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Yoshida K. Bioengineering and the cervix: The past, current, and future for addressing preterm birth. Curr Res Physiol 2023; 6:100107. [PMID: 38107784 PMCID: PMC10724223 DOI: 10.1016/j.crphys.2023.100107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/23/2023] [Accepted: 09/20/2023] [Indexed: 12/19/2023] Open
Abstract
The uterine cervix plays two important but opposing roles during pregnancy - as a mechanical barrier that maintains the fetus for nine months and as a compliant structure that dilates to allow for the delivery of a baby. In some pregnancies, however, the cervix softens and dilates prematurely, leading to preterm birth. Bioengineers have addressed and continue to address the lack of reduction in preterm birth rates by developing novel technologies to diagnose, prevent, and understand premature cervical remodeling. This article highlights these existing and emerging technologies and concludes with open areas of research related to the cervix and preterm birth that bioengineers are currently well-positioned to address.
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Affiliation(s)
- Kyoko Yoshida
- Department of Biomedical Engineering, University of Minnesota, 7-105 Nils Hasselmo Hall, 312 Church Street SE, Minneapolis, MN, 55455, USA
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Choi H, Barker E, Abduljabar AA, Anumba D, Porch A. Cervical Tissue Hydration Level Monitoring by a Resonant Microwave Coaxial Probe. SENSORS (BASEL, SWITZERLAND) 2022; 22:9527. [PMID: 36502229 PMCID: PMC9738423 DOI: 10.3390/s22239527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 11/24/2022] [Accepted: 11/29/2022] [Indexed: 06/17/2023]
Abstract
Cervical tissue hydration level is one of the most important parameters to monitor in the early diagnosis of preterm birth. Electrical-impedance-spectroscopy-based techniques are often used, but they suffer from limited accuracy. Open microwave coaxial probes have been widely used as a broadband dielectric characterization technique for human tissue samples due to their versatility, but with limited accuracy due to their nonresonant nature. In this work, a resonant microwave open coaxial probe with multiple harmonic resonances is proposed as a sensing platform for tissue-hydration-level monitoring. The mechanical design was analyzed and verified by finite-element full 3D electromagnetic simulation and experiments. Dominant sources of errors and the ways to mitigate them were discussed. In vitro experiments were carried out on human cervix samples to verify the precision and accuracy by comparing the results to a commercial skin-hydration sensor. The proposed sensor shows mean fractional frequency shift of (3.3 ± 0.3) × 10-4 per unit % over the entire data. This translates into an absolute frequency shift (ΔfN) of 252 ± 23 kHz/%, 455 ± 41 kHz/%, and 647 ± 57 kHz/% at second, fourth, and sixth harmonic resonance, respectively.
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Affiliation(s)
- Heungjae Choi
- School of Engineering, Cardiff University, 14-17 The Parade, Cardiff CF24 3AA, UK
| | - Emilia Barker
- School of Clinical Dentistry, University of Sheffield, 19 Claremont Crescent, Sheffield S10 2TA, UK
| | | | - Dilly Anumba
- Department of Oncology and Metabolism, JW4/40, Level 4, Jessop Wing, Tree Root Walk, Sheffield S10 2SF, UK
| | - Adrian Porch
- School of Engineering, Cardiff University, 14-17 The Parade, Cardiff CF24 3AA, UK
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Anumba DOC, Stern V, Healey JT, Dixon S, Brown BH. Value of cervical electrical impedance spectroscopy to predict spontaneous preterm delivery in asymptomatic women: the ECCLIPPx prospective cohort study. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2021; 58:293-302. [PMID: 32798253 DOI: 10.1002/uog.22180] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 07/30/2020] [Accepted: 08/03/2020] [Indexed: 06/11/2023]
Abstract
OBJECTIVES Preterm birth (PTB) accounts for two-thirds of deaths of structurally normal babies and is associated with substantial lifetime healthcare costs. Prevention of PTB remains limited by the modest accuracy of prediction methods, namely transvaginal ultrasound (TVS) cervical length (CL) measurement and quantitative cervicovaginal fetal fibronectin (FFN) estimation. We report the first substantive study detailing the predictive performance of a cervical probe device based on electrical impedance spectroscopy (EIS) for PTB - the EleCtriCaL Impedance Prediction of Preterm birth by spectroscopy of the cervix (ECCLIPPx) study. We aimed to compare the accuracy of cervical EIS-based prediction of spontaneous PTB with that of prediction using TVS-CL and FFN in asymptomatic women in the mid-trimester. METHODS We studied asymptomatic women with a singleton pregnancy at 20-22 weeks' and 26-28 weeks' gestation. EIS was performed using a Sheffield Mark 5.0 device that makes measurements in the frequency range 76 Hz to 625 kHz using a small probe housing tetrapolar electrodes. TVS-CL and FFN were also measured. The associations of cervical EIS, TVS-CL and FFN with spontaneous delivery before 37 weeks and before 32 weeks were determined by multivariate linear and non-linear logistic regression analysis. Areas under the receiver-operating-characteristics curves (AUC) plots of sensitivity against specificity were used to compare the predictive performance of all parameters, both in isolation and in combination. RESULTS Of the 365 asymptomatic women studied at 20-22 weeks who were not receiving treatment, 29 had spontaneous PTB, 14 had indicated PTB and 322 had term birth. At the higher frequencies assessed, cervical EIS predicted spontaneous PTB before 37 weeks with an AUC of 0.76 (95% CI, 0.71-0.81), compared with AUCs of 0.72 (95% CI, 0.66-0.76) for TVS-CL and 0.62 (95% CI, 0.56-0.72) for FFN. Combining all three assessments improved the prediction of spontaneous PTB before 37 weeks (AUC, 0.79 (95% CI, 0.74-0.83)) compared with TVS-CL and FFN alone. Incorporating a history of spontaneous PTB (defined as previous mid-trimester miscarriage or spontaneous PTB (14 to < 37 weeks)) into the cervical EIS prediction model improved the accuracy of prediction of spontaneous PTB before 37 weeks (AUC, 0.83 (95% CI, 0.78-0.87)) and before 32 weeks (AUC, 0.86 (95% CI, 0.82-0.90)). CONCLUSIONS Mid-trimester cervical EIS assessment predicts spontaneous PTB. Larger confirmatory studies investigating its potential clinical utility and to inform effective preventive interventions are required. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.
