.

CONCLUSIONS

Until it is known how best to define the relationship between needle and nerve at the moment of injection, some common sense principles are suggested.

Bioimpedance Detection of Oral Lichen Planus Used as Preneoplastic Model

INTRODUCTION

Bioimpedance is a measure of the electrical properties of biological tissues. In the last two decades bioimpedance has been successfully introduced in clinical diagnosis of cancer. It has been demonstrated that tumoral tissues often show lower bioimpedance values than healthy tissues. The aim of this work is to assess the bioimpedentiometric differences between healthy and Oral Lichen Planus (OLP) affected oral mucosa, taking attention to the erosive form which may represent a potential pre-cancerous condition.

METHODS

52 patients affected by OLP were recruited for bioimpedance examination of oral mucosa. Four electrical properties, resistance (R), reactance (Xc), phase angle (θ) and impedance (Z) of the tongue and of the intraoral mucosa, were measured.

RESULTS

We observed a significant increase of Z and a significant decrease of θ values in correspondence of OLP lesions compared to healthy oral mucosa, and a marked decrease of Z values in correspondence of erosive OLP lesions.

CONCLUSIONS

These results provide evidence of the usefulness of bioimpedance assay for the characterization of healthy and clinically OLP affected mucosa. Bioimpedance is a valid aid in the early detection and clinical monitoring of the suspicious lesions which could lead to a potentially malignant evolution. The present research article is a valuable addition to the scientific literature of cancer prevention, and our findings can be considered extremely encouraging as they represent the initial step for a more wide clinical study for better define the different cut-off values in the different precancerous conditions occurring in the oral mucosa.

Optical imaging for breast cancer prescreening

Breast cancer prescreening is carried out prior to the gold standard screening using X-ray mammography and/or ultrasound. Prescreening is typically carried out using clinical breast examination (CBE) or self-breast examinations (SBEs). Since CBE and SBE have high false-positive rates, there is a need for a low-cost, noninvasive, non-radiative, and portable imaging modality that can be used as a prescreening tool to complement CBE/SBE. This review focuses on the various hand-held optical imaging devices that have been developed and applied toward early-stage breast cancer detection or as a prescreening tool via phantom, in vivo, and breast cancer imaging studies. Apart from the various optical devices developed by different research groups, a wide-field fiber-free near-infrared optical scanner has been developed for transillumination-based breast imaging in our Optical Imaging Laboratory. Preliminary in vivo studies on normal breast tissues, with absorption-contrasted targets placed in the intramammary fold, detected targets as deep as 8.8 cm. Future work involves in vivo imaging studies on breast cancer subjects and comparison with the gold standard X-ray mammography approach.

Magnetic-resonance-based electrical properties tomography: a review

Frequency-dependent electrical properties (EPs; conductivity and permittivity) of biological tissues provide important diagnostic information (e.g., tumor characterization), and also play an important role in quantifying radiofrequency (RF) coil induced specific absorption rate (SAR), which is a major safety concern in high- and ultrahigh-field magnetic resonance imaging (MRI) applications. Cross-sectional imaging of EPs has been pursued for decades. Recently introduced electrical properties tomography (EPT) approaches utilize the measurable RF magnetic field induced by the RF coil in an MRI system to quantitatively reconstruct the EP distribution in vivo and noninvasively with a spatial resolution of a few millimeters or less. This paper reviews the EPT approach from its basic theory in electromagnetism to the state-of-the-art research outcomes. Emphasizing on the imaging reconstruction methods rather than experimentation techniques, we review the developed imaging algorithms, validation results in physical phantoms and biological tissues, as well as their applications in in vivo tumor detection and subject-specific SAR prediction. Challenges for future research are also discussed.

