Novel optical detection system for in vivo identification and localization of cervical intraepithelial neoplasia

Concentration of FAD as a marker for cervical precancer detection

We report the ex vivo results of an in-house fabricated portable device based on polarized fluorescence measurements in the clinical environment. This device measures the polarized fluorescence and elastic scattering spectra with 405-nm laser and white light sources, respectively. The dominating fluorophore with 405-nm excitation is flavin adenine dinucleotide (FAD) with a fluorescence peak around 510 nm. The measured spectra are highly modulated by the interplay of scattering and absorption effects. Due to this, valuable information gets masked. To reduce these effects, intrinsic fluorescence was extracted by normalizing polarized fluorescence spectra with polarized elastic scattering spectra obtained. A number of fluorophores contribute to the fluorescence spectra and need to be decoupled to understand their roles in the progression of cancer. Nelder-Mead method has been utilized to fit the spectral profile with Gaussian to decouple the different bands of contributing fluorophores (FAD and porphyrin). The change in concentration of FAD during disease progression manifests in the change in ratio of total area to FWHM of its Gaussian profile. Receiver operating characteristic (ROC) curve analysis has been used to discriminate different grades of cervical precancer by using the ratio as input parameter. The sensitivity and specificity for discrimination of normal samples from CIN I (cervical intraepithelial neoplasia) are 75% and 54%, respectively. Further, the normal samples can be discriminated from CIN II samples with 100% and 82% sensitivity and specificity, respectively, and the CIN I from CIN II samples can also be discriminated with 100% sensitivity and 90% specificity, respectively. The results show that the change in the concentration of (FAD) can be used as a marker to discriminate the different grades of the cancer and biochemical changes at an early stage of the cancer can also be monitored with this technique.

Intrinsic fluorescence for cervical precancer detection using polarized light based in-house fabricated portable device

An in-house fabricated portable device has been tested to detect cervical precancer through the intrinsic fluorescence from human cervix of the whole uterus in a clinical setting. A previously validated technique based on simultaneously acquired polarized fluorescence and polarized elastic scattering spectra from a turbid medium is used to extract the intrinsic fluorescence. Using a diode laser at 405 nm, intrinsic fluorescence of flavin adenine dinucleotide, which is the dominant fluorophore and other contributing fluorophores in the epithelium of cervical tissue, has been extracted. Different grades of cervical precancer (cervical intraepithelial neoplasia; CIN) have been discriminated using principal component analysis-based Mahalanobis distance and linear discriminant analysis. Normal, CIN I and CIN II samples have been discriminated from one another with high sensitivity and specificity at 95% confidence level. This ex vivo study with cervix of whole uterus samples immediately after hysterectomy in a clinical environment indicates that the in-house fabricated portable device has the potential to be used as a screening tool for in vivo precancer detection using intrinsic fluorescence.

Development of a Multimodal Colposcopy for Characterization of Cervical Intraepithelial Neoplasia

To develop and evaluate the clinical application of a multimodal colposcopy combining multispectral reflectance, autofluorescence, and red, green, blue (RGB) imaging for noninvasive characterization of cervical intraepithelial neoplasia (CIN). We developed a multimodal colposcopy system that combined multispectral reflectance, autofluorescence, and RGB imaging for noninvasive characterization of CIN. We studied the optical properties of cervical tissue first; then the imaging system was designed and tested in a clinical trial where comprehensive datasets were acquired and analyzed to differentiate between squamous normal and high grade types of cervical tissue. The custom-designed multimodal colposcopy is capable of acquiring multispectral reflectance images, autofluorescence images, and RGB images of cervical tissue consecutively. The classification algorithm was employed on both normal and abnormal cases for image segmentation. The performance characteristics of this system were comparable to the gold standard histopathologic measurements with statistical significance. Our pilot study demonstrated the clinical potential of this multimodal colposcopic system for noninvasive characterization of CIN. The proposed system was simple, noninvasive, cost-effective, and portable, making it a suitable device for deployment in developing countries or rural regions of limited resources.

The Use of a Novel Optical Algorithm in the Diagnosis of Cervical Pre-Invasive Pathology - A Preliminary Proof of Principal Study

OBJECTIVE

To develop a novel optical probe monitoring cervical tissues in real-time and to compare the new imaging technique to actual cervical pathologic findings on resected cone biopsy specimens.

METHODS

A loop electro-excisional procedure was performed on 15 women with a biopsy diagnosis of dysplasia. The conization specimen was then assessed with the novel optical system and results recorded. The 'normal' and 'abnormal' areas were tested by the optical setup at several points. Extracted parameters were used as the input of the classifier function of a logistic regression algorithm model to assess for system accuracy vs. clinical examination.

RESULTS

Ninety-seven samples were taken - forty-five samples from 'abnormal zones' and 42 samples from 'normal zones', as defined by the surgeon. The pathologist diagnosed 58 samples as dysplastic and 39 samples as normal. The novel optical method predicted 58 sample points as abnormal and 39 points as normal. The sensitivity of the system was 90% with a specificity of 77%. The probability of correct differentiation of dysplastic cervical tissue from normal cervical tissue was 85%.