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Affiliation(s)
- D O C Anumba
- Academic Unit of Reproductive and Developmental Medicine, Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
| | - V Stern
- Academic Unit of Reproductive and Developmental Medicine, Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
| | - J T Healey
- Medical Physics and Clinical Engineering, University of Sheffield, Sheffield, UK
| | - S Dixon
- School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
| | - B H Brown
- Medical Physics and Clinical Engineering, University of Sheffield, Sheffield, UK
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Andreasen N, Crandall H, Brimhall O, Miller B, Perez-Tamayo J, Martinsen OG, Kauwe SK, Sanchez B. Skin Electrical Resistance as a Diagnostic and Therapeutic Biomarker of Breast Cancer Measuring Lymphatic Regions. IEEE ACCESS : PRACTICAL INNOVATIONS, OPEN SOLUTIONS 2021; 9:152322-152332. [PMID: 34888126 PMCID: PMC8654262 DOI: 10.1109/access.2021.3123569] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Skin changes associated with alterations in the interstitial matrix and lymph system might provide significant and measurable effects due to the presence of breast cancer. This study aimed to determine if skin electrical resistance changes could serve as a diagnostic and therapeutic biomarker associated with physiological changes in patients with malignant versus benign breast cancer lesions. Forty-eight women (24 with malignant cancer, 23 with benign lesions) were enrolled in this study. Repeated skin resistance measurements were performed within the same session and 1 week after the first measurement in the breast lymphatic region and non-breast lymphathic regions. Intraclass correlation coefficients were calculated to determine the technique's intrasession and intersession reproducibility. Data were then normalized as a mean of comparing cross-sectional differences between malignant and benign lesions of the breast. Six months longitudinal data from six patients that received therapy were analyzed to detect the effect of therapy. Standard descriptive statistics were used to compare ratiometric differences between groups. Skin resistance data were used to train a machine learning random forest classification algorithm to diagnose breast cancer lesions. Significant differences between malignant and benign breast lesions were obtained (p<0.01), also pre- and post-treatment (p<0.05). The diagnostic algorithm demonstrated the capability to classify breast cancer with an area under the curve of 0.68, sensitivity of 66.3%, specificity of 78.5%, positive predictive value 70.7% and negative predictive value 75.1%. Measurement of skin resistance in patients with breast cancer may serve as a convenient screening tool for breast cancer and evaluation of therapy. Further work is warranted to improve our approach and further investigate the biophysical mechanisms leading to the observed changes.
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Affiliation(s)
| | - Henry Crandall
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | | | - Brittny Miller
- Ogden Regional Medical Center, Department of Women's Imaging, Ogden, UT 84405, USA
| | - Jose Perez-Tamayo
- Ogden Regional Medical Center, Department of Women's Imaging, Ogden, UT 84405, USA
| | - Orjan G Martinsen
- Department of Physics, University of Oslo, 0371 Oslo, Norway
- Department of Clinical and Biomedical Engineering, Oslo University Hospital, 0372 Oslo, Norway
| | - Steven K Kauwe
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | - Benjamin Sanchez
- Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112, USA
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Yao X, Li D, Park HC, Chen D, Guan H, Mahendroo M, Li X. Ultra-sensitive optical coherence elastography using a high-dynamic-range force loading scheme for cervical rigidity assessment. BIOMEDICAL OPTICS EXPRESS 2020; 11:688-698. [PMID: 32133219 PMCID: PMC7041475 DOI: 10.1364/boe.383720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 12/16/2019] [Accepted: 12/22/2019] [Indexed: 05/29/2023]
Abstract
An ultra-sensitive, wide-range force loading scheme is proposed for compression optical coherence elastography (OCE) that allows for the quantitative analysis of cervical tissue elasticity ex vivo. We designed a force loading apparatus featuring a water sink for minuscule incremental loading through a volume-controlled water droplet, from which the Young's modulus can be calculated by fitting the stress-strain curve. We validated the performance of the proposed OCE system on homogenous agar phantoms, showing the Young's modulus can be accurately estimated using this scheme. We then measured the Young's modulus of rodent cervical tissues acquired at different gestational ages, showing that the cervical rigidity of rodents was significantly dropped when entering the third trimester of pregnancy.
