Optical coherence tomography as a non-invasive imaging technique for preinvasive and invasive neoplasia of the uterine cervix

Characteristics and utility of high-resolution optical coherence microscopy images of endocervical canal lesions

OBJECTIVES

To investigate optical coherence microscopy (OCM) imaging features and the application value of these high-resolution images for identifying endocervical canal lesions (ECLs), which is a clinical dilemma in cervical cancer screening programs.

METHODS

In total, 520 OCM images were obtained by scanning the cervical canal lesions with an ultra-high-resolution OCM system (204 specimens from 73 patients). The OCM morphologic characteristics of ECLs were observed and summarized, and then 3 researchers performed a diagnostic test of OCM images of cervical canal lesions. The accuracy, sensitivity, specificity, positive predictive value, negative predictive value, 95% confidence interval of each parameter, and interinvestigator agreement (κ) were calculated.

RESULTS

Normal endocervix, cysts, squamous metaplasia, high-grade squamous intraepithelial lesions involving glands, and invasive carcinoma had distinct OCM characteristics, which correlated well with corresponding H&E histologic sections. The accuracy, sensitivity, and specificity of the 3 researchers were 90.6%, 89.3% (95% CI, 86.5%-91.7%) and 91.6% (95% CI, 89.2%-93.5%), respectively. The positive predictive value was 90.1% (95% CI, 87.3%-92.4%), and the negative predictive value was 90.9% (95% CI, 88.5%-92.9%), with almost perfect agreement (κ = 0.874).

CONCLUSIONS

The application of the OCM system in cervical canal lesions is feasible and could help improve detection of occult ECLs in cervical cancer screening programs. This study lays the foundation for further research on OCM in cervical canal lesions in vivo, which also has a potential impact on projecting pathologic evaluation beyond what is currently possible, perhaps globally.

Optical Coherence Tomography Can Reduce Colposcopic Referral Rates in Patients With High-Risk Human Papillomavirus

OBJECTIVE

This study aimed to evaluate the feasibility of combined human papillomavirus (HPV) and optical coherence tomography (OCT) cervical cancer screening strategies.

MATERIALS AND METHODS

The OCT and cytology results were compared with the pathological results to calculate the sensitivity, specificity, positive predictive value, negative predictive value, and immediate cervical intraepithelial neoplasia grade 3 or worse (CIN3+) risk. The authors compared the efficiency of colposcopy by using different triage strategies. They discussed differentiation in OCT screening in different age groups.

RESULTS

Eight hundred thirteen participants with high-risk HPV-positive and cervical cytology results underwent OCT before colposcopy between March 1 and October 1, 2021. The HPV16/18 genotyping with OCT triage has a specificity of CIN3+ lesions (61.1%; 95% CI = 57.6%-64.6%), intraepithelial neoplasia grade 2 or worse (CIN2+) (66.0%; 95% CI = 62.4%-69.6%). The HPV16/18 genotyping with cytology triage has a specificity of CIN3+ (44.0%; 95% CI = 40.4%-47.6%), CIN2+ (47.0%; 95% CI = 43.2%-50.8%). The OCT triage has a higher positive predictive value compared with the cytology, with a significant difference in CIN2+ lesions (45.0%; 95% CI = 38.8%-51.3% vs 29.2%; 95% CI = 24.7%-33.7%).

CONCLUSIONS

The combination of OCT and high-risk HPV triage (both genotyping and nongenotyping) had a similar immediate CIN3+ risk stratification and reduced the number of colposcopies compared with the cytological triage strategy.

Efficacy of optical coherence tomography in the triage of women with minor abnormal cervical cytology before colposcopy

OBJECTIVES

To evaluate the efficacy of Optical Coherence Tomography (OCT) for detecting cervical lesions in women with minor abnormal cytology results (atypical squamous cells of undetermined significance (ASC-US) and low-grade squamous intraepithelial lesion (LSIL)).

METHODS

A prospective study was conducted at gynecologic clinic from Mar 2021 to Sep 2021. The recruited women with cervical cytological findings of ASC-US or LSIL were inspected with OCT before colposcopy-directed cervical biopsy. The diagnostic performance of OCT, alone and in combination with high-risk human papillomavirus (hrHPV) testing were evaluated to detect cervical intraepithelial neoplasia of grade 2 or worse (CIN2+)/CIN3 or worse (CIN3+). The rate of colposcopy referral and the immediate risk of CIN3+ of OCT were calculated.