Electrical impedance spectroscopy as electrical biopsy for monitoring radiation sequelae of intestine in rats

Electrical impedance is one of the most frequently used parameters for characterizing material properties. The resistive and capacitive characteristics of tissue may be revealed by electrical impedance spectroscopy (EIS) as electrical biopsy. This technique could be used to monitor the sequelae after irradiation. In this study, rat intestinal tissues after irradiation were assessed by EIS system based on commercially available integrated circuits. The EIS results were fitted to a resistor-capacitor circuit model to determine the electrical properties of the tissue. The variations in the electrical characteristics of the tissue were compared to radiation injury score (RIS) by morphological and histological findings. The electrical properties, based on receiver operation curve (ROC) analysis, strongly reflected the histological changes with excellent diagnosis performance. The results of this study suggest that electrical biopsy reflects histological changes after irradiation. This approach may significantly augment the evaluation of tissue after irradiation. It could provide rapid results for decision making in monitoring radiation sequelae prospectively.

The correlation between extracellular resistance by electrical biopsy and the ratio of optical low staining area in irradiated intestinal tissues of rats

BACKGROUND

Electrical biopsy illustrates a tissue's electrical properties by electrical impedance spectroscopy. However, electrical biopsy parameters are different from conventional morphological-based examinations. The correlation between electrical biopsy and the morphological observation has not been checked. Considering the tissue responses to injury, extracellular resistance should be most sensitive with the accumulation of fluid in tissue, and it is expected to increase the ratio of optical low staining area on histological images. In this study, we calculated the ratio of optical low staining area of sampled histological images and compared with the results of electrical biopsy to verify the hypothesis of that the extracellular resistance of electrical biopsy most highly correlates with the ratio of optical low staining area on histological images.

METHODS

The irradiated intestinal tissues of rats after different latent period were used for study. The sampled tissues were measured by electrical impedance spectroscopy for electrical biopsy and the microscopic images were acquired. The sampled histological images were transformed into the Hue-Saturation-Density (HSD) colour model to decouple the stain density. The ratio of optical low staining area on histological images was computed to quantify the morphological changes. The results were related to the parameters from electrical biopsy according to three element circuit model by Spearman's rank correlation test.

RESULTS

The ratio of optical low staining area varied as well as the tissue's electrical parameters. The extracellular resistance (Re) and intracellular resistance (Ri) by electrical biopsy tended to increase with the ratio of low staining area decreasing. The membrane capacitance (Cm) by electrical biopsy tended to increase with the ratio of optical low staining area increasing. The extracellular resistance (Re) of electrical biopsy was the parameter most highly correlated with the ratio of optical low staining area with a correlation coefficient of -0.757 (p < 0.001).

CONCLUSIONS

The results of this report confirm the hypothesis and support the idea that electrical biopsy results reflect the changes in tissues seen in conventional histological findings in a sense of conventional histological knowledge, and this approach may have a great potential for augmenting the pathological diagnosis of tissues.

Resting potential, oncogene-induced tumorigenesis, and metastasis: the bioelectric basis of cancer in vivo

Cancer may result from localized failure of instructive cues that normally orchestrate cell behaviors toward the patterning needs of the organism. Steady-state gradients of transmembrane voltage (V(mem)) in non-neural cells are instructive, epigenetic signals that regulate pattern formation during embryogenesis and morphostatic repair. Here, we review molecular data on the role of bioelectric cues in cancer and present new findings in the Xenopus laevis model on how the microenvironment's biophysical properties contribute to cancer in vivo. First, we investigated the melanoma-like phenotype arising from serotonergic signaling by 'instructor' cells-a cell population that is able to induce a metastatic phenotype in normal melanocytes. We show that when these instructor cells are depolarized, blood vessel patterning is disrupted in addition to the metastatic phenotype induced in melanocytes. Surprisingly, very few instructor cells need to be depolarized for the hyperpigmentation phenotype to occur; we present a model of antagonistic signaling by serotonin receptors that explains the unusual all-or-none nature of this effect. In addition to the body-wide depolarization-induced metastatic phenotype, we investigated the bioelectrical properties of tumor-like structures induced by canonical oncogenes and cancer-causing compounds. Exposure to carcinogen 4-nitroquinoline 1-oxide (4NQO) induces localized tumors, but has a broad (and variable) effect on the bioelectric properties of the whole body. Tumors induced by oncogenes show aberrantly high sodium content, representing a non-invasive diagnostic modality. Importantly, depolarized transmembrane potential is not only a marker of cancer but is functionally instructive: susceptibility to oncogene-induced tumorigenesis is significantly reduced by forced prior expression of hyperpolarizing ion channels. Importantly, the same effect can be achieved by pharmacological manipulation of endogenous chloride channels, suggesting a strategy for cancer suppression that does not require gene therapy. Together, these data extend our understanding of the recently demonstrated role of transmembrane potential in tumor formation and metastatic cell behavior. V(mem) is an important non-genetic biophysical aspect of the microenvironment that regulates the balance between normally patterned growth and carcinogenesis.

