The use of electrical impedance spectroscopy in the detection of cervical intraepithelial neoplasia

Detection of High-Grade Cervical Intraepithelial Neoplasia by Electrical Impedance Spectroscopy in Women Diagnosed with Low-Grade Cervical Intraepithelial Neoplasia in Cytology

The authors attempt to address the importance of timely detection and management of cervical intraepithelial neoplasia (CIN) to prevent cervical cancer. The study focused on the potential of electrical impedance spectroscopy (EIS) as an adjunct to colposcopy, aiming to enhance the accuracy of identifying high-grade cervical lesions. Colposcopy, a widely used technique, exhibited variable sensitivity in detecting high-grade lesions, which relies on the expertise of the operator. The study's primary objective is to evaluate the effectiveness of combining colposcopy with EIS in detecting high-grade cervical lesions among patients initially diagnosed with low-grade CIN based on cytology. We employed a cross-sectional observational design, recruiting 101 women with abnormal cervical cytology results. The participants underwent colposcopy with acetic acid and subsequent EIS using the ZedScan device. The ZedScan results are categorized into color-coded probability levels, with red indicating the highest likelihood of high-grade squamous intraepithelial lesions (HSIL) occurrence. Results revealed that ZedScan exhibits a sensitivity rate of 89.5% and a specificity rate of 84% for detecting high-grade lesions. Colposcopy, on the other hand, recorded a sensitivity rate of 85.5% and a specificity rate of 92%. The agreement rate between ZedScan and biopsy is 79.2%, as indicated by a kappa coefficient of 0.71, while the agreement rate between colposcopy and biopsy is 74.3%, with a kappa coefficient of 0.71.

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

Objective

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

Study Design

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

Results

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

Conclusion

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

Diagnostic comparison of electrical impedance spectroscopy with colposcopy and HPV mRNA-testing in the prediction of CIN2+ women in Greece

AIM

To compare the diagnostic parameters of electrical impedance spectroscopy (EIS) via ZedScan, a device that measures spectra to differentiate between normal and abnormal cervical tissues, when used as an adjunct to colposcopies in the diagnosis of HSILs/CIN2+ in Greek women with abnormal referral cytology toward colposcopy alone and HPV mRNA-testing.

METHODS

This study analyzed 86 women, patients of the Colposcopy and Cervical Pathology Clinic of 2nd Obstetrics and Gynecology Department, Aristotle University of Thessaloniki at Hippokration General Hospital, between January 2022 and September 2022. During the visits, women were subjected to cytology, colposcopy alone and then with EIS/ZedScan and histological sampling.

RESULTS

Common use of colposcopies and EIS/ZedScan allowed detecting an additional 14 cases of CIN2+ (16.2%) that colposcopy alone failed to report. EIS enhanced the sensitivity of colposcopy from 80.65% to 100% equal with that of HPV-mRNA test while retaining a high specificity (94.74%) which is much higher than specificity of HPV mRNA-testing (65.45%). EIS-assisted colposcopy had the highest value combination of positive and negative predictive values (96.15% and 100%) compared to colposcopy alone (100% and 75%) and HPV mRNA-testing (72.46% and 100%).

CONCLUSIONS

Colposcopies performed with EIS/ZedScan demonstrated effectiveness in the diagnosing of CIN2+ leading to a significant increase in the number of CIN2+ that would have been missed if only colposcopy was applied especially in women with LSIL referral cytology. EIS/ZedScan seems to possess the ideal diagnostic threshold for sensitivity, specificity, and predictive values for CIN2+ compared to colposcopy alone and HPV mRNA-testing.

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

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

Clinical evaluation of a real-time optoelectronic device in cervical cancer screening

OBJECTIVE

Early screening and intervention are crucial for the prevention and treatment of cervical cancer. TruScreen is a real-time, intelligent, pathological diagnostic technology designed for cervical cancer screening. The aim of this study was to evaluate the clinical value of TruScreen in screening for cervical lesions.

STUDY DESIGN

A total of 458 women aged between 25 and 65 years were recruited to receive cervical cancer screening, including human papillomavirus (HPV) testing, cytological testing using the ThinPrep cytology test (TCT), and TruScreen from December 2018 to January 2020. The clinical performance of TruScreen, alone and in combination with HPV testing, was evaluated to detect cervical intraepithelial neoplasia grade 2 or worse (CIN2+ or CIN3+).

RESULTS

For detection of CIN2+, the sensitivity and specificity of TruScreen were 83.78% and 78.86%, respectively. The specificity of TruScreen was significantly higher than those of HPV testing (50.59%, P < 0.001) and TCT (55.58%, P < 0.001). In high-risk HPV-positive women, the specificity of HPV testing combined with TruScreen was significantly higher than that of HPV testing combined with TCT (50% vs 39.9%, P = 0.004). The sensitivity of HPV testing combined with TruScreen was comparable to that of HPV testing combined with TCT (93.94% vs 87.88%, P = 0.625). Similar patterns were also observed for CIN3+ cases.

CONCLUSION

TruScreen has the potential for screening high-grade cervical precancerous lesions and may replace cytological tests as a cervical cancer screening method in China to avoid subjectivity in the interpretation of cytological tests and requirements by pathologists.