RESULTS

A total of 349 women with minor abnormal cervical cytology results were enrolled. For detection of CIN2+/CIN3+, the sensitivity and NPV of OCT were lower than those of hrHPV testing (CIN2+: 71.3% vs. 95.4%, 89.0% vs. 91.1%, P < 0.001; CIN3+: 75% vs. 93.8%, 96.5% vs. 95.6%, P < 0.001), but the specificity, accuracy and PPV were higher than those of hrHPV testing (CIN2+: 77.5% vs. 15.6%, 75.9% vs. 35.5%, 51.2% vs. 27.3%, P < 0.001; CIN3+: 69.4% vs. 13.6%, 69.9% vs. 20.9%, 19.8% vs. 9.9%, P < 0.001). OCT combined with hrHPV testing (CIN2+: 80.9%; CIN3+: 72.6%) showed higher specificity than that of OCT alone (P < 0.001). The colposcopy referral rate base on OCT classification was lower than that based on hrHPV testing (34.7% vs. 87.1%, P < 0.001). Patients with hrHPV-positive ASC-US and hrHPV-negative LSIL cytology, the immediate CIN3+ risk in OCT negative cases was less than 4%.

CONCLUSIONS

OCT alone or combination with hrHPV testing shows good performance for detecting CIN2+/CIN3+ in patients with ASC-US/LSIL cytology. OCT is an effective method for colposcopy triage in women with hrHPV-positive ASC-US and hrHPV-negative LSIL cytology.

Heterogeneous microstructural changes of the cervix influence cervical funneling

The cervix acts as a dynamic barrier between the uterus and vagina, retaining the fetus during pregnancy and allowing birth at term. Critical to this function, the physical properties of the cervix change, or remodel, but abnormal remodeling can lead to preterm birth (PTB). Although cervical remodeling has been studied, the complex 3D cervical microstructure has not been well-characterized. In this complex, dynamic, and heterogeneous tissue microenvironment, the microstructural changes are likely also heterogeneous. Using quantitative, 3D, second-harmonic generation microscopy, we demonstrate that rat cervical remodeling during pregnancy is not uniform across the cervix; the collagen fibers orient progressively more perpendicular to the cervical canals in the inner cervical zone, but do not reorient in other regions. Furthermore, regions that are microstructurally distinct early in pregnancy become more similar as pregnancy progresses. We use a finite element simulation to show that heterogeneous regional changes influence cervical funneling, an important marker of increased risk for PTB; the internal cervical os shows ∼6.5x larger radial displacement when fibers in the inner cervical zone are parallel to the cervical canals compared to when fibers are perpendicular to the canals. Our results provide new insights into the microstructural and tissue-level cervical changes that have been correlated with PTB and motivate further clinical studies exploring the origins of cervical funneling. STATEMENT OF SIGNIFICANCE: Cervical funneling, or dilation of the internal cervical os, is highly associated with increased risk of preterm birth. This study explores the 3D microstructural changes of the rat cervix during pregnancy and illustrates how these changes influence cervical funneling, assuming similar evolution in rats and humans. Quantitative imaging showed that microstructural remodeling during pregnancy is nonuniform across cervical regions and that initially distinct regions become more similar. We report, for the first time, that remodeling of the inner cervical zone can influence the dilation of the internal cervical os and allow the cervix to stay closed despite increased intrauterine pressure. Our results suggest a possible relationship between the microstructural changes of this zone and cervical funneling, motivating further clinical investigations.