Review of electromagnetic techniques for breast cancer detection

Breast cancer is anticipated to be responsible for almost 40,000 deaths in the USA in 2011. The current clinical detection techniques suffer from limitations which motivated researchers to investigate alternative modalities for the early detection of breast cancer. This paper focuses on reviewing the main electromagnetic techniques for breast cancer detection. More specifically, this work reviews the cutting edge research in microwave imaging, electrical impedance tomography, diffuse optical tomography, microwave radiometry, biomagnetic detection, biopotential detection, and magnetic resonance imaging (MRI). The goal of this paper is to provide biomedical researchers with an in-depth review that includes all main electromagnetic techniques in the literature and the latest progress in each of these techniques.

Transcutaneous computed bioconductance measurement in lung cancer: a treatment enabling technology useful for adjunctive risk stratification in the evaluation of suspicious pulmonary lesions

Lung cancer is the number one cause of cancer deaths in North America and is rapidly increasing worldwide. Although there are advances being made in the multidisciplinary management and combined-modality therapies of lung cancers, most cases are still diagnosed in later noncurable stages. Early detection has hinged on clinical risk assessment and on the future possibility of screening by low-dose computed tomography of the chest; however, this will only vastly increase the number of indeterminate pulmonary lesions (IPLs) being detected. Given that the majority of radiographically detected lung lesions are benign, and tissue confirmation by various invasive biopsy tests has increased risks and costs, a noninvasive adjunctive test that can stratify likelihood of an indeterminate lung lesion as malignant or benign will be a useful treatment-enabling technology to speed up diagnosis and treatment of lung cancers at a more curable stage and defer unnecessary invasive procedures that have potential for harm. Measurement of transcutaneous bioconductance using the differential conductivity properties of cancerous versus benign tissue has been previously demonstrated on nonlung lesions. Thus, it has the potential of being a noninvasive, simple-to-perform and repeatable test that may be valuable in assessing lung lesions. In this prospective study of subjects with known thoracic malignancies, computed bioconductance measurements discriminated between malignant lesions (29 primary lung cancers) from benign pathology (12) across a range of IPL sizes (0.8 cm and greater) with a sensitivity of 89.7% (positive predictive value 96.3%) and specificity of 91.7% (negative predictive value 78.5%). The technology seems to be effective across a range of tumor thoracic locations, cell types, and stages. Additional cohorts of subjects will be used to validate testing and for refinement of the current algorithm, which at present has a test performance with a receiver operating characteristic of 90.7%. Noninvasive transcutaneous computed bioconductance measurement can become a standard risk assessment and therapy-enabling tool in the evaluation of IPLs.

BREAST IMAGING SYSTEMS: A REVIEW AND COMPARATIVE STUDY

Due to the successful union between computational technologies and basic laws of physics and biological sciences, many biomedical imaging systems now find significant presence in clinical settings, aiding physicians in diagnosing most forms of human illness with more confidence. In the case of breast imaging, apart from the basic diagnosis, these imaging systems also help in locating the abnormal tissues for biopsy, identifying the exact margins of the lesion for good lumpectomy results, staging and restaging the cancer, detecting locations of metastases, and planning and following up treatment protocols. It is well known that early detection of cancer is the only way to increase the survival rate of the patient. Without such imaging systems, it would be hard and almost impossible for the physicians to determine the nature and extent of the disease by merely simple physical examinations and biopsies. This article presents a description of most of these invaluable breast-imaging systems. Moreover, a comparison of these modalities and a review of a few of the developments these devices have come across over the years are also given.