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Affiliation(s)
- Xinwen Yao
- Department of Biomedical Engineering, 720 Rutland Ave, Baltimore, MD 21205, USA
- SERI-NTU Advanced Ocular Engineering (STANCE), 50 Nanyang Drive #04-13, Singapore 637553, Singapore
- These authors contribute equally to this work
| | - Dawei Li
- Department of Biomedical Engineering, 720 Rutland Ave, Baltimore, MD 21205, USA
- These authors contribute equally to this work
| | - Hyeon-Cheol Park
- Department of Biomedical Engineering, 720 Rutland Ave, Baltimore, MD 21205, USA
| | - Defu Chen
- Department of Biomedical Engineering, 720 Rutland Ave, Baltimore, MD 21205, USA
| | - Honghua Guan
- Department of Biomedical Engineering, 720 Rutland Ave, Baltimore, MD 21205, USA
| | - Mala Mahendroo
- Department of Obstetrics and Gynecology, The University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xingde Li
- Department of Biomedical Engineering, 720 Rutland Ave, Baltimore, MD 21205, USA
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Differentiation Between Normal and Cancerous Human Urothelial Cell Lines Using Micro-Electrical Impedance Spectroscopy at Multiple Frequencies. J Med Biol Eng 2018. [DOI: 10.1007/s40846-018-0426-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Qian X, Jiang Y, Liu L, Shi SQ, Garfield RE, Liu H. Changes in ectocervical surface area in women throughout pregnancy compared to non-pregnant and postpartum states. J Matern Fetal Neonatal Med 2016; 29:3677-81. [PMID: 26864001 DOI: 10.3109/14767058.2016.1140739] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE The objective of this study is to estimate changes in the surface area of the ectocervix (CA) in women during pregnancy and compare this to postpartum and non-pregnant states. METHODS CA was evaluated in 210 normal nulliparous women divided into groups from early to late gestation, 40 postpartum women, and 25 non-pregnant women. CA in cm(2) was estimated from analysis of images taken with an endoscope of the cervical face and an mm scale. An mm scale was also used to determine fornix length and fornix area computed. RESULTS The face, fornix, and total areas of the CA of non-pregnant and postpartum groups are significantly smaller (p < 0.001) than these areas in groups during pregnancy. Generally, the CA of the face, fornix, and total area are also less in early pregnancy compared with late gestation (p < 0.01 to <0.001). Total CA correlates with gestational age (r = 0.196, p < 0.004). CONCLUSIONS (1) During pregnancy, CA slowly and progressively increases to >75% area compared with CA of non-pregnant patients and then reverts back to low CA postpartum. (2) Increases in CA during pregnancy occur in both the face and fornix areas. (3) Increases in CA reflect enlargement in cervical volume and remodeling during pregnancy.
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Affiliation(s)
- Xueya Qian
- a Preterm Birth Prevention and Treatment Unit, Department of Obstetrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou , China and.,b Department of Obstetrics , First Affiliated Hospital of Jinan University , Guangzhou , China
| | - Yanmin Jiang
- a Preterm Birth Prevention and Treatment Unit, Department of Obstetrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou , China and
| | - Lei Liu
- a Preterm Birth Prevention and Treatment Unit, Department of Obstetrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou , China and
| | - Shao-Qing Shi
- a Preterm Birth Prevention and Treatment Unit, Department of Obstetrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou , China and
| | - Robert E Garfield
- a Preterm Birth Prevention and Treatment Unit, Department of Obstetrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou , China and
| | - Huishu Liu
- a Preterm Birth Prevention and Treatment Unit, Department of Obstetrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou , China and
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Murdoch C, Brown BH, Hearnden V, Speight PM, D'Apice K, Hegarty AM, Tidy JA, Healey TJ, Highfield PE, Thornhill MH. Use of electrical impedance spectroscopy to detect malignant and potentially malignant oral lesions. Int J Nanomedicine 2014; 9:4521-32. [PMID: 25285005 PMCID: PMC4181751 DOI: 10.2147/ijn.s64087] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
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.