Discrimination of fresh frozen non-tumour and tumour brain tissue using spectrochemical analyses and a classification model

Introduction: In order for brain tumours to be successfully treated, maximal resection is beneficial. A method to detect infiltrative tumour edges intraoperatively, improving on current methods would be clinically useful. Vibrational spectroscopy offers the potential to provide a handheld, reagent-free method for tumour detection.Purpose: This study was designed to determine the ability of both Raman and Fourier-transform infrared (FTIR) spectroscopy towards differentiating between normal brain tissue, glioma or meningioma.Method: Unfixed brain tissue, which had previously only been frozen, comprising normal, glioma or meningioma tissue was placed onto calcium fluoride slides for analysis using Raman and attenuated total reflection (ATR)-FTIR spectroscopy. Matched haematoxylin and eosin slides were used to confirm tumour areas. Analyses were then conducted to generate a classification model.Results: This study demonstrates the ability of both Raman and ATR-FTIR spectroscopy to discriminate tumour from non-tumour fresh frozen brain tissue with 94% and 97.2% of cases correctly classified, with sensitivities of 98.8% and 100%, respectively. This decreases when spectroscopy is used to determine tumour type.Conclusion: The study demonstrates the ability of both Raman and ATR-FTIR spectroscopy to detect tumour tissue from non-tumour brain tissue with a high degree of accuracy. This demonstrates the ability of spectroscopy when targeted for a cancer diagnosis. However, further improvement would be required for a classification model to determine tumour type using this technology, in order to make this tool clinically viable.

Computer-Aided Diagnosis of Label-Free 3-D Optical Coherence Microscopy Images of Human Cervical Tissue

OBJECTIVE

Ultrahigh-resolution optical coherence microscopy (OCM) has recently demonstrated its potential for accurate diagnosis of human cervical diseases. One major challenge for clinical adoption, however, is the steep learning curve clinicians need to overcome to interpret OCM images. Developing an intelligent technique for computer-aided diagnosis (CADx) to accurately interpret OCM images will facilitate clinical adoption of the technology and improve patient care.

METHODS

497 high-resolution three-dimensional (3-D) OCM volumes (600 cross-sectional images each) were collected from 159 ex vivo specimens of 92 female patients. OCM image features were extracted using a convolutional neural network (CNN) model, concatenated with patient information [e.g., age and human papillomavirus (HPV) results], and classified using a support vector machine classifier. Ten-fold cross-validations were utilized to test the performance of the CADx method in a five-class classification task and a binary classification task.

RESULTS

An 88.3 ± 4.9% classification accuracy was achieved for five fine-grained classes of cervical tissue, namely normal, ectropion, low-grade and high-grade squamous intraepithelial lesions (LSIL and HSIL), and cancer. In the binary classification task [low-risk (normal, ectropion, and LSIL) versus high-risk (HSIL and cancer)], the CADx method achieved an area-under-the-curve value of 0.959 with an 86.7 ± 11.4% sensitivity and 93.5 ± 3.8% specificity.

CONCLUSION

The proposed deep-learning-based CADx method outperformed four human experts. It was also able to identify morphological characteristics in OCM images that were consistent with histopathological interpretations.

SIGNIFICANCE

Label-free OCM imaging, combined with deep-learning-based CADx methods, holds a great promise to be used in clinical settings for the effective screening and diagnosis of cervical diseases.

Label-free imaging and spectroscopy for early detection of cervical cancer

The label-free imaging and spectroscopy method was studied on cervical unstained tissue sections obtained from 36 patients. The native fluorescence spectra of tissues are analyzed by the optical redox ratio (ORR), which is defined as fluorescence intensity ratio between NADH and FAD, and indicates the metabolism change with the cancer development. The ORRs of normal tissues are consistently higher than those of precancer or cancerous tissues. A criterion line of ORR at 5.0 can be used to discriminate cervical precancer/cancer from normal tissues. The sensitivity and specificity of the native fluorescence spectroscopy method for cervical cancer diagnosis are determined as 100% and 91%. Moreover, the native fluorescence spectroscopy study is much more sensitive on the healthy region of cervical precancer/cancer patients compared with the traditional clinical staining method. The results suggest label-free imaging and spectroscopy is a fast, highly sensitive and specific method on the detection of cervical cancer.

Ultrahigh-resolution optical coherence microscopy accurately classifies precancerous and cancerous human cervix free of labeling

Cervical cancer remains the fourth most common cause of cancer worldwide and the third leading cause of cancer deaths for women in developing countries. Traditional screening tools, such as human papillomavirus and Pap tests, cannot provide results in real-time and cannot localize suspicious regions. Colposcopy-directed biopsies are invasive in nature and only a few sites of the cervix may be chosen for investigation. A non-invasive, label-free and real-time imaging method with a resolution approaching that of histopathology is desirable for early detection of the disease.