A GMM-based breast cancer risk stratification using a resonance-frequency electrical impedance spectroscopy

PURPOSE

The authors developed and tested a multiprobe-based resonance-frequency-based electrical impedance spectroscopy (REIS) system. The purpose of this study was to preliminarily assess the performance of this system in classifying younger women into two groups, those ultimately recommended for biopsy during imaging-based diagnostic workups that followed screening and those rated as negative during mammography.

METHODS

A seven probe-based REIS system was designed, assembled, and is currently being tested in the breast imaging facility. During an examination, contact is made with the nipple and six concentric points on the breast skin. For each measurement channel between the center probe and one of the six external probes, a set of electrical impedance spectroscopy (EIS) signal sweeps is performed and signal outputs ranging from 200 to 800 kHz at 5 kHz interval are recorded. An initial subset of 174 examinations from an ongoing prospective clinical study was selected for this preliminary analysis. An initial set of 35 features, 33 of which represented the corresponding EIS signal differences between the left and right breasts, was established. A Gaussian mixture model (GMM) classifier was developed to differentiate between "positive" (biopsy recommended) cases and "negative" (nonbiopsy) cases. Selecting an optimal feature set was performed using genetic algorithms with an area under a receiver operating characteristic curve (AUC) as the fitness criterion.

RESULTS

The recorded EIS signal sweeps showed that, in general, negative (nonbiopsy) examinations have a higher level of electrical impedance symmetry between the two breasts than positive (biopsy) examinations. Fourteen features were selected by genetic algorithm and used in the optimized GMM classifier. Using a leave-one-case-out test, the GMM classifier yielded a performance level of AUC = 0.78, which compared favorably to other three widely used classifiers including support vector machine, classification tree, and linear discriminant analysis. These results also suggest that the REIS signal based GMM classifier could be used as a prescreening tool to correctly identify a fraction of younger women at higher risk of developing breast cancer (i.e., 47% sensitivity at 90% specificity).

CONCLUSIONS

The study confirms that asymmetry in electrical impedance characteristics between two breasts provides valuable information regarding the presence of a developing breast abnormality; hence, REIS data may be useful in classifying younger women into two groups of "average" and "significantly higher than average" risk of having or developing a breast abnormality that would ultimately result in a later imaging-based recommendation for biopsy.

A preliminary evaluation of multi-probe resonance-frequency electrical impedance based measurements of the breast

RATIONALE AND OBJECTIVES

The aim of this study was to preliminarily assess the performance of a new, resonance-frequency electrical impedance spectroscopy (REIS) system in identifying young women who were recommended to undergo breast biopsy following imaging.

MATERIALS AND METHODS

A seven-probe REIS system was designed and assembled and is currently being prospectively tested. During examination, contact is made with the nipple and six concentric points on the breast skin. Signal sweeps are performed, and outputs ranging from 200 to 800 kHz at 5-kHz intervals are recorded. An initial set of 140 patients, including 56 who eventually had biopsies, 63 who had negative results on screening mammography, and 21 recalled for additional imaging but later determined to have negative results, was used. An initial set of 35 features, 33 representing impedance signal differences between breasts and two representing participant age and average breast density, was assembled and reduced by a genetic algorithm to 14. The performance of an artificial neural network-based classifier was assessed using a case-based leave-one-out method.

RESULTS

The substantially greater asymmetry between signals of mirror-matched regions ascertained from biopsy ("positive") compared to nonbiopsy ("negative") cases resulted in an artificial neural network classifier performance (area under the curve) of 0.830 ± 0.023. At 90% specificity, this classifier, optimized for "recommendation for biopsy" rather than "cancer," detected 30 REIS-positive cases (54%), including six of nine (67%) actual cancer cases and six of nine women (67%) recommended for surgical excision of high-risk lesions.

CONCLUSIONS

Asymmetry in impedance measurements between bilateral breasts may provide valuable discriminatory information regarding the presence of highly suspicious imaging-based findings.