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Affiliation(s)
- Craig Murdoch
- Unit of Oral and Maxillofacial Medicine and Surgery, University of Sheffield School of Clinical Dentistry, Sheffield, United Kingdom
| | - Brian H Brown
- University of Sheffield Medical School, Beech Hill Road, Sheffield, United Kingdom
| | - Vanessa Hearnden
- Unit of Oral and Maxillofacial Medicine and Surgery, University of Sheffield School of Clinical Dentistry, Sheffield, United Kingdom
| | - Paul M Speight
- Unit of Oral and Maxillofacial Pathology, University of Sheffield School of Clinical Dentistry, Sheffield, United Kingdom
| | - Katy D'Apice
- Unit of Oral and Maxillofacial Medicine and Surgery, University of Sheffield School of Clinical Dentistry, Sheffield, United Kingdom ; Unit of Oral Medicine, Charles Clifford Dental Hospital, Sheffield Teaching Hospitals National Health Service Foundation Trust, Sheffield, United Kingdom
| | - Anne M Hegarty
- Unit of Oral Medicine, Charles Clifford Dental Hospital, Sheffield Teaching Hospitals National Health Service Foundation Trust, Sheffield, United Kingdom
| | - John A Tidy
- Department of Gynaecological Oncology, Royal Hallamshire Hospital, Sheffield, United Kingdom
| | - T Jamie Healey
- Department of Medical Physics, Royal Hallamshire Hospital, Sheffield, United Kingdom
| | - Peter E Highfield
- Zilico Ltd., The MedTECH Centre, Rutherford House, Manchester Science Park, Manchester, United Kingdom
| | - Martin H Thornhill
- Unit of Oral and Maxillofacial Medicine and Surgery, University of Sheffield School of Clinical Dentistry, Sheffield, United Kingdom ; Unit of Oral Medicine, Charles Clifford Dental Hospital, Sheffield Teaching Hospitals National Health Service Foundation Trust, Sheffield, United Kingdom
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Mazza E, Parra-Saavedra M, Bajka M, Gratacos E, Nicolaides K, Deprest J. In vivo assessment of the biomechanical properties of the uterine cervix in pregnancy. Prenat Diagn 2014; 34:33-41. [PMID: 24155152 DOI: 10.1002/pd.4260] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Revised: 10/14/2013] [Accepted: 10/17/2013] [Indexed: 02/02/2023]
Abstract
Measuring the stiffness of the cervix might be useful in the prediction of preterm delivery or successful induction of labor. For that purpose, a variety of methods for quantitative determination of physical properties of the pregnant cervix have been developed. Herein, we review studies on the clinical application of these new techniques. They are based on the quantification of mechanical, optical, or electrical properties associated with increased hydration and loss of organization in collagen structure. Quasi-static elastography determines relative values of stiffness; hence, it can identify differences in deformability. Quasi-static elastography unfortunately cannot quantify in absolute terms the stiffness of the cervix. Also, the current clinical studies did not demonstrate the ability to predict the time point of delivery. In contrast, measurement of maximum deformability of the cervix (e.g. quantified with the cervical consistency index) provided meaningful results, showing an increase in compliance with gestational age. These findings are consistent with aspiration measurements on the pregnant ectocervix, indicating a progressive decrease of stiffness along gestation. Cervical consistency index and aspiration measurements therefore represent promising techniques for quantitative assessment of the biomechanical properties of the cervix.
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Etemadi M, Chung P, Heller JA, Liu JA, Rand L, Roy S. Towards BirthAlert--A Clinical Device Intended for Early Preterm Birth Detection. IEEE Trans Biomed Eng 2013; 60:3484-93. [PMID: 23893706 PMCID: PMC4605421 DOI: 10.1109/tbme.2013.2272601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Preterm birth causes 1 million infant deaths worldwide every year, making it the leading cause of infant mortality. Existing diagnostic tests such as transvaginal ultrasound or fetal fibronectin either cannot determine if preterm birth will occur in the future or can only predict the occurrence once cervical shortening has begun, at which point it is too late to reverse the accelerated parturition process. Using iterative and rapid prototyping techniques, we have developed an intravaginal proof-of-concept device that measures both cervical bioimpedance and cervical fluorescence to characterize microstructural changes in a pregnant woman's cervix in hopes of detecting preterm birth before macroscopic changes manifest in the tissue. If successful, such an early alert during this "silent phase" of the preterm birth syndrome may open a new window of opportunity for interventions that may reverse and avoid preterm birth altogether.
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Affiliation(s)
- Mozziyar Etemadi
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158 USA
| | - Philip Chung
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158 USA ()
| | - J. Alex Heller
- University of California, San Francisco, CA 94158 USA, and also with the University of California, Berkeley, CA 94720 USA ()
| | - Jonathan A. Liu
- Keck School of Medicine, University of Southern California, Los Angeles, CA 90089 USA ()
| | - Larry Rand
- Department of Obstetrics and Gynecology and Reproductive Sciences, University of California, San Francisco, CA 94143 USA ()
| | - Shuvo Roy
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158 USA ()
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Wade R, Spackman E, Corbett M, Walker S, Light K, Naik R, Sculpher M, Eastwood A. Adjunctive colposcopy technologies for examination of the uterine cervix--DySIS, LuViva Advanced Cervical Scan and Niris Imaging System: a systematic review and economic evaluation. Health Technol Assess 2013; 17:1-240, v-vi. [PMID: 23449335 PMCID: PMC4781255 DOI: 10.3310/hta17080] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
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.