Methods: Ultrahigh-resolution optical coherence microscopy (OCM) is an emerging imaging technique used to obtain 3-dimensional (3-D) “optical biopsies” of biological samples with cellular resolution. In this study, 497 3-D OCM datasets from 159 specimens were collected from 92 patients.

Results: Distinctive patterns for normal cervix, squamocolumnar junction, ectropion, low-grade and high-grade squamous intraepithelial lesions (LSIL and HSIL) and invasive cervical lesions were clearly observed from OCM images, which matched well with corresponding histological slides. OCM images demonstrated a sensitivity of 80% (95% confidence interval, CI, 72%-86%) and a specificity of 89% (95% CI, 84%-93%) for detecting high-risk lesions (HSIL and invasive lesions) when blindly tested by three investigators. A substantial inter-observer agreement was observed (κ=0.627), which showed high diagnostic consistency among three investigators.

Conclusion: These results laid the foundation for future non-invasive optical evaluation of cervical tissue in vivo, which could lead to a less invasive and more effective screening and “see-and-treat” strategy for the management of cervical cancer.

Diagnostic accuracy of optical coherence tomography in bladder cancer patients: A systematic review and meta-analysis

A meta-analysis was performed to evaluate the accuracy of optical coherence tomography (OCT) for diagnostic accuracy studies in bladder cancer patients. English language studies reporting the diagnostic accuracy of OCT for bladder cancer were retrieved from the PubMed, EMBASE and Cochrane Library databases in December 2014. Histopathology was a reference standard. Sensitivities, specificities, positive likelihood ratios and negative likelihood ratios were calculated, and summary receiver operating characteristic curves were drawn to determine the diagnostic accuracy of OCT. Finally, 9 eligible studies (468 patients) were included in our meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of OCT were 0.96 [95% confidence interval (CI): 0.94-0.98], 0.82 (95% CI: 0.80-0.85), 6.83 (95% CI: 3.24-14.1) and 0.05 (95% CI: 0.02-0.16), respectively. The summary diagnostic odds ratio was 138.88 (95% CI: 29.63-650.89) and the overall area under the curve was 0.9735. These results suggest that OCT has excellent diagnostic performance in patients with bladder cancer and recurrent lesions.

Review of optical coherence tomography in oncology

The application of optical coherence tomography (OCT) in the field of oncology has been prospering over the past decade. OCT imaging has been used to image a broad spectrum of malignancies, including those arising in the breast, brain, bladder, the gastrointestinal, respiratory, and reproductive tracts, the skin, and oral cavity, among others. OCT imaging has initially been applied for guiding biopsies, for intraoperatively evaluating tumor margins and lymph nodes, and for the early detection of small lesions that would often not be visible on gross examination, tasks that align well with the clinical emphasis on early detection and intervention. Recently, OCT imaging has been explored for imaging tumor cells and their dynamics, and for the monitoring of tumor responses to treatments. This paper reviews the evolution of OCT technologies for the clinical application of OCT in surgical and noninvasive interventional oncology procedures and concludes with a discussion of the future directions for OCT technologies, with particular emphasis on their applications in oncology.

Optical coherence tomography in gynecology: a narrative review

Modern gynecologic practice requires noninvasive diagnostics techniques capable of detecting morphological and functional alterations in tissues of female reproductive organs. Optical coherence tomography (OCT) is a promising tool for providing imaging of biotissues with high resolution at depths up to 2 mm. Design of the customized probes provides wide opportunities for OCT use in gynecology. This paper contains a retrospective insight into the history of OCT employment in gynecology, an overview of the existing gynecologic OCT probes, including those for combination with other diagnostic modalities, and state-of-the-art application of OCT for diagnostics of tumor and nontumor pathologies of female genitalia. Perspectives of OCT both in diagnostics and treatment planning and monitoring in gynecology are overviewed.