Improving breast cancer risk stratification using resonance-frequency electrical impedance spectroscopy through fusion of multiple classifiers

This study aims to improve breast cancer risk stratification. A seven-probe resonance-frequency-based electrical impedance spectroscopy (REIS) system was designed, assembled, and utilized to establish a data set of examinations from 174 women. Three classifiers, including artificial neural network (ANN), support vector machine (SVM), and Gaussian mixture model (GMM), were independently developed to predict the likelihood of each woman to be recommended for biopsy. The performances of these classifiers were compared, and seven fusion methods for integrating these classifiers were investigated. The results showed that among the three classifiers, the ANN yielded the highest performance with an area under the curve (AUC) of 0.81 for the receiver operating characteristic (ROC), while SVM and GMM achieved AUCs of 0.80 and 0.78, respectively. Improvements of up to 3% were obtained using fusion of the three classifiers, with the largest improvement obtained using either a "minimum score" rule or a "weighted sum" rule. Comparing different combinations of two out of the three classifiers, the weighted sum rule provided the most robust and consistent results, with AUCs of 0.81, 0.83, and 0.82 for the different combinations of ANN and SVM, ANN and GMM, and SVM and GMM, respectively. Furthermore, at 90% specificity, the ANN, the weighted sum- and min rule-based classifiers, all detected 67% of the verified cancer cases as compared with 50, 50, and 60% detection of the high risk cases, respectively. The study demonstrated that REIS examinations provide relevant information for developing breast cancer risk stratification tools and that using fusion of several not-fully-correlated classifiers can improve classification performance.

Analysis of energy utilization and body composition in kidney, bladder, and adrenal cancer patients

OBJECTIVE

To investigate resting energy expenditure (REE) and body composition and the relationship between substrate utilization and energy expenditure in urologic cancer patients.

PATIENTS AND METHODS

Measured resting energy expenditure (mREE) was detected by indirect calorimetry in 122 urologic cancer patients and 131 control subjects. Extracellular fluid (ECF), intracellular fluid (ICF), and total water (TW) were measured by bioelectrical impedance appliance. Fat oxidation rate (F-O), carbohydrate oxidation rate, fat mass (FM), and fat free mass (FFM) were further determined.

RESULTS

Compared with the controls, cancer patients showed significantly elevated mREE and mREE/FFM (P = 0.049; P < 0.001). Of all the cancer patients, 50% (n = 61) were hypermetabolic, 43.4% (n = 53) normometabolic, and 6.6% (n = 8) hypometabolic, whereas 35.1% (n = 46) of the controls were hypermetabolic, 56.5% (n = 74) normometabolic, and 8.4% (n = 11) hypometabolic. REE was correlated to substrate oxidation rate (R(2) = 0.710). Cancer patients exhibited no significant difference in FM, FM/body weight (BW) and FFM, compared with controls. Cancer patients presented no significant difference in TW compared with controls (P = 0.791), but they had increased ECF (P < 0.001) and decreased ICF (P < 0.001).

CONCLUSION

Aberrations in substrate utilization may contribute to the elevated energy expenditure in urologic cancer patients. Cancer type and pathologic stage are influential factors of REE.

Basic study of a diagnostic modality employing a new electrical impedance tomography (EIT) method for noninvasive measurement in localized tissues

The objective of this study is to develop a device for noninvasive local tissue electrical impedance tomography (EIT) using divided electrodes with guard electrodes and to validate its effectiveness using bioequivalent phantoms. For this purpose, we prepared a measurement device and bioequivalent phantoms, measured the electrical characteristics of the phantoms, and validated the method using the phantoms. Monolayer phantoms mimicking the brain and muscle and bilayer phantoms consisting of muscle and brain layers were prepared. The relative differences between the measured electrical conductivities of the monolayer brain and muscle phantoms and the true values determined by the 4-electrode method were both less than 10%. The relative differences between the measured and true values in the bilayer phantoms were less than 20% in both layers. The biological impedance measurement device that we developed was confirmed to be effective for impedance measurement in bilayer phantoms with different electrical impedances. To develop a device for the early diagnosis of breast diseases, the development of a multi-layer phantom and demonstration of the effectiveness of the device for its examination are necessary. If the device that we developed makes impedance measurement in breast tumors possible, it may be used as a new diagnostic modality for breast diseases.