CONCLUSIONS

The optical probe and the algorithms of image processing in combination with the logistic regression algorithm correlated well with pathology results for cervical dysplasia ex-vivo.

Early detection of high-grade squamous intraepithelial lesions in the cervix with quantitative spectroscopic imaging

Quantitative spectroscopy has recently been extended from a contact-probe to wide-area spectroscopic imaging to enable mapping of optical properties across a wide area of tissue. We train quantitative spectroscopic imaging (QSI) to identify cervical high-grade squamous intraepithelial lesions (HSILs) in 34 subjects undergoing the loop electrosurgical excision procedure (LEEP subjects). QSI's performance is then prospectively evaluated on the clinically suspicious biopsy sites from 47 subjects undergoing colposcopic-directed biopsy. The results show the per-subject normalized reduced scattering coefficient at 700 nm (An) and the total hemoglobin concentration are significantly different (p<0.05) between HSIL and non-HSIL sites in LEEP subjects. An alone retrospectively distinguishes HSIL from non-HSIL with 89% sensitivity and 83% specificity. It alone applied prospectively on the biopsy sites distinguishes HSIL from non-HSIL with 81% sensitivity and 78% specificity. The findings of this study agree with those of an earlier contact-probe study, validating the robustness of QSI, and specifically An, for identifying HSIL. The performance of An suggests an easy to use and an inexpensive to manufacture monochromatic instrument is capable of early cervical cancer detection, which could be used as a screening and diagnostic tool for detecting cervical cancer in low resource countries.

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.

Parallel factor analysis of ovarian autofluorescence as a cancer diagnostic

BACKGROUND AND OBJECTIVES

Endogenous fluorescence from certain amino acids, structural proteins, and enzymatic co-factors in tissue is altered by carcinogenesis. We evaluate the potential of these changes in fluorescence to predict a diagnosis of malignancy and to estimate the risk of developing ovarian cancer.

STUDY DESIGN/MATERIALS AND METHODS

Ovarian biopsies were interrogated over 270-550 nm excitation and fluorescence was collected from 290 to 700 nm. Two hundred forty-nine measurements were performed on 49 IRB-consented patients undergoing oophorectomy. Data are analyzed using parallel factor analysis to determine excitation and emission spectra of the underlying fluorophores that contribute to the total detected fluorescence intensity.

RESULTS

Using multivariate normal distribution fits and cross-validation techniques, sensitivity and specificity of 88% and 93%, respectively, are achieved when classifying malignant samples versus others, while 88% and 80%, respectively, are achieved when classifying normal post-menopausal patients as being either at high- or low-risk of developing ovarian cancer based on their personal and family history of cancer. Performance of classifying cancer increases when the normal group does not include benign neoplasm and endometriosis samples. Performance of high- versus low-risk classification decreases when normal samples include both pre- and post-menopausal women. Excitation over 270-400 and 380-560 nm, respectively, have the best diagnostic performance for cancer detection and risk-status assessment.

CONCLUSIONS

Assessing the endogenous fluorescence could be useful in screening women at increased risk of developing ovarian cancer.

Evaluation of high-performance liquid chromatography laser-induced fluorescence for serum protein profiling for early diagnosis of oral cancer

The present work deals with the evaluation of a high-performance liquid chromatography laser-induced fluorescence (HPLC-LIF) technique developed in our laboratory for early detection of oral cancer from protein profiles of body fluids. The results show that protein profiles of serum samples from a given class of samples, say, normal, premalignant, or malignant, are statistically very close to each other, while profiles of members of any class are significantly different from other classes. The performance of the technique is evaluated by the use of sensitivity and specificity pairs, receiver operating characteristic (ROC) analysis, and Youden's Index. The technique uses protein profile differences in serum samples, registered by the HPLC-LIF technique. The study is carried out using serum samples from volunteers diagnosed as normal or premalignant clinically, and as malignant by histopathology. The specificities and sensitivities of the HPLC-LIF method at an ideal threshold (M-distance = 2) for normal, malignant, and premalignant classes are 100, 69.5, and 61.5%, and 86.5, 87.5, and 87.5% respectively.