Optical techniques for cervical neoplasia detection

This paper provides an overview of the current research in the field of optical techniques for cervical neoplasia detection and covers a wide range of the existing and emerging technologies. Using colposcopy, a visual inspection of the uterine cervix with a colposcope (a binocular microscope with 3- to 15-fold magnification), has proven to be an efficient approach for the detection of invasive cancer. Nevertheless, the development of a reliable and cost-effective technique for the identification of precancerous lesions, confined to the epithelium (cervical intraepithelial neoplasia) still remains a challenging problem. It is known that even at early stages the neoplastic transformations of cervical tissue induce complex changes and modify both structural and biochemical properties of tissues. The different methods, including spectroscopic (diffuse reflectance spectroscopy, induced fluorescence and autofluorescence spectroscopy, Raman spectroscopy) and imaging techniques (confocal microscopy, optical coherence tomography, Mueller matrix imaging polarimetry, photoacoustic imaging), probe different tissue properties that may serve as optical biomarkers for diagnosis. Both the advantages and drawbacks of these techniques for the diagnosis of cervical precancerous lesions are discussed and compared.

Detection of cervical intraepithelial neoplasia by using optical coherence tomography in combination with microscopy

Optical coherence tomography (OCT) is a noninvasive high-resolution imaging technique that permits the detection of cancerous and precancerous lesions of the uterine cervix. The purpose of this study was to evaluate a new system that integrates an OCT device into a microscope. OCT images were taken from loop electrosurgical excision procedure (LEEP) specimens under microscopic guidance. The images were blinded with respect to their origin within the microscopic image and analyzed independently by two investigators using initially defined criteria and later compared to the corresponding histology. Sensitivity and specificity were calculated with respect to the correct identification of high-grade squamous intraepithelial lesions (HSIL). The interinvestigator agreement was assessed by using Cohen’s kappa statistics. About 160 OCT images were obtained from 20 LEEP specimens. Sixty randomly chosen images were used to define reproducible criteria for evaluation. The assessment of the remaining 100 images showed a sensitivity of 88% (second investigator 84%) and a specificity of 69% (65%) in detecting HSIL. Surgical microscopy-guided OCT appears to be a promising technique for immediate assessment of microanatomical changes. In the gynecological setting, the combination of OCT with a colposcope may improve the detection of high-grade squamous intraepithelial lesions.

Global spectral and local molecular connects for optical coherence tomography features to classify oral lesions towards unravelling quantitative imaging biomarkers

The biopsy based diagnosis of oral precancers like leukoplakia (OLK) and submucous fibrosis (OSF) as well as squamous cell carcinoma (OSCC) suffers from observer specific variability.

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.

Detection of cervical cancer based on photoacoustic imaging-the in-vitro results

In current clinical practice, the diagnosis of cervical cancer (CC) is mainly through the cervical screening followed by a necessary biopsy, but this method is labor consuming and expensive, and can only detect superficial lesions around the external cervical orifice. In contrast, photoacoustic imaging (PAI) is sensitive to the abnormal angiogenesis deep in the biological tissue, and may be capable for the intact scanning both around the external orifice and in cervical canal. In this paper, we for the first time put forward the photoacoustic diagnosis of CC. A total of 30 in-vitro experiments were carried out in this study, and the obtained depth maximum amplitude projection (DMAP) images were analyzed to evaluate the extent of the angiogenesis for different clinical stages of CC. Stronger absorption from the cervical lesions is observed relative to that of normal tissue. Paired t-test indicates that the difference in mean optical absorption (MOA) between normal tissue and cervical lesion has statistical significance with a confidential coefficient of 0.05. Statistical results also show that the MOAs of the cervical lesions are closely related to the severity of CC. These results imply that PAI may have great utility in the clinical diagnosis of CC.