Virtual Biopsy by Electrical Impedance Spectroscopy in Barrett's Carcinoma

Purpose

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

Methods

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

Results

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

Conclusion

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

Trial Registration

NCT04046601

Cervical Cancer Prognosis and Diagnosis Using Electrical Impedance Spectroscopy

Electrical impedance spectroscopy (EIS) has been used as an adjunct to colposcopy for cervical cancer diagnosis for many years, Currently, the template match method is employed for EIS measurements analysis, where the measured EIS spectra are compared with the templates generated from three-dimensional finite element (FE) models of cancerous and non-cancerous cervical tissue, and the matches between the measured EIS spectra and the templates are then used to derive a score that indicates the association strength of the measured EIS to the High-Grade Cervical Intraepithelial Neoplasia (HG CIN). These FE models can be viewed as the computational versions of the associated physical tissue models. In this paper, the problem is revisited with an objective to develop a new method for EIS data analysis that might reveal the relationship between the change in the tissue structure due to disease and the change in the measured spectrum. This could provide us with important information to understand the histopathological mechanism that underpins the EIS-based HG CIN diagnostic decision making and the prognostic value of EIS for cervical cancer diagnosis. A further objective is to develop an alternative EIS data processing method for HG CIN detection that does not rely on physical models of tissues so as to facilitate extending the EIS technique to new medical diagnostic applications where the template spectra are not available. An EIS data-driven method was developed in this paper to achieve the above objectives, where the EIS data analysis for cervical cancer diagnosis and prognosis were formulated as the classification problems and a Cole model-based spectrum curve fitting approach was proposed to extract features from EIS readings for classification. Machine learning techniques were then used to build classification models with the selected features for cervical cancer diagnosis and evaluation of the prognostic value of the measured EIS. The interpretable classification models were developed with real EIS data sets, which enable us to associate the changes in the observed EIS and the risk of being HG CIN or developing HG CIN with the changes in tissue structure due to disease. The developed classification models were used for HG CIN detection and evaluation of the prognostic value of EIS and the results demonstrated the effectiveness of the developed method. The method developed is of long-term benefit for EIS-based cervical cancer diagnosis and, in conjunction with standard colposcopy, there is the potential for the developed method to provide a more effective and efficient patient management strategy for clinic practice.

Comparison of the detection rate of cervical lesion with TruScreen, LBC test and HPV test: A Real-world study based on population screening of cervical cancer in rural areas of China

BACKGROUND AND OBJECTIVE

China carries a heavy burden of cervical cancer and has an alarmingly low cervical cancer screening rate. In order to achieve the goal of cervical cancer elimination, there is an urgent need for suitable methods and strategies in China.

MATERIALS AND METHODS

A total 9972 woman who received cervical cancer screening services of National Cervical Cancer Screening Program in Rural Areas (NCCSPRA) in 8 project counties participated in this study. TruScreen, HPV test and LBC test were performed in all participants. A total of 1945women had one or more than one positive or abnormal screening results of the above three screening tests subsequently received colposcopy. The detection rate of CIN2+ between the three tests were compared.

RESULTS

No matter what kind of screening method is used, the CIN2+ detection rate in the eastern regions was much higher than that in the central and western regions. The total detection rate of CIN2+ in HPV group was highest (0.73%), following in LBC group (0.44%) and TS group (0.31%). There was statistically significant difference in the total detection rate of CIN2+ between TS and HPV groups, LBC and HPV groups, respectively. There was no statistical difference in the total detection rate of CIN2+ between TS and LBC screening groups. Moreover, except for the eastern regions, there was no statistical difference in the detection rate of CIN2+ between TS group and the other two groups in central and western regions.

CONCLUSION

If it can meet the requirements of the laboratory and personnel, HPV test seems to be the preferred method for cervical cancer screening in rural areas of China. The characteristics of minimal training requirements, simple operation, real-time results obtained without the collection of cervical cell samples and the help of laboratory equipment and cytologists of TS make it ideal for cervical cancer screening in low-resource regions.

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.

Use of Electrical Impedance Spectroscopy for Intraoperative Tissue Differentiation During Thyroid and Parathyroid Surgery

BACKGROUND

Electrical impedance (EI) measures tissue resistance to alternating current across several frequencies and may help identify tissue type. A recent rabbit model demonstrated that electrical impedance spectroscopy (EIS) may facilitate identification of parathyroid glands and potentially improve outcomes following surgery. This study looks at the EI patterns of soft tissues in the human neck to determine whether parathyroid tissue can be accurately identified.

METHODS

This was a phase 1, single-arm interventional study involving 56 patients undergoing thyroid and/or parathyroid surgery. Up to 12 EI readings were taken from in vivo and ex vivo thyroid and parathyroid glands, adipose tissue and muscle of each patient. Each reading consists of a series of measurements over 14 frequencies from each tissue. EI patterns were analysed. Two patients were excluded due to data loss due to device malfunction.

RESULTS

The median age of participants was 53.5 (range 20-85) years. Thirty-five participants had surgery for thyroid pathology, 17 for parathyroid pathology and four for both. Six hundred and six EIS spectra were reviewed for suitability. One hundred and eighty-four spectra were rejected leaving 422 spectra for analysis. The impedance patterns of the soft tissues differed by histological type. The EI ratio of low (152 Hz) to high (312 kHz) frequencies demonstrated a significant difference between the soft tissues (p = 0.006). Using appropriate thresholds, parathyroid tissue can be distinguished from thyroid tissue with a sensitivity of 76% and specificity of 60%.

CONCLUSIONS

This study demonstrates the feasibility of using EIS to aid parathyroid identification and preservation. Further changes to the device and modelling of the EI patterns across the range of frequencies may improve accuracy and facilitate intraoperative use.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT02901873).

Adjunctive colposcopy technologies for assessing suspected cervical abnormalities: systematic reviews and economic evaluation

BACKGROUND

Dynamic Spectral Imaging System (DySIS)map (DySIS Medical Ltd, Edinburgh, UK) and ZedScan (Zilico Limited, Manchester, UK) can be used adjunctively with conventional colposcopy, which may improve the detection of cervical intraepithelial neoplasia (CIN) and cancer.

OBJECTIVES

To systematically review the evidence on the diagnostic accuracy, clinical effectiveness and implementation of DySISmap and ZedScan as adjuncts to standard colposcopy, and to develop a cost-effectiveness model.

METHODS

Four parallel systematic reviews were performed on diagnostic accuracy, clinical effectiveness issues, implementation and economic analyses. In January 2017 we searched databases (including MEDLINE and EMBASE) for studies in which DySISmap or ZedScan was used adjunctively with standard colposcopy to detect CIN or cancer in women referred to colposcopy. Risk of bias was assessed with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 tool. Summary estimates of diagnostic accuracy were calculated using bivariate and other regression models when appropriate. Other outcomes were synthesised narratively. A patient-level state-transition model was developed to evaluate the cost-effectiveness of DySISmap and ZedScan under either human papillomavirus (HPV) triage or the HPV primary screening algorithm. The model included two types of clinics ['see and treat' and 'watchful waiting' (i.e. treat later after confirmatory biopsy)], as well as the reason for referral (low-grade or high-grade cytological smear). Sensitivity and scenario analyses were undertaken.

