LUMA™ Cervical Imaging System

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.

Diagnostic imaging of cervical intraepithelial neoplasia based on hematoxylin and eosin fluorescence

Background

Pathological classification of cervical intraepithelial neoplasia (CIN) is problematic as it relies on subjective criteria. We developed an imaging method that uses spectroscopy to assess the fluorescent intensity of cervical biopsies derived directly from hematoxylin and eosin (H&E) stained tissues.

Methods

Archived H&E slides were identified containing normal cervical tissue, CIN I, and CIN III cases, from a Community Hospital and an Academic Medical Center. Cases were obtained by consensus review of at least 2 senior pathologists. Images from H&E slides were captured first with bright field illumination and then with fluorescent illumination. We used a Zeiss Axio Observer Z1 microscope and an AxioVision 4.6.3-AP1 camera at excitation wavelength of 450–490 nm with emission captured at 515–565 nm. The 32-bit grayscale fluorescence images were used for image analysis.

Results

We reviewed 108 slides: 46 normal, 33 CIN I and 29 CIN III. Fluorescent intensity increased progressively in normal epithelial tissue as cells matured and advanced from the basal to superficial regions of the epithelium. In CIN I cases this change was less prominent as compared to normal. In high grade CIN lesions, there was a slight or no increase in fluorescent intensity. All groups examined were statistically different.

Conclusion

Presently, there are no markers to help in classification of CIN I-III lesions. Our imaging method may complement standard H&E pathological review and provide objective criteria to support the CIN diagnosis.

In Vivo Detection of Rat Colorectal Cancers by using a Dual-Wavelength Excitation Method

Hypoxia is a characteristic feature of solid neoplasms, and insufficient oxygen supply increases cellular nicotinamide adenine dinucleotide (NADH) fluorescence, which is a main component of autofluorescence of the colorectal mucosa. We investigated whether a dual-wavelength excitation method which is optimized for sensing mucosal NADH fluorescence could be applicable to the detection of rat colorectal cancers in vivo. Rat colorectal adenocarcinomas were studied by using fluorescence stereomicroscopy. After autofluorescence images at 470 nm irradiated with dual-wavelength excitation at 365 nm (F365 ex) and 405 nm (F405 ex) were acquired, ratio images were produced by dividing F365 ex by F405 ex: The excitation-emission wavelength pairs in F365 ex and F405 ex were adjusted for acquisition of NADH fluorescence and reference fluorescence. Based on observations from the luminal surface in vivo, F365 ex/F405 ex ratio images indicated a 1.57-fold higher signal value in the cancers than in the surrounding normal mucosa. The signal values in F365 ex/F405 ex ratio images were less mutually related with the hemoglobin concentration index. Small adenocarcinomas (less than 4 mm) could be detected on F365 ex/F405 ex ratio images. The results showed that NADH fluorescence measurement with little interference from tissue hemoglobin is efficient for visualizing rat colorectal cancers in vivo, suggesting that the dual-wavelength excitation method has potential for label-free endoscopic detection of diminutive colorectal neoplasms.

Cervical smear photodiagnosis by fluorescence

OBJECTIVE

Fluorescence is widely investigated and can characterize general changes occurring in the state of the cell and the tissue during physiological and/or pathological processes, but the method has not been adopted for clinical use. We present a photodiagnostic device and a relevant evaluation method fitted to classical screening procedures. This method is based on the discovery of smear content intrinsic fluorescent markers.

BACKGROUND DATA

Meaningful spectral components of cervical smear samples differ from those measured in the entire live cervix. This article deals with the identification of changes in smear spectra in cervicitis and CIN2+ (cervical intraepithelial neoplasia of the second degree or higher) at 355 nm excitation.

METHODS

Methods used in the study: microlaser-induced fluorescence spectroscopy of liquid cytology samples and histological evaluation of the biopsies of the same cervix (and/or only cytological evaluation) was performed for 78 cases. The fluorescence spectra of cervical cytology supernatant sediment were approximated with several Gaussian components. The ratios of the area under each Gaussian component to the whole area under the experimental curve were calculated and compared among histological groups by using the Mann-Whitney test and receiver operating characteristic (ROC) analysis.

RESULTS

The results of this study are a concise summary of the essential features verified by the data: the spectral regions 402-416 nm and 424-438 nm are important for the discrimination of both normal and CIN2+ groups (in terms of sensitivity, specificity, and positive predictive value). The spectral regions 480-515 nm and 595-625 nm are important for the identification of cervicitis.

CONCLUSIONS

Cervical smear autofluorescence diagnostics could be useful for cancer screening at the point of care, in a simple cytology laboratory, and for the monitoring of treatment. We suggest possible fluorophores in the smear content.

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.

Role of optical spectroscopy using endogenous contrasts in clinical cancer diagnosis

Optical spectroscopy has been intensively studied for cancer management in the past two decades. This review paper first introduces the background of optical spectroscopy for cancer management, which includes the advantages of optical techniques compared to other established techniques, the principle of optical spectroscopy and the typical setup of instrumentation. Then the recent progress in optical spectroscopy for cancer diagnosis in the following organs is reviewed: the brain, breast, cervix, lung, stomach, colon, prostate and the skin. Reviewed papers were selected from the PubMed database with keywords combining the terms of individual optical spectroscopy techniques and cancers. The primary focus is on the in vivo applications of optical spectroscopy in clinical studies. Ex vivo studies are also included for some organs to highlight special applications or when there are few in vivo results in the literature. Practical considerations of applying optical spectroscopy in clinical settings such as the speed, cost, complexity of operation, accuracy and clinical value are discussed. A few commercially available clinical instruments that are based on optical spectroscopy techniques are presented. Finally several technical challenges and standard issues are discussed and firm conclusions are made.

Digital colposcopy: ready for use? An overview of literature

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

Optical imaging for cervical cancer detection: solutions for a continuing global problem

Cervical cancer is the leading cause of cancer death for women in developing countries. Optical technologies can improve the accuracy and availability of cervical cancer screening. For example, battery-powered digital cameras can obtain multi-spectral images of the entire cervix, highlighting suspicious areas, and high-resolution optical technologies can further interrogate such areas, providing in vivo diagnosis with high sensitivity and specificity. In addition, targeted contrast agents can highlight changes in biomarkers of cervical neoplasia. Such advances should provide a much needed global approach to cervical cancer prevention.