Effect of optical clearing agents on optical coherence tomography images of cervical epithelium

Optical coherence tomography (OCT) can be used as an adjunct to colposcopy in order to detect precancerous and cancerous cervical lesions. Optical clearing agents (OCAs) temporarily reduce the optical scattering of biological tissues. The purpose of this study was to investigate their influence on OCT imaging. OCT images were taken from unsuspicious and suspicious areas of fresh conization specimens immediately after resection and 5, 10, and 20 min after application of dimethyl sulfoxide (DMSO) or polyethylene glycol (PEG). Corresponding histologies were obtained from all sites. The images taken 5, 10, and 20 min after application of OCA were compared to the initial images with respect to changes in brightness, contrast, and scanning depth using a standard nonparametric test of differences of proportions. Further, mean intensity backscattering curves were calculated from all OCT images in the histological groups CIN2, CIN3, inflammation, and normal epithelium. Mean difference profiles within each of these groups were determined, reflecting the mean differences between the condition before the application of OCA and the exposure times 5, 10, and 20 min, respectively. The null hypothesis was tested employing the Dicky-Fuller-test, Hotelings-test and run test. The visual analysis of 434 OCT images from 109 different sites of 24 conization specimens showed a statistically significant increase in brightness and contrast for normal and dysplastic epithelium after application of DMSO or PEG. Further, the analysis of mean intensity profiles suggests the existence of an increased backscattering intensity after application of DMSO or PEG. DMSO and PEG contribute substantially to optical clearing in cervical squamous epithelium and therefore influence OCT imaging in a positive way. With further refinement of the OCT technology, the observed changes may be beneficial in interpreting the tissue microstructure and identifying cervical intraepithelial neoplasia.

Acceptability of optical coherence tomography and abstinence requirements among women participating in microbicide safety trials

BACKGROUND

Developing effective and safe microbicides requires study procedures (e.g., technology used, abstinence requirements, and product use) that are acceptable to participants.

METHODS

Thirty women completed 4 study visits including pelvic examination, colposcopy, optical coherence tomography (OCT), and semistructured, qualitative interviews. Additional requirements included abstinence (for approximately 16 days) and twice daily vaginal product use (for 5.5 days). Interviews were audio-recorded, transcribed, and analyzed using framework analysis. Themes addressing OCT experiences, acceptability of abstinence, and vaginal product use were examined.

RESULTS

OCT was viewed favorably as an imaging technology. Some women reported feeling the fiber-optic probe "poking" them and more than one-third spontaneously reported feeling pressure or pinching upon rotation of the speculum in connection with the OCT evaluation. Compliance with vaginal gel use was high, but for many women assigned to use a product containing nonoxynol-9 (vs. placebo), the postproduct use examination was more uncomfortable, relative to the initial examination or 1 week following product discontinuation. Nearly all women experienced product leakage; acceptability of leakage varied. Two women were not abstinent and several more found abstinence challenging. Some women involved their partner in decision making regarding trial enrollment. Strategies to remain abstinent included participating when the partner was away, avoiding early intimacy, and engaging in alternative sexual activities.

CONCLUSIONS

Qualitative interviews in early-phase studies provide insights and capture information that would be missed by behavioral inference alone. Understanding participant's experiences is important in order to provide anticipatory guidance and plan future microbicide studies that facilitate adherence with trial requirements.

Pathways of neuronal and cognitive development in children born small-for-gestational age or late preterm

OBJECTIVE

To assess the effects of late small-for-gestational-age (SGA) birth and late prematurity on cognitive outcomes and structural changes in the central nervous system at primary school age, using a novel approach to examine changes in neuronal integrity of the retina.

METHODS

We conducted a cross-sectional study of 347 children aged 6-13 years, including in the analysis only infants born after 34 weeks' gestation. We recorded all perinatal outcomes through a survey of parents. Neuronal damage was evaluated using optical coherence tomography of the retina. In a subgroup of 112 children aged 6-8 years, visuospatial perception was evaluated with the Children's Bender Visual Motor Gestalt Test.

RESULTS

The proportions of SGA and late preterm children were 11.8 and 6.3%, respectively. Prematurity and SGA were simultaneously present in five children. When compared with controls, SGA children showed significantly lower than average retinal nerve fiber layer (RNFL) thickness (94.1 vs 98.8 μm; P = 0.007) and an increased percentage of abnormal Bender scores (27.3 vs 6.2%; P = 0.017) (odds ratio 5.6 (95% CI, 1.2-26.8)). These differences increased when late SGA infants with a birth weight below the 3(rd) percentile were compared with SGA infants with a birth weight between the 3(rd) and 10(th) percentiles and with controls, for RNFL thickness (92.5 vs 94.6 and 98.8 μm, respectively; P = 0.021) and abnormal Bender tests (33.3 vs 25.0 and 6.2%, respectively; P = 0.036). However, no differences were found in retinal structure and visuomotor performance between late preterm and term infants.