RESULTS

Eleven studies were included in the diagnostic review (nine of DySISmap and two of ZedScan), three were included in the clinical effectiveness review (two of DySISmap and one of ZedScan) and five were included in the implementation review (four of DySISmap and one of ZedScan). Adjunctive DySISmap use was found to have a higher sensitivity for detecting CIN grade 2+ (CIN 2+) lesions [81.25%, 95% confidence interval (CI) 72.2% to 87.9%] than standard colposcopy alone (57.91%, 95% CI 47.2% to 67.9%), but with a lower specificity (70.40%, 95% CI 59.4% to 79.5%) than colposcopy (87.41%, 95% CI 81.7% to 91.5%). (Confidential information has been removed.) The base-case cost-effectiveness results showed that adjunctive DySISmap routinely dominated standard colposcopy (it was less costly and more effective). The only exception was for high-grade referrals in a watchful-waiting clinic setting. The incremental cost-effectiveness ratio for ZedScan varied between £272 and £4922 per quality-adjusted life-year. ZedScan also dominated colposcopy alone for high-grade referrals in see-and-treat clinics. These findings appeared to be robust to a wide range of sensitivity and scenario analyses.

LIMITATIONS

All but one study was rated as being at a high risk of bias. There was no evidence directly comparing ZedScan with standard colposcopy. No studies directly compared DySIS and ZedScan.

CONCLUSIONS

The use of adjunctive DySIS increases the sensitivity for detecting CIN 2+, so it increases the number of high-grade CIN cases that are detected. However, it also reduces specificity, so that more women with no or low-grade CIN will be incorrectly judged as possibly having high-grade CIN. The evidence for ZedScan was limited, but it appears to increase sensitivity and decrease specificity compared with colposcopy alone. The cost-effectiveness of both adjunctive technologies compared with standard colposcopy, under both the HPV triage and primary screening algorithms, appears to be favourable when compared with the conventional thresholds used to determine value in the NHS.

FUTURE WORK

More diagnostic accuracy studies of ZedScan are needed, as are studies assessing the diagnostic accuracy for women referred to colposcopy as part of the HPV primary screening programme.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017054515.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

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.

Cervicouterine Cancer Screening - TruScreen™ vs. Conventional Cytology: Pilot Study

Introduction:

Cervicouterine cancer (CC) is a health problem worldwide and is the fourth most common cancer in women, with a greater proportion of individuals affected by advanced stages of the disease in developing countries.

Objective:

To determine the sensitivity and specificity of the TruScreen™ opto-electronic device vs. conventional cytology in CC screenings.

Methodology:

This is a prospective observational study that included individuals who presented for the first time at the Dysplasia Clinic of the Instituto Nacional de Cancerología from March 1 through April 30, 2016, and those referred due to abnormal conventional cytology. The patients were evaluated with the TruScreen™ device, conventional cytology, colposcopy and, if necessary, cervical biopsy. The results were analyzed by descriptive statistics as well as the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the TruScreen™, using conventional cytology as the standard.

Results:

Thirty-two patients were included who met the inclusion criteria. The average age of the patients was 40 years (range, 23–61 years). For the diagnosis of high-grade intraepithelial lesions, the TruScreen™ device showed a 43% sensitivity, a 92% specificity, a PPV of 60%, and a NPV of 85%, whereas evaluation via cervical biopsy exhibited a 33% sensitivity, an 86% specificity, a 33% PPV, and an 86% NPV. The Kappa agreement index of the TruScreen™ with the colposcopies was 0.70.

Conclusions:

TruScreen™ demonstrated low sensitivity and high specificity compared with conventional cytology, which had a high NPV.

Use of a Conical Conducting Layer with an Electrical Impedance Probe to Enhance Sensitivity in Epithelial Tissues

Tetra-polar electrical impedance measurement (TPIM) with a square geometry of electrodes is useful in the characterization of epithelial tissues, especially in the detection of cervical cancer at precancerous stages. However, in TPIM, the peak planar sensitivity just below the electrode surface is almost zero and increases to a peak value at a depth of about one third to one half of the electrode separation. To get high sensitivity for the epithelial layer, having thicknesses of 200 μm to 300 μm, the electrode separation needed is less than 1 mm, which is difficult to achieve in practical probes. This work proposes a conical conducting layer in front of a pencil like probe with a square geometry of TPIM electrodes to create virtual electrodes with much smaller separation at the body surface, thus increasing the sensitivity of the epithelial tissues. To understand the improvements, if any, 3D sensitivity distribution and transfer impedance were simulated using COMSOL Multiphysics software for a simplified body tissue model containing a 300 μm epithelial layer. It has been shown that fractional contribution of an epithelial layer can be increased several times placing a cylindrical conducting layer in between the tissue surface and the electrodes, which can further be enhanced using a conical conducting layer. The results presented in this paper can be used to choose an appropriate electrode separation, conducting layer height and cone parameters for enhanced sensitivity in the epithelial layer.

The impact of using electrical impedance spectroscopy (ZedScan) on the performance of colposcopy in diagnosing high grade squamous lesions of the cervix

OBJECTIVES

To determine the efficacy of colposcopy plus ZedScan, which measures changes in tissue electrical impedance, for detecting intraepithelial high-grade lesions compared to colposcopy alone.

METHODS

A prospective study conducted at a university hospital colposcopy clinic. Patients referred following abnormal cervical cytology or colposcopic follow up were examined by colposcopy plus ZedScan to assess the cervix. The results of ZedScan directed and colposcopically directed biopsies were compared.

RESULTS

Ninety-one patients were included in this study. The median age was 33 years. Eighty (88%) were referred with abnormal cytology; LSIL 45%, ASCUS 27%, ACS-H 8%, HSIL 7%, AGC 1% and 12% follow-up postconisation or colposcopic follow up. Colposcopy alone detected 18 high-grade lesions with 64 women undergoing biopsy with a total of 115 biopsies being taken with a sensitivity of 60% and NPV estimated at 81.7%. ZedScan with colposcopy increased the detection of high-grade lesions by 47.3%, identifying 27 high-grade lesions and one case of invasive cancer. Sensitivity was 93.1% and NPV estimated at 91.3%. A combination of normal colposcopy practice and ZedScan had a sensitivity and NPV of 100%.

CONCLUSION

ZedScan used in conjunction with the colposcopy improves sensitivity in detecting high-grade lesions at the expense of a moderate increase in the number of biopsies.

Alternative Colposcopy Techniques: A Systematic Review and Meta-analysis

OBJECTIVE

To assess the diagnostic value of alternative (digital) colposcopy techniques for detection of cervical intraepithelial neoplasia (CIN) 2 or worse in a colposcopy population.