Comparison of three kinds of electrode-skin interfaces for electrical impedance scanning

Low, uniform, and stable electrode-skin impedance is required to achieve good performance of the electrode-skin interface for electrical impedance scanning (EIS) examination. This can be used to measure the real impedance distribution of breast tissue beneath the skin. In this study, the gel interface, the cotton fine grid thin layer (CFGTL) interface, and the hydrogel interface were compared. Experiments were conducted to assess the influence of each interface on the multi-frequency EIS data and their capacity to retain moisture. Results showed that the CFGTL and hydrogel interfaces decreased contact impedance and made the impedance between the electrodes and the breast skin more even and stable. The Cole-Cole model was also used to fit the multi-frequency EIS data. The results demonstrated that the CFGTL and hydrogel interfaces were advantageous for measuring the impedance of the breast tissue under the gel interface. In general, the CFGTL and hydrogel interfaces had good contact with the skin, and both interfaces were proper choices for EIS examination at present. The hydrogel interface was a better choice for our new EIS system.

Modern breast cancer detection: a technological review

Breast cancer is a serious threat worldwide and is the number two killer of women in the United States. The key to successful management is screening and early detection. What follows is a description of the state of the art in screening and detection for breast cancer as well as a discussion of new and emerging technologies. This paper aims to serve as a starting point for those who are not acquainted with this growing field.

Bioelectric controls of cell proliferation: ion channels, membrane voltage and the cell cycle

All cells possess long-term, steady-state voltage gradients across the plasma membrane. These transmembrane potentials arise from the combined activity of numerous ion channels, pumps and gap junction complexes. Increasing data from molecular physiology now reveal that the role of changes in membrane voltage controls, and is in turn controlled by, progression through the cell cycle. We review recent functional data on the regulation of mitosis by bioelectric signals, and the function of membrane voltage and specific potassium, sodium and chloride ion channels in the proliferation of embryonic, somatic and neoplastic cells. Its unique properties place this powerful, well-conserved, but still poorly-understood signaling system at the center of the coordinated cellular interactions required for complex pattern formation. Moreover, disregulation of ion channel expression and function is increasingly observed to be not only a useful marker but likely a functional element in oncogenesis. New advances in genomics and the development of in vivo biophysical techniques suggest exciting opportunities for molecular medicine, bioengineering and regenerative approaches to human health.

The use of skin surface electropotentials for breast cancer detection--preliminary clinical trial results obtained using the biofield diagnostic system

The purpose of this study is to evaluate the efficiency of the Biofield Diagnostic System (BDS) as an adjunct to established diagnostic techniques such as mammography and ultrasound in differentiating benign and malignant breast lesions. The clinical trial was conducted at the Tan Tock Seng hospital, Singapore. 103 women scheduled for mammography and/or ultrasound tests participated in the study. The BDS test recorded a sensitivity of 100%, specificity of 97.6%, and an accuracy of 98.1%. The area under the ROC curve was 0.988 which was slightly lower than that of ultrasound (0.994) and slightly higher than that of mammography (0.951). The BDS test has demonstrated high sensitivity and specificity values in the studied population. The accuracy is also comparable to that of diagnostic techniques like mammography and ultrasound. Thus, it is evident that BDS can be a fast and reliable adjunct tool for getting a secondary opinion on lesions with indeterminate mammographic and sonographic results.

Detection of breast abnormalities using a prototype resonance electrical impedance spectroscopy system: a preliminary study