CONCLUSIONS

These data suggest that late SGA and late prematurity induce a distinct neuronal pattern of structural changes that persist at school age. Late-onset SGA infants are at increased risk for axonal loss in the retina and present specific visuomotor difficulties.

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.

Axonal loss and cognitive deficits in term infants with normal umbilical artery Doppler born small-for-gestational age

OBJECTIVE

To assess cognitive outcomes and structural changes in the central nervous system, the latter using a novel approach to examine changes in neuronal integrity of the optic nerve, in children at 5-6½ years of age who were born small-for-gestational age (SGA) at term having shown normal umbilical artery (UA) Doppler.

METHODS

We compared neuronal damage, cognitive deficits and visuospatial perception in two cohorts of infants, one born SGA (n = 40) and one born appropriate-for-gestational age (AGA) (n = 39) in weight. Neuronal damage was evaluated using optical coherence tomography (OCT) of the optic nerve. Cognitive deficits were assessed with the Wechsler Preschool and Primary Scale of Intelligence (WPPSI) test. Visuospatial perception was evaluated with Rey-Osterreich Complex Figure (ROCF) tasks.

RESULTS

Children from the SGA group had a significantly thinner average retinal nerve fiber layer (RNFL) compared with those from the AGA group (98.2 vs 104.5 µm, P = 0.012). Children from the SGA group exhibited impaired performance in copy tasks on the ROCF (3.27 vs 3.56, P = 0.036) and a higher rate of suboptimal WPPSI test performance intelligence quotient scores (15% vs 0%; P = 0.025) compared with those from the AGA group.

CONCLUSION

Term infants with normal UA Doppler born SGA are at increased risk for cognitive deficits and axonal loss in the RNFL at the age of 5-6½ years.

Optical endomicroscopy and the road to real-time, in vivo pathology: present and future

Epithelial cancers account for substantial mortality and are an important public health concern. With the need for earlier detection and treatment of these malignancies, the ability to accurately detect precancerous lesions has an increasingly important role in controlling cancer incidence and mortality. New optical technologies are capable of identifying early pathology in tissues or organs in which cancer is known to develop through stages of dysplasia, including the esophagus, colon, pancreas, liver, bladder, and cervix. These diagnostic imaging advances, together as a field known as optical endomicroscopy, are based on confocal microscopy, spectroscopy-based imaging, and optical coherence tomography (OCT), and function as "optical biopsies," enabling tissue pathology to be imaged in situ and in real time without the need to excise and process specimens as in conventional biopsy and histopathology. Optical biopsy techniques can acquire high-resolution, cross-sectional images of tissue structure on the micron scale through the use of endoscopes, catheters, laparoscopes, and needles. Since the inception of these technologies, dramatic technological advances in accuracy, speed, and functionality have been realized. The current paradigm of optical biopsy, or single-area, point-based images, is slowly shifting to more comprehensive microscopy of larger tracts of mucosa. With the development of Fourier-domain OCT, also known as optical frequency domain imaging or, more recently, volumetric laser endomicroscopy, comprehensive surveillance of the entire distal esophagus is now achievable at speeds that were not possible with conventional OCT technologies. Optical diagnostic technologies are emerging as clinically useful tools with the potential to set a new standard for real-time diagnosis. New imaging techniques enable visualization of high-resolution, cross-sectional images and offer the opportunity to guide biopsy, allowing maximal diagnostic yields and appropriate staging without the limitations and risks inherent with current random biopsy protocols. However, the ability of these techniques to achieve widespread adoption in clinical practice depends on future research designed to improve accuracy and allow real-time data transmission and storage, thereby linking pathology to the treating physician. These imaging advances are expected to eventually offer a see-and-treat paradigm, leading to improved patient care and potential cost reduction.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/5372548637202968.