DATA SOURCES

MEDLINE, EMBASE, ClinicalTrials.gov, and the Cochrane Library were searched from inception up to January 11, 2016, for studies that evaluated the diagnostic value of alternative (digital) colposcopy techniques.

METHODS OF STUDY SELECTION

Inclusion criteria were: 1) an alternative (digital) colposcopy technique was used in a colposcopy population; 2) a histologic outcome was reported, classified as CIN, differentiating between mild dysplasia or less (CIN 1 or less), and moderate dysplasia or worse (CIN 2 or greater); 3) the entire cervix was scanned at once or a per-woman analysis was performed; 4) no other topical application than acetic acid and Lugol's solution was used; 5) at least three eligible studies had to be available within a single technique; and 6) studies obtained research ethics approval. Language was restricted to English.

TABULATION, INTEGRATION, AND RESULTS

Two reviewers assessed the eligibility of the identified articles. Disagreements were resolved by a third reviewer. Thirteen studies met the inclusion criteria. We found six studies on fluorescence and reflectance spectroscopy, including 2,530 women, with a pooled sensitivity of 93% (95% confidence interval [CI] 89-95%) and specificity of 62% (95% CI 47-76%). Four studies on dynamic spectral imaging were found including 1,173 women with a pooled sensitivity of 69% (95% CI 48-85%) and specificity of 83% (95% CI 76-88%). We found three studies on optical coherence tomography including 693 women with a pooled sensitivity of 48% (95% CI 32-64%) and specificity of 77% (95% CI 52-91%). Previously published conventional colposcopy results showed a sensitivity of 61% (95% CI 58-63%) and a specificity of 85% (95% CI 83-86%).

CONCLUSION

Alternative (digital) colposcopy techniques may result in increased sensitivity and specificity, but no recommendation for introduction in clinical practice can be made yet.

Magnetic induction spectroscopy (MIS)-probe design for cervical tissue measurements

OBJECTIVE

Gradiometers have the advantage of increasing measuring sensitivity, which is particularly useful in magnetic induction spectroscopy (MIS) for bio-impedance measurements. Traditional gradiometers use a pair of field sensing coils equally distant and on opposite sides of a drive coil, which provides high immunity to interference. In this paper, a ferrite-cored coaxial gradiometer probe of 29 mm diameter has been developed for measuring the impedance spectra of cervical tissues in vivo.

APPROACH

It consists of a ferrite rod with outer ferrite confinement screening in order to eliminate the signals from surrounding tissue. The magnetic screening efficiency was compared with an air-cored gradiometer probe. For both gradiometer probes, a drive coil and two sensing coils were wound on a borosilicate glass former aligned coaxially with two sensing coils equidistant from the drive coil. The signal sensitivity of those two MIS gradiometers has been measured using saline samples with a conductivity range between 0.1 and 1.1 S m^-1. Finite element methods using COMSOL Multiphysics have been used to simulate the distribution of sensitivity to conductivity over the face of each probe and with depth.

MAIN RESULTS

The ferrite-cored probe has a sensitivity confined to the volume defined by the gap between the ferrite core and outer tube of ferrite while the air-cored probe without any magnetic shielding had a wide sensitivity over the face and the side of the probe. Four saline samples and one of distilled water with conductivities from 0.1 to 1.1 S m^-1 have been used to make conductivity measurements at frequencies of 50 kHz, 100 kHz, and 300 kHz. The measurement accuracy of the air-cored MIS probe was 0.09 S m^-1 at 50 kHz, improving to 0.05 S m^-1 at 300 kHz. For the ferrite-cored MIS probe, the measurement accuracy was 0.28 S m^-1 at 50 kHz, improving to 0.04 S m^-1 at 300 kHz.

SIGNIFICANCE

In vivo measurements on human hand have been performed using both types of gradiometers and the conductivity is consistent with reported data.

Detecting colorectal cancer using electrical impedance spectroscopy: an ex vivo feasibility study

OBJECTIVE

Colorectal cancer is the fourth most common cancer worldwide, with a lifetime risk of around 20%. Current techniques do not allow clinicians to objectively assess tissue abnormality during endoscopy and perioperatively. A method capable of objectively assessing samples in real time and which can be included in minimally invasive diagnostic and management strategies would be highly transformative. Electrical impedance spectroscopy (EIS) may provide such a solution. This paper presents a feasibility study on using EIS in assessing colorectal tissue.

APPROACH

We performed tetrapolar EIS using ZedScan on excised human colorectal tumour tissue and the matched normal colonic mucosa in 22 freshly resected specimens following elective surgery for colorectal cancer. Histopathological examination was used to confirm the final diagnosis. Statistical significance was assessed using the Wilcoxon signed rank test.

MAIN RESULTS

Tetrapolar EIS could discriminate cancer with statistically significant results when applying frequencies between 305 Hz and 625 kHz (p  <  0.05). 300 Ω was set as the transfer impedance threshold to detect cancer. Thus, the area under the corresponding receiver operating characteristic curve for this threshold was 0.7105.

SIGNIFICANCE

This feasibility study demonstrates that impedance spectra changes in colorectal cancer tissue are detectable and may be statistically significant, suggesting that EIS has the potential to be the core technology in a novel non-invasive point of care test for detecting colorectal cancer. These results warrant further development by increasing the size of the study with a device specifically designed for colorectal cancer.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Efficacy of a real time optoelectronic device (TruScreen™) in detecting cervical intraepithelial pathologies: a prospective observational study

OBJECTIVE

To assess the effect of TruScreen™ (an objective optoelectronic cervical screening device) in improving the sensitivity of cervical screening programs either alone or in combination with Papanicolaou (PAP) smear or human papilloma virus (HPV) DNA screening.

MATERIAL AND METHODS

Our study was performed in 285 patients with abnormal Pap test results. TruScreen™ and HPV screening methods were performed in all participants. Consistency and differences between the tests were compared with cervical biopsy results.

RESULTS

TruScreen™ was found to be an approach method in the determination of cervical pathologies (ROC curve area underlined=0.606) and with an 89.5% negative predictive value. HPV screening remains a counterpart to TruScreen™ with a 0.620 area underlined in the ROC curve and an 83% negative predictive value.

CONCLUSION

As determined in our study, TruScreen™ with a sensitivity of 86.1% can be used as a screening test with instant and not professional dependent results for cervical cancer screening. Avoiding from subjectivity in interpretation of Pap smears and requirement for pathologists, TruScreen™ can be a used for cervical cancer screening especially in countries with a low socio-economic status. The combination of TruScreen™ and HPV screening was not able to demonstrate a significant rise of effectiveness in screening.