Electrical impedance spectroscopy has been investigated with but limited success as an adjunct procedure to mammography and as a possible pre-screening tool to stratify risk for having or developing breast cancer in younger women. In this study, the authors explored a new resonance frequency based [resonance electrical impedance spectroscopy (REIS)] approach to identify breasts that may have highly suspicious abnormalities that had been recommended for biopsies. The authors assembled a prototype REIS system generating multifrequency electrical sweeps ranging from 100 to 4100 kHz every 12 s. Using only two probes, one in contact with the nipple and the other with the outer breast skin surface 60 mm away, a paired transmission signal detection system is generated. The authors recruited 150 women between 30 and 50 years old to participate in this study. REIS measurements were performed on both breasts. Of these women 58 had been scheduled for a breast biopsy and 13 had been recalled for additional imaging procedures due to suspicious findings. The remaining 79 women had negative screening examinations. Eight REIS output signals at and around the resonance frequency were computed for each breast and the subtracted signals between the left and right breasts were used in a simple jackknifing method to select an optimal feature set to be inputted into a multi-feature based artificial neural network (ANN) that aims to predict whether a woman's breast had been determined as abnormal (warranting a biopsy) or not. The classification performance was evaluated using a leave-one-case-out method and receiver operating characteristics (ROC) analysis. The study shows that REIS examination is easy to perform, short in duration, and acceptable to all participants in terms of comfort level and there is no indication of sensation of an electrical current during the measurements. Six REIS difference features were selected as input signals to the ANN. The area under the ROC curve (A(z)) was 0.707 +/- 0.033 for classifying between biopsy cases and non-biopsy (including recalled and screening negative) and the performance (A(z)) increased to 0.746 +/- 0.033 after excluding recalled but negative cases. At 95% specificity, the sensitivity levels were approximately 20.5% and 30.4% in the two data sets tested. The results suggest that differences in REIS signals between two breasts measured in and around the tissue resonance frequency can be used to identify at least some of the women with suspicious abnormalities warranting biopsy with high specificity.

The Use of Tissue Electrical Characteristics for Breast Cancer Detection: A Perspective Review

Breast cancer is the most frequently occurring malignancy in women. It is characterized by a high mortality rate. For the purpose of detecting this life threatening disease, research efforts are being made worldwide to exploit new technologies, to improve the detection accuracy of current devices and to develop new detection devices, comprehensive diagnostic procedures, and protocols. One such technology that is gaining popular attention over the recent years is the usage of electrical characteristics of the breast tissue to differentiate normal and cancerous tissues. Most of the devices using this technology are currently being used as adjunct diagnostic tools to improve the detection accuracy of established techniques like mammography and ultrasound. Also, early detection of breast cancer can help save many thousands of lives every year and can also reduce unnecessary healthcare expenditure caused by advanced stage treatment options. Hence, more research is also being done to adapt these devices into screening tools for early detection of breast cancer.

The main objective of this review is to highlight the features of the currently available commercial devices that use this technology for breast cancer detection. The electrical behavior of normal and cancerous breast tissues is first presented. The various commercial devices that utilize electrical impedance or electropotentials for breast cancer detection are then described. Finally, conclusions and potential areas of research are highlighted.

Prospective trial evaluating electrical impedance scanning of thyroid nodules before thyroidectomy: final results

BACKGROUND

Electrical impedance scanning (EIS) identifies tissue impedance changes associated with malignancy. Methods to distinguish benign from malignant thyroid nodules, particularly in patients with indeterminate cytology are lacking.

PURPOSE

To determine the diagnostic accuracy of EIS in the preoperative evaluation of thyroid nodules.

PATIENTS AND METHODS

From September 2002 to December 2006, 216 patients underwent thyroid fine needle aspiration (FNA) and EIS prethyroidectomy in this prospective cohort study. EIS, either positive or negative for malignancy, was correlated with final histopathology. A focal bright spot over a thyroid nodule correlating with increased conductivity and/or capacitance >25% baseline sternocleidomastoid muscle impedance defined positive EIS. Study endpoints were EIS accuracy, sensitivity (Sn), specificity (Sp), positive predictive value (PPV), and negative predictive value (NPV). This study has been registered in the National Institutes of Health's public trials registry at ClinicalTrials.gov. The registration number is NCT00571077.