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Affiliation(s)
- R Wade
- CRD/CHE Technology Assessment Group, Centre for Reviews and Dissemination, University of York, York, UK
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Feltovich H, Hall TJ, Berghella V. Beyond cervical length: emerging technologies for assessing the pregnant cervix. Am J Obstet Gynecol 2012; 207:345-54. [PMID: 22717270 DOI: 10.1016/j.ajog.2012.05.015] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 05/02/2012] [Accepted: 05/21/2012] [Indexed: 12/12/2022]
Abstract
Spontaneous preterm birth is a heterogeneous phenotype. A multitude of pathophysiologic pathways culminate in the final common denominator of cervical softening, shortening, and dilation that leads to preterm birth. A precise description of specific microstructural changes to the cervix is imperative if we are to identify the causative upstream molecular processes and resultant biomechanical events that are associated with each unique pathway. Currently, however, we have no reliable clinical tools for quantitative and objective evaluation, which likely contributes to the reason the singleton spontaneous preterm birth rate has not changed appreciably in >100 years. Fortunately, promising techniques to evaluate tissue hydration, collagen structure, and/or tissue elasticity are emerging. These will add to the body of knowledge about the cervix and facilitate the coordination of molecular studies and ultimately lead to novel approaches to preterm birth prediction and, finally, prevention.
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Yoon K, Lee KW, Kim SB, Han TR, Jung DK, Roh MS, Lee JH. Electrical impedance spectroscopy and diagnosis of tendinitis. Physiol Meas 2009; 31:171-82. [PMID: 20009187 DOI: 10.1088/0967-3334/31/2/004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
There have been a number of studies that investigate the usefulness of bioelectric signals in diagnoses and treatment in the medical field. Tendinitis is a musculoskeletal disorder with a very high rate of occurrence. This study attempts to examine whether electrical impedance spectroscopy (EIS) can detect pathological changes in a tendon and find the exact location of the lesion. Experimental tendinitis was induced by injecting collagenase into one side of the patellar tendons in rabbits, while the other side was used as the control. After measuring the impedance in the tendinitis and intact tendon tissue, the dissipation factor was computed. The real component of impedance and the dissipation factor turned out to be lower in tendinitis than in intact tissues. Moreover, the tendinitis dissipation factor spectrum showed a clear difference from that of the intact tendon, indicating its usefulness as a tool for detecting the location of the lesion. Pathologic findings from the tissues that were obtained after measuring the impedance confirmed the presence of characteristics of tendinitis. In conclusion, EIS is a useful method for diagnosing tendinitis and detecting the lesion location in invasive treatment.
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Affiliation(s)
- Kisung Yoon
- Department of Physical Medicine and Rehabilitation, College of Medicine, Dong-A University, Busan, Korea
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Jokhi RP, Brown BH, Anumba DOC. The role of cervical Electrical Impedance Spectroscopy in the prediction of the course and outcome of induced labour. BMC Pregnancy Childbirth 2009; 9:40. [PMID: 19725953 PMCID: PMC3224746 DOI: 10.1186/1471-2393-9-40] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Accepted: 09/02/2009] [Indexed: 12/03/2022] Open
Abstract
Background Previous work by us and others had suggested that cervical electrical impedance spectroscopy (EIS) may be predictive of the outcome of induced labour. We sought to determine which probe configuration of the EIS device is predictive of the outcome of induced labour and compare this to digital assessment by the Bishop score. Methods In a prospective cohort of 205 women admitted for induction of labour, we used four probes of diameter 3, 6, 9 and 12 mm connected to an impedance meter to measure cervical resistivity (CR) in Ohm.meters at 14 electrical frequencies and compared their values to digital assessment of the cervix by the Bishop score for the prediction of the outcome of induced labour. We tested the association of labour characteristics and outcomes with CR and Bishop score by stepwise multilinear regression analyses, and the accuracy of prediction of categorical clinical outcomes by analysis of the area under the curves (AUC) of derived Receiver Operator Characteristic (ROC) curves. Results Of the four CR probe dimensions studied, only the 12 mm probe was predictive of any labour indices. In the frequency range 19 - 156 kHz, CR obtained with this probe was higher in women who delivered by caesarean section (CS) than those who delivered vaginally, and in labours lasting > 24 hrs. Cervical resistivity at 78.1 kHz best predicted vaginal delivery [optimal cut-off <2.25 Ohm.meter, AUC 0.66 (95% CI 0.59-0.72), sensitivity 71.0%, specificity 56.5%, LR+ 1.63, LR- 0.51, P < 0.01] and labour duration >24 hrs [optimal cut-off 2.27 Ω.m, AUC 0.65 (95% CI 0.58, 0.72), sensitivity 71%, specificity 59%, LR+ 1.72, LR- 0.50, P < 0.05]. In contrast digital assessment by the Bishop score neither predicted vaginal delivery nor the duration of labour. However, Bishop score predicted time to onset of labour > 12 hours and induction-delivery interval < 24 hrs [optimal cut-off ≤ 4, AUC 0.8 (95% CI 0.75, 0.86), sensitivity 77%, specificity 76%, LR+ 3.3, LR- 0.3, P < 0.05] whilst CR did not. Conclusion Cervical resistivity appears predictive of labour duration and delivery mode following induced labour. However the low predictive values obtained suggest that its current design proffers no immediate clinical utility.