Novel advancements in colposcopy: historical perspectives and a systematic review of future developments

OBJECTIVE

To describe novel innovations and techniques for the detection of high-grade dysplasia.

MATERIALS AND METHODS

Studies were identified through the PubMed database, spanning the last 10 years. The key words (["computerized colposcopy" or "digital colposcopy" or "spectroscopy" or "multispectral digital colposcopy" or "dynamic spectral imaging", or "electrical impedance spectroscopy" or "confocal endomicroscopy" or "confocal microscopy"or "optical coherence tomography"] and ["cervical dysplasia" or cervical precancer" or "cervix" or "cervical"]) were used. The inclusion criteria were published articles of original research referring to noncolposcopic evaluation of the cervix for the detection of cervical dysplasia. Only English-language articles from the past 10 years were included, in which the technologies were used in vivo, and sensitivities and specificities could be calculated.

RESULTS

The single author reviewed the articles for inclusion. Primary search of the database yielded 59 articles, and secondary cross-reference yielded 12 articles. Thirty-two articles met the inclusion criteria.

CONCLUSIONS

An instrument that globally assesses the cervix, such as computer-assisted colposcopy, optical spectroscopy, and dynamic spectral imaging, would provided the most comprehensive estimate of disease and is therefore best suited when treatment is preferred. Electrical impedance spectroscopy, confocal microscopy, and optical coherence tomography provide information at the cellular level to estimate histology and are therefore best suited when deferment of treatment is preferred. If a device is to eventually replace the colposcope, it will likely combine technologies to best meet the needs of the target population, and as such, no single instrument may prove to be universally appropriate. Analyses of false-positive rates, additional colposcopies and biopsies, cost, and absolute life-savings will be important when considering these technologies and are limited thus far.

Integrated cervical smear screening using liquid based cytology and bioimpedance analysis

OBJECTIVE

To minimize the false negativity in cervical cancer screening with Papanicolaou (Pap) test, there is a need to explore novel cytological technique and identification of unique and important cellular features from the perspectives of morphological as well as biophysical properties.

MATERIALS AND METHODS

The present study explores the feasibility of low-cost cervical monolayer techniques in extracting cyto-pathological features to classify normal and abnormal conditions. The cervical cells were also analyzed in respect to their electrical bioimpedance.

RESULT

The results show that newly developed monolayer technique for cervical smears is cost effective, capable of cyto-pathological evaluation. Electrical bioimpedance study evidenced distinction between abnormal and normal cell population at more than two order of magnitude difference.

CONCLUSION

The integration of bioimpedance observation along with the proposed low-cost monolayer technology could increase the efficiency of the cervical screening to a greater extent thereby reducing the rates of faulty diagnosis.

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

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

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Toward microendoscopic electrical impedance tomography for intraoperative surgical margin assessment

No clinical protocols are routinely used to intraoperatively assess surgical margin status during prostate surgery. Instead, margins are evaluated through pathological assessment of the prostate following radical prostatectomy, when it is too late to provide additional surgical intervention. An intraoperative device potentially capable of assessing surgical margin status based on the electrical property contrast between benign and malignant prostate tissue has been developed. Specifically, a microendoscopic electrical impedance tomography (EIT) probe has been constructed to sense and image, at near millimeter resolution, the conductivity contrast within heterogeneous biological tissues with the goal of providing surgeons with real-time assessment of margin pathologies. This device consists of a ring of eight 0.6-mm diameter electrodes embedded in a 5-mm diameter probe tip to enable access through a 12-mm laparoscopic port. Experiments were performed to evaluate the volume of tissue sensed by the probe. The probe was also tested with inclusions in gelatin, as well as on a sample of porcine tissue with clearly defined regions of adipose and muscle. The probe's area of sensitivity consists of a circular area of 9.1 mm(2) and the maximum depth of sensitivity is approximately 1.5 mm. The probe is able to distinguish between high contrast muscle and adipose tissue on a sub-mm scale (∼500 μm). These preliminary results suggest that EIT is possible in a probe designed to fit within a 12-mm laparoscopic access port.

Classification of breast tumour using electrical impedance and machine learning techniques

When a breast lump is detected through palpation, mammography or ultrasonography, the final test for characterization of the tumour, whether it is malignant or benign, is biopsy. This is invasive and carries hazards associated with any surgical procedures. The present work was undertaken to study the feasibility for such characterization using non-invasive electrical impedance measurements and machine learning techniques. Because of changes in cell morphology of malignant and benign tumours, changes are expected in impedance at a fixed frequency, and versus frequency of measurement. Tetrapolar impedance measurement (TPIM) using four electrodes at the corners of a square region of sides 4 cm was used for zone localization. Data of impedance in two orthogonal directions, measured at 5 and 200 kHz from 19 subjects, and their respective slopes with frequency were subjected to machine learning procedures through the use of feature plots. These patients had single or multiple tumours of various types in one or both breasts, and four of them had malignant tumours, as diagnosed by core biopsy. Although size and depth of the tumours are expected to affect the measurements, this preliminary work ignored these effects. Selecting 12 features from the above measurements, feature plots were drawn for the 19 patients, which displayed considerable overlap between malignant and benign cases. However, based on observed qualitative trend of the measured values, when all the feature values were divided by respective ages, the two types of tumours separated out reasonably well. Using K-NN classification method the results obtained are, positive prediction value: 60%, negative prediction value: 93%, sensitivity: 75%, specificity: 87% and efficacy: 84%, which are very good for such a test on a small sample size. Study on a larger sample is expected to give confidence in this technique, and further improvement of the technique may have the ability to replace biopsy.

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.

Adjunctive colposcopy technologies for examination of the uterine cervix--DySIS, LuViva Advanced Cervical Scan and Niris Imaging System: a systematic review and economic evaluation

BACKGROUND

Women in England (aged 25-64 years) are invited for cervical screening every 3-5 years to assess for cervical intraepithelial neoplasia (CIN) or cancer. CIN is a term describing abnormal changes in the cells of the cervix, ranging from CIN1 to CIN3, which is precancerous. Colposcopy is used to visualise the cervix. Three adjunctive colposcopy technologies for examination of the cervix have been included in this assessment: Dynamic Spectral Imaging System (DySIS), the LuViva Advanced Cervical Scan and the Niris Imaging System.