RESULTS

EIS correctly diagnosed 96 of 110 patients with malignant and 75 of 106 patients with benign dominant thyroid nodules: Sn = 87%, Sp = 71%, PPV = 76%, NPV = 84%: overall EIS accuracy = 79%. Pretest cancer probability of 51% (110 of 216) increased to 76% (96 of 127) post-EIS, and preoperative use of EIS would result in a significant reduction (71%, 75 of 106) in number of operations performed for benign nodules. EIS performance was similar for 109 patients with indeterminate FNA: Sn = 83%, Sp = 67%, PPV = 61%, NPV = 87%, accuracy = 73%. Pretest probability of cancer increased from 39% (42 of 109) to 61% (35 of 57) post-EIS. The use of EIS would result in a significant reduction (67%, 45 of 67) in the number of purely diagnostic thyroidectomy for indeterminate FNA.

CONCLUSION

EIS shows promise in differentiating thyroid nodules. Further EIS hardware and software optimization is warranted to improve upon the already favorable negative predictive value in indeterminate thyroid nodules.

Electromagnetic breast imaging: results of a pilot study in women with abnormal mammograms

PURPOSE

To prospectively assess quantitatively the inherent contrast of electromagnetic (EM) properties that can be imaged by using available technology in women with abnormal findings at conventional breast imaging who underwent subsequent biopsy.

MATERIALS AND METHODS

The protocol was HIPAA compliant and approved by the institutional review board. All participants provided informed consent. Fifty-three women with normal (Breast Imaging Reporting and Data System [BI-RADS] category 1) and ninety-seven women with abnormal (BI-RADS category 4 or 5) screening mammograms were imaged with three EM imaging methods: electrical impedance spectroscopy (EIS), microwave imaging spectroscopy (MIS), and near-infrared spectral tomography (NIR). A region-of-interest (ROI) analysis was used to assess the EM image properties for comparison of findings with conventional image findings and correlation with specific pathologic parameters for women with abnormal findings. Statistical analyses were conducted.

RESULTS

One hundred fifty participants (age range, 35-81 years) were included. EM image property contrast ratios of 150%-200% were found in breast abnormality ROIs relative to the ipsilateral breast background. Analysis of variance demonstrated significant differences in ROI image summaries of mammographically normal versus abnormal breasts for EIS, across diagnostic groups for NIR, and for MIS (analysis restricted to lesions larger than 1 cm(3)). Receiver operating curve (ROC) analysis of the EM properties for cancers among subjects with BI-RADS category 4 or 5, compared with the EM properties for the subjects with normal breasts (BI-RADS category 1), yielded areas under the ROC curve ranging from 0.67 to 0.81. Pathologic correlations with mean vessel density, mean vessel area, and epithelium-to-stroma ratio suggest a biological origin of the EM image properties associated with disease.

CONCLUSION

Results from EM breast examinations provide statistical evidence of a mean increase in image contrast of 150%-200% between abnormal (benign and malignant) and normal breast tissue.

Prospective study of electrical impedance scanning for identifying young women at risk for breast cancer

BACKGROUND

One way to improve the cost-benefit ratio for breast cancer screening in younger women is to identify those at high-risk of breast cancer and manage them in an optimal manner. The purpose of this study is to evaluate the sensitivity and specificity of Electrical Impedance Scanning (EIS) for identifying young women who are at risk for having breast cancer and should be followed with directed imaging technologies.

METHODS

A prospective, observational, two-arm, multi-site clinical trial was performed on women aged 30-45 years. The 'Sensitivity Arm' included Clinical Breast Examinations (CBE) and EIS (T-Scan 2000ED) on 189 women prior to scheduled breast biopsy. The 'Specificity Arm' included 1361 asymptomatic women visiting clinics for routine annual well-woman examination. Sensitivity and specificity were determined. Relative probability for a woman with a positive EIS examination was computed and compared with other approaches commonly used to define 'high-risk' in this population.

RESULTS

Fifty of 189 women in the Sensitivity arm had verified cancers, 19 of whom had positive EIS examination resulting in sensitivity of 38% (19/50). Of the 1361 women in the Specificity arm, 67 had positive EIS examination resulting in a specificity of 95% (1294/1361). The relative probability of a woman with a positive EIS examination was 7.68, which compares favorably with other established risk identifiers (e.g. two first-degree relatives with breast cancer or atypical ductal hyperplasia).

CONCLUSION

EIS may have an important role as a screening tool for identifying young women that should be followed more closely with advanced imaging technologies for early detection of breast cancer.