Diagnostic efficacy of backscattering intensity measurements in optical coherence tomography of cervical intraepithelial dysplasia

BACKGROUND AND OBJECTIVES

The aim of this study was to determine the diagnostic efficacy of backscattering intensity measurements in optical coherence tomography in identifying different grades of cervical intraepithelial dysplasia.

STUDY DESIGN/MATERIALS AND METHODS

OCT images were taken from 153 unsuspicious and suspicious areas of 30 fresh conisation and hysterectomy specimens, evaluated by two blinded investigators using a six-grade classification (normal, inflammation, CIN1, CIN2, CIN3, squamous carcinoma) and later compared to the corresponding histology. Differences between judgments based on either the histology or the OCT images were investigated employing Correspondence Analysis (CA). Further, we explored the extent as to which backscattering intensity profiles of OCT images contained the essential information required for a reliable and valid diagnosis, using Linear Discriminant Analysis (LDA).

RESULTS

The CA of histology- and OCT-based judgments suggests that the diagnostic process may be characterized in terms of two stochastically independent underlying ("latent") variables, the first of them reflecting the definiteness with which CIN classes are identified, the second reflecting a bias towards diagnosing inflammation on the side of the OCT-based judgments. This finding is supported by the results of LDAs, where histology and OCT categorizations differ in particular with respect to the positions of inflammation and CIN1. Possibly, a second canonical variable has to be assumed accounting for the evaluation of carcinoma.

CONCLUSIONS

The systematic differences between histology-based and OCT-based diagnoses suggest that the use of available information is influenced by perceptual and/or cognitive biases. Apart from this it seems that the profiles appear to provide a remarkably large amount of information determining the main course of the diagnostic process.

Validation of an ex vivo human cervical tissue model for optical imaging studies

OBJECTIVE

To establish and validate an ex vivo human cervical tissue model for optical coherence tomography (OCT) studies with special emphasis on investigating time dependent structural changes of the epithelium.

METHODS

Four hundred OCT images were taken from 80 unsuspicious and suspicious areas of 18 fresh conisation specimens immediately after resection (0 hour) and 1, 2, 3, and 4 hours, referred to as waiting times in the following, postoperatively and compared to the corresponding histology. For each 2D-OCT-image, a 1D-intensity profile was generated. The profiles were analyzed with respect to systematic differences which may result from different waiting times, employing discriminant analysis (DA).

RESULTS

The different waiting times do not appear to imply significant differences among the corresponding OCT-images as represented by the intensity profiles.

CONCLUSION

We conclude that the proposed cervical tissue model appears to be applicable for ex vivo OCT studies.

Objective perspective in colposcopy

Colposcopy is a widely used diagnostic procedure, primarily in the assessment of women with abnormal cervical cytology. It is used by appropriately trained individuals using techniques that allow a full assessment of the abnormality and plan for further investigation or treatment. Certain key features are specifically looked for, and a colposcopic impression formed. Using a systematic approach to the colposcopic assessment can improve the diagnostic accuracy. In this chapter, we review various factors and meta-analyses in relation to the diagnostic performance of colposcopy. Newer technologies are being developed that will assist the clinician in assessing the colposcopic changes. Quality assurance of the training and practise of colposcopy is important to maintain appropriate management for women with cytological abnormalities.

Recent advances in optical imaging for cervical cancer detection

Cervical cancer is one of the most common and lethal gynecological malignancies in both developing and developed countries, and therefore, there is a considerable interest in early diagnosis and treatment of precancerous lesions. Although the current standard care mainly based on cytology and colposcopy has reduced rates of cervical cancer morbidity and mortality, many lesions are still missed or overcalled and referred for unnecessary biopsies. Optical imaging technologies, spectroscopy approaches and high-resolution imaging methods are anticipated to improve the conventional cervical cancer screening providing in vivo diagnosis with high sensitivity and specificity. Their concept is that morphologic and biochemical properties of the cervical tissue are altered in response to its malignant transformation. In addition, contrast agents that target against specific neoplastic biomarkers can enhance the effectiveness of this new technology. Due to the unprecedented growth of these optical techniques accompanied probably by favorable cost-effectiveness, the primary detection of premalignant lesions may become more accessible in both the developing and the developed countries and can offer see-to-treat workflows and early therapeutic interventions.