OBJECTIVE

To determine the clinical effectiveness and cost-effectiveness of adjunctive colposcopy technologies for examination of the uterine cervix for patients referred for colposcopy through the NHS Cervical Screening Programme.

DATA SOURCES

Sixteen electronic databases [Allied and Complementary Medicine Database (AMED), BIOSIS Previews, Cochrane Database of Systematic Reviews (CDSR), Cochrane Central Register of Controlled Trials (CENTRAL), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Database of Abstracts of Reviews of Effects (DARE), EMBASE, Health Management Information Consortium (HMIC), Health Technology Assessment (HTA) database; Inspec, Inside Conferences, MEDLINE, NHS Economic Evaluation Database (NHS EED), PASCAL, Science Citation Index Expanded (SCIE) and Science Citation Index (SCI) - Conference Proceedings], and two clinical trial registries [ClinicalTrials.gov and Current Controlled Trials (CCT)] were searched to September-October 2011.

REVIEW METHODS

Studies comparing DySIS, LuViva or Niris with conventional colposcopy were sought; a narrative synthesis was undertaken. A decision-analytic model was developed, which measured outcomes in terms of quality-adjusted life-years (QALYs) and costs were evaluated from the perspective of the NHS and Personal Social Services with a time horizon of 50 years.

RESULTS

Six studies were included: two studies of DySIS, one study of LuViva and three studies of Niris. The DySIS studies were well reported and had a low risk of bias; they found higher sensitivity with DySIS (both the DySISmap alone and in combination with colposcopy) than colposcopy alone for identifying CIN2+ disease, although specificity was lower with DySIS. The studies of LuViva and Niris were poorly reported and had limitations, which indicated that their results were subject to a high risk of bias; the results of these studies cannot be considered reliable. The base-case cost-effectiveness analysis suggests that both DySIS treatment options are less costly and more effective than colposcopy alone in the overall weighted population; these results were robust to the ranges tested in the sensitivity analysis. DySISmap alone was more costly and more effective in several of the referral groups but the incremental cost-effectiveness ratio (ICER) was never higher than £1687 per QALY. DySIS plus colposcopy was less costly and more effective in all reasons for referral. Only indicative analyses were carried out on Niris and LuViva and no conclusions could be made on their cost-effectiveness.

LIMITATIONS

The assessment is limited by the available evidence on the new technologies, natural history of the disease area and current treatment patterns.

CONCLUSIONS

DySIS, particularly in combination with colposcopy, has higher sensitivity than colposcopy alone. There is no reliable evidence on the clinical effectiveness of LuViva and Niris. DySIS plus colposcopy appears to be less costly and more effective than both the DySISmap alone and colposcopy alone; these results were robust to the sensitivity analyses undertaken. Given the lack of reliable evidence on LuViva and Niris, no conclusions on their potential cost-effectiveness can be drawn. There is some uncertainty about how generalisable these findings will be to the population of women referred for colposcopy in the future, owing to the introduction of the human papillomavirus (HPV) triage test and uptake of the HPV vaccine.

Accuracy of detection of high-grade cervical intraepithelial neoplasia using electrical impedance spectroscopy with colposcopy

Objective

To determine if electrical impedance spectroscopy (EIS) improves the diagnostic accuracy of colposcopy when used as an adjunct.

Design

Prospective, comparative, multi-centre clinical study.

Setting

Three colposcopy clinics: two in England and one in Ireland.

Population

Women referred with abnormal cytology.

Methods

In phase 1, EIS was assessed against colposcopic impression and histopathology of the biopsies taken. In phase 2, a probability index and cut-off value for the detection of high-grade cervical intraepithelial neoplasia (HG–CIN, i.e. grade CIN2+) was derived to indicate sites for biopsy. EIS data collection and analyses were performed in real time and blinded to the clinician. The phase-2 data were analysed using different cut-off values to assess performance of EIS as an adjunct.

Main outcome measure

Histologically confirmed HG–CIN (CIN2+).

Results

A total of 474 women were recruited: 214 were eligible for analysis in phase 1, and 215 were eligible in phase 2. The average age was 33.2 years (median age 30.3 years, range 20–64 years) and 48.5% (208/429) had high-grade cytology. Using the cut-off from phase 1 the accuracy of colposcopic impression to detect HG–CIN when using EIS as an adjunct at the time of examination improved the positive predictive value (PPV) from 78.1% (95% CI 67.5–86.4) to 91.5%. Specificity was also increased from 83.5% (95% CI 75.2–89.9) to 95.4%, but sensitivity was significantly reduced from 73.6% (95% CI 63.0–82.5) to 62.1%, and the negative predictive value (NPV) was unchanged. The positive likelihood ratio for colposcopic impression alone was 4.46. This increased to 13.5 when EIS was used as an adjunct. The overall accuracy of colposcopy when used with EIS as an adjunct was assessed by varying the cut-off applied to a combined test index. Using a cut-off set to give the same sensitivity as colposcopy in phase 2, EIS increased the PPV to detect HG–CIN from 53.5% (95% CI 45.0–61.8) to 67%, and specificity increased from 38.5% (95% CI 29.4–48.3) to 65.1%. NPV was not significantly increased. Alternatively, applying a cut-off to give the same specificity as colposcopy alone increased EIS sensitivity from 88.5% (95% CI 79.9–94.4) to 96.6%, and NPV from 80.8% (95% CI 67.5–90.4) to 93.3%. PPV was not significantly increased. The receiver operator characteristic (ROC) to detect HG–CIN had an area under the curve (AUC) of 0.887 (95% CI 0.840–0.934).

Conclusions

EIS used as an adjunct to colposcopy improves colposcopic performance. The addition of EIS could lead to more appropriate patient management with lower intervention rates.

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.

Application of TruScreen in detecting ASCUS patients

OBJECTIVE

To explore the application of cervical cancer screening system, TruScreen in detecting atypical squamous cell of undetermined significance (ASCUS) patients.

METHODS

A total of 42 cases were selected, who were diagnosed as ASCUS by thinprep cytologic test (TCT). Area from site 15 to 20, site 21 to 32 were detected by TruScreen. And the result was compared with those of cases which had positive pathological result of cervical biopsy.