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Affiliation(s)
- Roobin P Jokhi
- University of Sheffield, Sheffield Teaching Hospitals NHS Trust, Sheffield, UK.
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15
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O'Connell MP, Avis NJ, Brown BH, Killick SR, Lindow SW. Electrical impedance measurements: an objective measure of prelabor cervical change. J Matern Fetal Neonatal Med 2009; 14:389-91. [PMID: 15061317 DOI: 10.1080/14767050412331312230] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To investigate the use of electrical impedance measurements of the pregnant cervix as an objective measure of cervical favorability (Bishop score > or = 5). METHODS A prospective study of 86 women, investigating electrical impedance measurements of the pregnant cervix at the time of induction of labor. Transfer electrical impedance measurements were made by placing a tetrapolar pencil probe of 8 mm in diameter on the surface of the cervix. A Bishop score was determined simultaneously. RESULTS A mean resistivity (standard error of the mean) of 7.03 (6.01-8.04) omega(m) was measured for the unfavorable group and 5.34 (4.61-6.07) omega(m) for the favorable group. This was a statistically significant difference (p = 0.016). CONCLUSION We highlight the ability of this safe, painless technique to differentiate the favorable from the unfavorable cervix at induction of labor.
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Affiliation(s)
- M P O'Connell
- Coombe Women's Hospital, Dublin, Republic of Ireland
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16
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Jokhi RP, Ghule VV, Brown BH, Anumba DOC. Reproducibility and repeatability of measuring the electrical impedance of the pregnant human cervix-the effect of probe size and applied pressure. Biomed Eng Online 2009; 8:10. [PMID: 19534806 PMCID: PMC2704213 DOI: 10.1186/1475-925x-8-10] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2009] [Accepted: 06/17/2009] [Indexed: 12/20/2022] Open
Abstract
Background The utility of cervical electrical impedance spectroscopy (EIS) as a diagnostic tool is being investigated in clinical trials. We sought to assess the reliability of two different sizes of tetrapolar probes used in measuring cervical impedance. Methods Cervical transfer impedance was measured at 14 frequencies between 76 and 625 000 Hz from 11 pregnant subjects at term. Repeated measurements were taken with two probes (3 mm and 12 mm diameter) applied softly (approximately 0.7 Newton of force), and firmly (approximately 2.2 Newton) to the surface of the cervix by two observers. The intra-class correlation coefficient (ICC), coefficient of variation (CV) and repeatability standard deviations (SD) were derived from these measurements and compared. Results Measurements taken by one observer were highly repeatable for both probes as demonstrated by high ICC and low CV values. Probe performance was improved further by firm application. Firm application of the 3 mm probe resulted in ICC values that ranged from 0.936 to 0.986 (p = 0.0001) and CV values between 1.0 and 3.4%. Firm pressure with the 12 mm probe resulted in ICC values that ranged between 0.914 and 0.988 (p = 0.0001) with CV values between 0.7 and 2.1%. In addition, the repeatability SD was low across all frequencies implying that there was low intra-observer variability. Measurements taken by 2 observers with firm application of the 12 mm probe demonstrated moderate reproducibility between 9.8 and 156 kHz, the frequency range in which previous clinical studies have shown predictive association between high cervical resistivity and vaginal delivery: ICC values ranged between 0.528 and 0.638 (p < 0.05), CV values were between 3.3 and 5.2% and reproducibility SD values were also low. In contrast the 3 mm probe demonstrated poor reproducibility at all study frequencies. Conclusion Measuring cervical resistivity by a single observer with both the 3 and 12 mm probes is highly repeatable whilst inter-observer reproducibility is poor with the 3 mm probe but moderately good when the 12 mm probe is firmly applied to the cervix in the frequency range 9.8 to 156 kHz, consistent with our observations of probe performance in clinical trials.
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Affiliation(s)
- Roobin P Jokhi
- Academic Unit of Reproductive and Developmental Medicine, University of Sheffield and Sheffield Teaching Hospitals NHS Trust, Sheffield, UK.