Quantitative physiology of the precancerous cervix in vivo through optical spectroscopy

Cervical cancer is the second most common female cancer worldwide. The ability to quantify physiological and morphological changes in the cervix is not only useful in the diagnosis of cervical precancers but also important in aiding the design of cost-effective detection systems for use in developing countries that lack well-established screening and diagnostic programs. We assessed the capability of a diffuse reflectance spectroscopy technique to identify contrasts in optical biomarkers that vary with different grades of cervical intraepithelial neoplasia (CIN) from normal cervical tissues. The technology consists of an optical probe and an instrument (with broadband light source, dispersive element, and detector), and a Monte Carlo algorithm to extract optical biomarker contributions including total hemoglobin (Hb) concentration, Hb saturation, and reduced scattering coefficient from the measured spectra. Among 38 patients and 89 sites examined, 46 squamous normal sites, 18 CIN 1, and 15 CIN 2(+) sites were included in the analysis. Total Hb was statistically higher in CIN 2(+) (18.3 +/- 3.6 microM, mean +/- SE) compared with normal (9.58 +/- 1.91 microM) and CIN 1 (12.8 +/- 2.6 microM), whereas scattering was significantly reduced in CIN 1 (8.3 +/- 0.8 cm(-1)) and CIN 2(+) (8.6 +/- 1.0 cm(-1)) compared with normal (10.2 +/- 1.1 cm(-1)). Hemoglobin saturation was not significantly altered in CIN 2(+) compared with normal and CIN 1. The difference in total Hb is likely because of stromal angiogenesis, whereas decreased scattering can be attributed to breakdown of collagen network in the cervical stroma.

Quantitative spectroscopic imaging for non-invasive early cancer detection

We report a fully quantitative spectroscopy imaging instrument for wide area detection of early cancer (dysplasia). This instrument provides quantitative maps of tissue biochemistry and morphology, making it a potentially powerful surveillance tool for objective early cancer detection. We describe the design, construction, calibration, and first clinical application of this new system. We demonstrate its accuracy using physical tissue models. We validate its diagnostic ability on a resected colon adenoma, and demonstrate feasibility of in vivo imaging in the oral cavity.

Increased detection of high-grade cervical intraepithelial neoplasia utilizing an optical detection system as an adjunct to colposcopy

OBJECTIVE

To evaluate the impact of using a novel optical detection system (ODS) as an adjunct to colposcopy.

METHODS

A multicenter internally controlled trial designed to evaluate the performance of an ODS system (LUMA MediSpectra, Lexington, MA) used as an adjunct to colposcopy among women referred for the evaluation of an abnormal cervical cytology result was conducted at 7 colposcopy clinics in the United States and enrolled 227 women. After exclusions, 193 women remained in the analysis. The main study outcomes were incremental increases in true positives (CIN 2,3 and cancer, or CIN 2+) and false positives (women with additional cervical biopsies not found to be CIN 2+).

RESULTS

Initial colposcopy identified 41 cases of CIN 2+ for a true positive (TP) rate of 21.2%. Adjunctive use of ODS identified an additional 9 cases of CIN 2+ which corresponds to an incremental ODS TP rate of 4.7% (95% CI 2.2% to 8.7%). Adjunctive use of ODS therefore resulted in a 22.0% (95% CI 6.1% to 37.8%) relative gain in the number of women with CIN 2+ compared to colposcopy alone. The false positive (FP) rate for initial colposcopy was 51.8% (100 of 193 women). An additional 35 subjects had an ODS-directed biopsy that was not diagnosed as CIN 2+, yielding an incremental FP rate of 18.1% (95% CI 13.0% to 24.3%).

CONCLUSIONS

Adjunctive use of ODS with colposcopy provides a significant increase in the detection of CIN 2+ in women referred for the evaluation of abnormal cytology results.

Effective cervical neoplasia detection with a novel optical detection system: A randomized trial

OBJECTIVE

To assess whether the use of a novel optical detection system (ODS) as an adjunct to colposcopy increases the detection of biopsy-confirmed CIN 2,3.

METHODS

This is a multicenter two-arm randomized trial comparing colposcopy alone with colposcopy plus a pre-commercial ODS system that utilizes fluorescence, white light tissue reflectance, and cervical video imaging. Patients were recruited from 13 colposcopy clinics in a variety of practice settings. 2299 women referred for the evaluation of an abnormal cervical cytology were randomized with stratification by cytology; subsequently 113 women were excluded for a variety of reasons. The main study outcomes were differences in true-positive rates (CIN 2,3 and cancer identified) and false-positive rates between the study arms.

RESULTS

The true-positive (TP) rates were 14.4% vs. 11.4% (p=0.035, one-sided) for the combined colposcopy and ODS arm compared to colposcopy-only arm, respectively, in women with either an atypical squamous cell (ASC) or low-grade squamous intraepithelial lesion (LSIL) cytology result. TP rates were similar between the two arms among women referred for the evaluation of HSIL. The 26.5% gain in true-positives observed with the use of ODS and colposcopy among women referred for an ASC or LSIL cytology was achieved with only a fractional increase in number of biopsies obtained per patient (0.30) and a modest increase in false-positive rate (4%). In the combined colposcopy and ODS arm among women with ASC or LSIL, the PPV of biopsies indicated by ODS was 15.0% and the PPV of biopsies indicated by colposcopy was 15.2%. Joint hypothesis testing indicates that ODS and colposcopy provides benefit compared to colposcopy alone among women with ASC or LSIL.

CONCLUSIONS

Combining ODS with colposcopy provides a clinically meaningful increase in the detection of CIN 2,3 in women referred for the evaluation of mildly abnormal cytology results.