RESULTS

There were 16 cases with abnormal pathological result in ASCUS cases, including 6 cases with cervical intraepithelial neoplasia (CIN) I, 6 cases with CIN II, 3 cases with CIN III and 1 case with infiltrating carcinoma. The consistency between TCT and pathological test was 38.10% (16/42). The positive rate of TruScreen at site 15-20 was 61.91% (26/42). There was significant difference in consistency with pathological test between TCT and TruScreen (x(2)=4.762, P=0.029). The positive rate of TruScreen at site 21-32 was 66.67% (28/42)(Kappa=0.181, P=0.016). There was significant difference in consistency with pathological test between TCT and TruScreen (x(2)=9.4919, P=0.002). And no case was missed when site 21-32 of patients with CINII and above were detected by TruScreen.

CONCLUSIONS

TruScreen is effective in detecting ASCUS patients.

Bioimpedance spectroscopy: a new tool to assess early esophageal changes linked to gastroesophageal reflux disease?

Bioimpedance spectroscopy can identify pathological changes related to precancerous lesions of the cervix uteri and esophagus. It therefore has the potential to detect early reflux-related changes in the esophageal mucosa, such as dilated intercellular spaces. The reliable detection of dilated intercellular spaces at the time of endoscopy would yield a significant diagnostic advantage for separating patients with functional heartburn from the large proportion of patients with gastroesophageal reflux symptoms but no macroscopic esophagitis or pathological acid exposure. The bioimpedance of the esophageal mucosa, measured with a small caliber probe, was evaluated in a series of preclinical experiments. First, sections of rabbit esophageal epithelium were mounted in Ussing chambers and exposed to solutions at pH 7.4 or pH 1.5 for 45 minutes. Impedance measurements were taken at varying probe pressures. Second, rabbit esophageal epithelia were perfused for 45 minutes in situ with pH 1.1 or control solutions and impedance measurements taken. Samples from both in vitro and in situ experiments were taken for morphological examination by light microscopy. Finally, esophageal bioimpedance was measured in awake dogs with permanent esophagocutaneous stoma. The in situ experiments demonstrated that morphological changes in the esophageal mucosa could be discerned by the use of bioimpedance spectroscopy. The variability in resistivity was species-independent but was affected by the pressure applied to the probe. The results suggest that evaluation of bioimpedance spectroscopy for use in a clinical setting is warranted. Small morphological differences in the esophageal mucosa may be detected by the use of bioimpedance spectroscopy.

New technologies and advances in colposcopic assessment

To have a good grasp of clinical colposcopy, it is necessary to understand the histopathologic structure of the normal and dysplastic cervical epithelium. Previous meta-analyses had indicated high overall sensitivity of colposcopy in detecting dysplastic lesions, but recent studies have suggested that the technique has much lower sensitivity in detecting high-grade intraepithelial neoplasia. The best practice in colposcopy relies on accurately taking a biopsy from the correct (i.e. most morphological abnormal) site, and by taking more than one biopsy, the sensitivity for detection of high-grade cervical intraepithelial neoplasia can be increased. Cytological screening programmes of proven and maintained high quality will enhance the predictive colposcopic accuracy for high-grade cervical intraepithelial neoplasia after referral. With the advent of computerised colposcopy and the Internet, digital imaging can be transmitted in real-time for instant viewing, facilitating distant consultation and education. This form of 'telemedicine' will allow family practice and remote areas to have access to colposcopy expertise. Of all the currently available technological adjuncts to colposcopy, spectroscopy devices have demonstrated relatively high sensitivities, and seem to have the best potential to become the technique of choice in future routine clinical practice in developed countries following the human papillomavirus vaccination. Other alternatives may need to be used in parts of the globe with high disease incidence and without organised screening or vaccination programmes. Opportunities remain for global collaboration in research, education and training to promote more effective and affordable cervical screening, and to enhance the skills of colposcopists worldwide.

A preliminary study of the use of bioimpedance in the screening of squamous tongue cancer

Oral cancers are the 11th most common malignancy reported worldwide, accounting for 3% of all newly diagnosed cancer cases, and one with high mortality ratios among all malignancies. The objective of this study was to study the electrical properties of cancerous tongue tissue (CTT) and normal tongue tissue (NTT). Five tongue cancer patients participated in this study. A disposable probe incorporating four silver electrodes was used to measure the electrical properties of CTT and the surrounding NTT of patients. Measurements were performed at six frequencies: 20 Hz; 50 kHz; 1.3 MHz; 2.5 MHz; 3.7 MHz; and 5 MHz, with the amplitude of the applied voltage limited to 200mV. Four measurement parameters of impedance (Z), phase angle (θ), real part of impedance (R), and imaginary part of impedance (X) of tongue tissue were assessed to see if there was any significant difference in the values obtained in CTT and surrounding NTT. The intraclass correlation coefficient showed that all measurements were reliable. A significant difference (P < 0.05 for the four measurement parameters) was found at 50kHz between CTT and surrounding NTT. It was also found that Z and R of CTT were generally smaller than that of surrounding NTT. In conclusion, bioimpedance at a particular frequency is a potentially promising technique for tongue cancer screening.

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

Oral cancers are the 11th most common malignancy reported worldwide, accounting for 3% of all newly diagnosed cancer cases, and one with high mortality ratios among all malignancies. The objectives of this study were therefore to study the electrical properties of cancerous tongue tissue and normal tongue tissue, as well as to investigate a new approach for low-cost, noninvasive, and real-time screening of oral cancer. Twelve tongue cancer patients and twelve healthy subjects participated in this study. A disposable probe with four silver electrodes was used to measure the electrical properties of patient's and healthy subject's tongue tissues at six different frequencies, which were 20Hz, 50kHz, 1.3MHz, 2.5MHz, 3.7MHz and 5MHz. The amplitude of the applied voltage was limited to 200mV. Four measurement parameters of impedance, phase angle, real part of impedance, and imaginary part of impedance of tongue were assessed to see if significant difference in values obtained in patient's and healthy subject's tongue tissues existed. Intraclass correlation coefficient showed that all measurements had good reliability and validity (ICC>0.95 for all measurements). Significant differences were found at 20Hz (p<0.05-0.001 for the four measurement parameters) and 50kHz (p<0.001 for the four measurement parameters) between patient's and healthy subject's tongue tissues. In conclusion, bioimpedance at a particular frequency is a potentially promising technique for tongue cancer screening.