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17
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Bauer M, Mazza E, Jabareen M, Sultan L, Bajka M, Lang U, Zimmermann R, Holzapfel GA. Assessment of the in vivo biomechanical properties of the human uterine cervix in pregnancy using the aspiration test. Eur J Obstet Gynecol Reprod Biol 2009; 144 Suppl 1:S77-81. [DOI: 10.1016/j.ejogrb.2009.02.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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18
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Schlembach D, Mackay L, Shi L, Maner WL, Garfield RE, Maul H. Cervical ripening and insufficiency: from biochemical and molecular studies to in vivo clinical examination. Eur J Obstet Gynecol Reprod Biol 2009; 144 Suppl 1:S70-6. [PMID: 19303692 DOI: 10.1016/j.ejogrb.2009.02.036] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
To understand cervical ripening and especially the pathophysiology of cervical insufficiency, it is important to know the cervical composition: the cervix is dominated by fibrous connective tissue, consisting predominantly of Type I collagen (70%). Despite many studies of the cervix, we still rely upon relatively crude methods for clinical evaluation of the cervix. If the amount of cervical collagen plays a role in cervical insufficiency and in success of or length of induction of labor, then measurements of cervical collagen may provide an objective means of establishing the diagnosis or prognosis. We have established and reported a non-invasive means, called Collascope, to measure collagen cross-linking using light-induced fluorescence (LIF), and which is specifically designed to assess cervical ripening, and functions by measuring the natural fluorescence of non-soluble collagen in the cervix. Studies conducted in animals and humans in a variety of settings indicate that cervical function can be successfully monitored using the Collascope during pregnancy: LIF correlates negatively with gestational age and positively with time-to-delivery interval, and is predictive of delivery within 24h. Additionally LIF is significantly lower in women with cervical insufficiency. We suggest that the Collascope might be useful to better define management in cases of spontaneous preterm or induced term cervical ripening. From our studies and others, it is clear that in forecasting (pre-)term cervical ripening, the capability of the technologies and bioassays that have been generally accepted into clinical practice are limited. Any devices shown to be superior to the clinically accepted tests currently used should be quite useful for clinicians. The Collascope offers an objective measurement of both the function and state of the cervix, by directly measuring collagen cross-linking using LIF.
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Affiliation(s)
- Dietmar Schlembach
- Department of Obstetrics and Gynecology, Medical University of Graz, Graz, Austria.
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19
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Bauer M, Mazza E, Nava A, Zeck W, Eder M, Bajka M, Cacho F, Lang U, Holzapfel GA. In vivo characterization of the mechanics of human uterine cervices. Ann N Y Acad Sci 2007; 1101:186-202. [PMID: 17363446 DOI: 10.1196/annals.1389.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The uterine cervix has to provide mechanical resistance to ensure a normal development of the fetus. This is guaranteed by the composition of its extracellular matrix, which functions as a fiber-reinforced composite. At term a complex remodeling process allows the cervical canal to open for birth. This remodeling is achieved by changes in the quality and quantity of collagen fibers and ground substance and their interplay, which influences the biomechanical behavior of the cervix but also contributes to pathologic conditions such as cervical incompetence (CI). We start by reviewing the anatomy and histological composition of the human cervix, and discuss its physiologic function and pathologic condition in pregnancy including biomechanical aspects. Established diagnostic methods on the cervix (palpation, endovaginal ultrasound) used in clinics as well as methods for assessment of cervical consistency (light-induced fluorescence, electrical current, and impedance) are discussed. We show the first clinical application of an aspiration device, which allows in vivo testing of the biomechanical properties of the cervix with the aim to establish the physiological biomechanical changes throughout gestation and to detect pregnant women at risk for CI. In a pilot study on nonpregnant cervices before and after hysterectomy we found no considerable difference in the biomechanical response between in vivo and ex vivo. An outlook on further clinical applications during pregnancy is presented.
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Affiliation(s)
- Margit Bauer
- Department of Obstetrics and Gynecology, Medical University Graz, Graz, Austria
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20
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Hoe YSG, Gurewitsch ED, Shaahinfar A, Hu ES, Sampattavanich S, Ruffner M, Ching KHS, Allen RH. Measuring bioimpedance in the human uterine cervix: towards early detection of preterm labor. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2004:2368-72. [PMID: 17270746 DOI: 10.1109/iembs.2004.1403686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We have created a bioimpedance probe designed to detect subtle changes in human cervical tissue composition in vivo, and thereby detect the onset of cervical remodeling in a noninvasive manner sooner than existing clinical methods allow. Our cervical bioimpedance measurement device, which can be used during a routine pelvic examination, is composed of a contoured probe with disposable tip and, within the probe's handle, a bioimpedance sensor equipped with an integrated chip capable of generating sinusoidal voltage of varying frequencies. A constant force spring assures consistent measurements through a range of contact forces applied. An activation switch allows the operator to control the application of current. The sensor can be synchronized with a computer data storage and analysis system, which interfaces with the device. With the probe placed in contact with a collagen gels of varying concentration, the relationship between measured bioimpedance and collagen concentration is verified to be positive exponential (R/sup 2/=0.94) and repeatability in saline solution showed that measurements varied by less than +/-10% over 20 trials. Finally, a variety of user-applied forces showed that impedance values plateau when forces exceed 1N.
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Affiliation(s)
- Y S G Hoe
- Dept. of Biomed. Eng., Johns Hopkins Univ., Baltimore, MD, USA
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Comparison of human uterine cervical electrical impedance measurements derived using two tetrapolar probes of different sizes. Biomed Eng Online 2006; 5:62. [PMID: 17125510 PMCID: PMC1684260 DOI: 10.1186/1475-925x-5-62] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Accepted: 11/24/2006] [Indexed: 11/10/2022] Open
Abstract
Background We sought to compare uterine cervical electrical impedance spectroscopy measurements employing two probes of different sizes, and to employ a finite element model to predict and compare the fraction of electrical current derived from subepithelial stromal tissue. Methods Cervical impedance was measured in 12 subjects during early pregnancy using 2 different sizes of the probes on each subject. Results Mean cervical resistivity was significantly higher (5.4 vs. 2.8 Ωm; p < 0.001) with the smaller probe in the frequency rage of 4–819 kHz. There was no difference in the short-term intra-observer variability between the two probes. The cervical impedance measurements derived in vivo followed the pattern predicted by the finite element model. Conclusion Inter-electrode distance on the probes for measuring cervical impedance influences the tissue resistivity values obtained. Determining the appropriate probe size is necessary when conducting clinical studies of resistivity of the cervix and other human tissues.