Electrical properties of prostatic tissues: II. Spectral admittivity properties

PURPOSE

The electrical properties of prostate tissues gauged at discrete frequencies provide sufficient contrast to discriminate malignant from benign prostatic tissues. The frequency dependence of these properties is also a function of tissue morphology. We evaluated the potential of this spectral dependence to provide additional diagnostic information for prostate cancer detection.

MATERIALS AND METHODS

Electrical conductivity and permittivity were recorded from 50 ex vivo prostates at 31 logarithmically spaced frequencies of 100 Hz to 100 kHz. We used a well established, 4 parameter (sigma(infinity), Delta sigma, f(c) and alpha) model to describe individual spectra with each model parameter influenced by tissue morphology. We evaluated these parameters in terms of discriminatory power using ROC curves.

RESULTS

Of the 4 spectral parameters sigma(infinity) and f(c) were significantly greater in cancer than in benign tissues and Delta sigma was significantly more negative in cancer than in benign tissues (each p <0.0001). f(c) provided the maximum discriminating power with an ROC AUC of 0.821 and 81.5% specificity at 70% sensitivity. Also, sigma(infinity) and Delta sigma provided high levels of discrimination with an AUC of 0.770 and 0.782, respectively.

CONCLUSIONS

Spectral electrical admittivity properties provide sufficient levels of ex vivo cancer discrimination that may potentially enhance disease localization when prostate cancer is suspected. The development of novel technologies gauging these properties in vivo has the potential to provide new tissue characterizing tools for prostate cancer detection and identification.

The diagnostic accuracy of colposcopy in previously treated cervical intraepithelial neoplasia

OBJECTIVE

To determine whether colposcopy is reliable in diagnosing cervical intraepithelial neoplasia in women who have undergone a previous cervical excision biopsy.

MATERIALS AND METHODS

A prospective study of women attending the colposcopy clinic at the University Hospital of North Staffordshire was performed between January 1998 and December 1999.

RESULTS

A clear histological diagnosis of the grade of cervical intraepithelial neoplasia was available for 469 in the treatment-naive group and 58 in the treatment group. kappa coefficients comparing the colposcopic impression (negative, low-grade, high-grade, or invasion) with histological diagnosis showed that there was no difference between the treatment-naive group, weighted kappa=0.46, and the previous treatment group, weighted kappa=0.47. The sensitivity, specificity, positive predictive value, and negative predictive value of colposcopy for any cervical disease in the treatment-naive women were 93.9%, 51.9%, 96.7%, and 34.1%, respectively, compared with 77.6%, 66.7%, 86.4%, and 35.3% in previously treated women. The sensitivity of colposcopy fell when it was used to differentiate normal and low-grade disease from high-grade disease and invasion: 82.4%, 55.9%, 82.6%, and 49.6% for treatment-naive women, compared with 61.5%, 84.2%, 60.0% and 51.6%, respectively, for the previous treatment group.

CONCLUSIONS

Previous treatment to the cervix does not seem to impair the ability of colposcopy to differentiate normal cervix from all grades of cervical abnormality in women where the squamocolumnar junction is visible. However, there is a suggestion that the sensitivity of colposcopy to differentiate negative/low-grade disease from high-grade disease/invasion is lower in previously treated women.

Advances in the imaging and detection of cervical intra-epithelial neoplasia

Screening for preinvasive disease of the cervix, and detecting and mapping the lesions for treatment, are fundamental to programs for the prevention of cervical cancer. These will become even more important in women vaccinated against humanpapilloma viruses 16 and 18. Biophysical imaging technologies have considerable potential advantages in both screening for and mapping the lesions. This review describes the technologies that seem to have the greatest promise.

Digital colposcopy: ready for use? An overview of literature

The aims of this review were to summarise the various methods of digital colposcopy and to provide an overview of their efficacy. We conducted a literature search and focused on papers that described a technique for colposcopy, other than conventional colposcopy, and compared this with conventional colposcopy and/or histology and included digitalisation of the process. All papers have been classified in one of the following categories: digital imaging and telecolposcopy, spectroscopy, computerised colposcopy, optical coherence tomography and confocal microcolposcopy. Among the most promising developments is spectroscopy, allowing a more or less automated analysis and interpretation of the colposcopic image.

Electrical impedance spectroscopy of benign and malignant prostatic tissues

PURPOSE

The specificity of current screening methods for prostate cancer is limited and it results in approximately 75% to 80% of patients who undergo biopsy having findings negative for cancer. We used electrical impedance spectroscopy to evaluate how significantly the electrical properties of benign and malignant prostatic tissues differ with the goal of providing clinicians with a new biomarker to aid in diagnosis.

MATERIALS AND METHODS

We collected freshly excised prostates from 14 men immediately following radical prostatectomy. The prostates were sectioned into 3 mm slices. Electrical property measurements of conductivity and relative permittivity were recorded from each slice using a coaxially configured probe over the frequency range of 1 kHz to 1 MHz. The area probed was marked so that following tissue fixation and slide preparation histological assessment could be correlated directly with the recorded electrical impedance spectroscopy spectra.

RESULTS

Prostatic adenocarcinoma, benign prostatic hyperplasia, nonhyperplastic glandular tissue and stroma were the primary tissue types probed with electrical impedance spectroscopy. Conductivity ranged from 0.093 S/m at 1 kHz to 0.277 S/m at 1 MHz. Relative permittivity ranged from 8.5 x 10(5) at 1 kHz down to 1.3 x 10(3) at 1 MHz. There were significant conductivity differences between cancer and stroma at all frequencies (p <0.01). There were significant permittivity differences between cancer and benign prostatic hyperplasia at frequencies greater that 92 kHz (p <0.01). Significant correlations were observed between electrical properties, and the concentration of stromal and glandular tissues present in the tissue area histologically assessed.

CONCLUSIONS

The electrical properties of benign and malignant prostate tissues differ significantly. This should be considered for use as a diagnostic tool. The differences observed between cancer and benign prostatic hyperplasia are especially important since current screening methods do not reliably differentiate between the 2 conditions.

Impedance measurements for cervical cancer diagnosis

This article discusses using impedance measurements of body tissue in a diagnostic device. It then reviews the theory behind using these measurements to separate normal from diseased tissue. A small amount of time is devoted to discussing the meaning of sensitivity, specificity, and the receiver operating characteristic (ROC) curve, and their meanings. It also discusses the prospects of some new clinical devices using impedance measurements. One of the devices it focuses on is the TruScreen probe made by the Australian firm, Polartechnics.