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Brown BH, Gonzalez-Correa CA, Bremner J, Tidy JA. Impedance spectral measurements made through a membrane infection barrier. Med Biol Eng Comput 2006; 44:1085-91. [PMID: 17093953 DOI: 10.1007/s11517-006-0126-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Accepted: 10/10/2006] [Indexed: 10/23/2022]
Abstract
Impedance spectra of superficial tissues can be used to detect pre-malignant changes in the cervix but require electrical contact to be made between a probe and the tissue. Using a membrane which is permeable to ions but forms a barrier to agents of infection should enable impedance spectra to be measured without causing an infection risk to the patient. The properties required of such a membrane are considered and measurements on two suitable membranes are presented. It is shown that impedance spectra can be measured through a thin natural cellulose based membrane (Cuprophan) and that these are not significantly different from directly measured spectra. The ability of the membranes to block a virus is tested using expired polio virus vaccine.
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Affiliation(s)
- Brian H Brown
- Medical Physics and Clinical Engineering, University of Sheffield, Royal Hallamshire Hospital, Sheffield S102JF, UK.
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Wilkinson BA, Smallwood RH, Keshtar A, Lee JA, Hamdy FC. Electrical impedance spectroscopy and the diagnosis of bladder pathology: a pilot study. J Urol 2002; 168:1563-7. [PMID: 12352458 DOI: 10.1097/00005392-200210010-00085] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE Carcinoma in situ is an aggressive form of bladder cancer with a high propensity for invasion if left untreated. On cystoscopy these flat lesions cannot be differentiated from other erythematous, potentially benign areas and they require biopsy for definitive diagnosis. Other methods of detecting carcinoma in situ remain experimental. We assessed the effectiveness of electrical impedance spectroscopy, a method that measures the variation of electrical current flow with frequency through the mucosa, for differentiating various pathological changes in the urothelium. MATERIALS AND METHODS We obtained 250 impedance measurements immediately after resection in 35 cystectomy specimens using a custom designed probe. Three consecutive readings were recorded per point to assess reproducibility and punch biopsy was done at the measurement site. RESULTS Changes in the urothelium were classified histologically into 7 subgroups according to the degree of edema and inflammation. Electrical impedance spectroscopy measurements were able to separate benign and malignant changes when tested as a group (p <0.001), although some individual points overlapped. Edema also had a significant effect on tissue impedance (p <0.001). CONCLUSIONS Using measurements we established patterns of electrical impedance in the human bladder. Early results suggest that this minimally invasive technique is able to differentiate benign and malignant bladder pathologies. However, it requires further refinement and evaluation at lower frequencies, where the greatest impedance difference in benign and malignant tissues is expected.
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Affiliation(s)
- B A Wilkinson
- Academic Urology Unit and Department of Medical Physics and Engineering, University of Sheffield, Royal Hallamshire Hospital, United Kingdom
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Wilkinson BA, Smallwood RH, Keshtar A, Lee JA, Hamdy FC. Electrical impedance spectroscopy and the diagnosis of bladder pathology: a pilot study. J Urol 2002; 168:1563-7. [PMID: 12352458 DOI: 10.1016/s0022-5347(05)64521-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE Carcinoma in situ is an aggressive form of bladder cancer with a high propensity for invasion if left untreated. On cystoscopy these flat lesions cannot be differentiated from other erythematous, potentially benign areas and they require biopsy for definitive diagnosis. Other methods of detecting carcinoma in situ remain experimental. We assessed the effectiveness of electrical impedance spectroscopy, a method that measures the variation of electrical current flow with frequency through the mucosa, for differentiating various pathological changes in the urothelium. MATERIALS AND METHODS We obtained 250 impedance measurements immediately after resection in 35 cystectomy specimens using a custom designed probe. Three consecutive readings were recorded per point to assess reproducibility and punch biopsy was done at the measurement site. RESULTS Changes in the urothelium were classified histologically into 7 subgroups according to the degree of edema and inflammation. Electrical impedance spectroscopy measurements were able to separate benign and malignant changes when tested as a group (p <0.001), although some individual points overlapped. Edema also had a significant effect on tissue impedance (p <0.001). CONCLUSIONS Using measurements we established patterns of electrical impedance in the human bladder. Early results suggest that this minimally invasive technique is able to differentiate benign and malignant bladder pathologies. However, it requires further refinement and evaluation at lower frequencies, where the greatest impedance difference in benign and malignant tissues is expected.
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Affiliation(s)
- B A Wilkinson
- Academic Urology Unit and Department of Medical Physics and Engineering, University of Sheffield, Royal Hallamshire Hospital, United Kingdom
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