Contact endoscopy of the larynx: a quantitative study

Diagnostic Assessment (Imaging) and Staging of Laryngeal Cancer

Diagnosis of larynx cancer relies on a detailed history and physical and objective assessment with endoscopy and imaging. Endoscopy is needed to assess for vocal fold function that directly affects staging. Computed tomography and MRI can be used to assess for tumor extent in relation to intra- and extra-laryngeal structures, especially paraglottic and pre-epiglottic space involvement as well as cartilage invasion. Accurate staging is critical for subsequent treatment decision-making regarding larynx preservation.

Interrater variation of vascular classifications used in enhanced laryngeal contact endoscopy

PURPOSE

Combined use of contact endoscopy (CE) and Narrow Band Imaging (NBI, Olympus^®) is suggested for the visualization of specific vascular changes indicative of glottic neoplasia. We investigated the interrater reliability and agreement in 3 recognized classification systems of vascular changes applied to images from CE + NBI in patients suspected for glottic neoplasia.

METHODS

Six experienced head and neck surgeons familiar with NBI rated 120 images obtained by CE + NBI by 3 classification systems of vascular changes as suggested by Ni et al. (N-C), Puxeddu et al. (P-C), and the European Laryngological Society (ELS-C). Three raters were experienced in CE, and three raters had only limited experience with CE. Crude agreement and Fleiss' kappa with 95% confidence interval were estimated for all 6 raters, and for the 2 levels of expertise for each original classification system and for dichotomized versions of the N-C and the P-C based on suggested neoplastic potential.

RESULTS

The interrater crude agreement and the corresponding kappa values for the ELS-C were good and significantly higher than those for the N-C and P-C for all raters, irrespective of the level of experience with CE (p < 0.0001). There were no significant differences between the N-C and the P-C (p = 0.16). Kappa was considerably improved for both the N-C and the P-C to a level not different from the ELS-C (p = 0.21-0.71) when their 5 original categories were pooled into dichotomized classifications.

CONCLUSION

Difficulties in reliably classifying vascular changes in CE + NBI are evident. Two-tier classification systems are the most reliable.

Contact endoscopy for detection of residual or recurrent disease after radiotherapy for squamous cell carcinoma of the upper aerodigestive tract

OBJECTIVE

The aim of this study was to evaluate contact endoscopy in detecting local treatment failures post-radiotherapy in squamous cell carcinoma of the upper aerodigestive tract.

METHOD

A total of 135 consecutive patients with suspected residual or recurrent cancer after definitive radiotherapy underwent contact endoscopy before biopsy. Contact endoscopy findings were compared with histopathological examination findings. Contact endoscopy could not be completed in 7 patients (5.9 per cent) and histopathological examination was inconclusive in 5 patients (3.7 per cent). The findings of the remaining 123 patients were compared.

RESULTS

The sensitivity, specificity and accuracy of contact endoscopy were 88.75, 88.72 and 86.99 per cent, respectively, with similar results across various sites of upper aerodigestive tract. Inter-observer kappa value was 0.86 (95 per cent confidence interval: 0.79-0.93). The intra-observer kappa value was 0.93 (95 per cent confidence interval: 0.87-1.00) for the first observer and 0.95 (95 per cent confidence interval: 0.90-1.00) for second and third observers.

CONCLUSION

Contact endoscopy showed the same high sensitivity and specificity with low inter- and intra-observer variability in detecting post-radiotherapy failures in cancer of the upper aerodigestive tract as has been shown in non-irradiated tissues in earlier studies.

Contact Endoscopy of mucosal lesions of oral cavity - Preliminary experience

BACKGROUND

Contact Endoscopy is a non invasive tool to visualise alterations in cell architecture in vivo. In this study we investigated the diagnostic accuracy of Contact Endoscopy in detecting malignancy in oral mucosal lesions.

METHODS

76 patients with oral mucosal lesions requiring biopsy were included. Contact Endoscopy was performed by Otolaryngologist before biopsy and findings recorded. The lesion was then biopsied and sent for histopathological examination by Pathologist who was blinded to Contact Endoscopy findings. Findings of Contact Endoscopy were compared with histopathological findings taking the latter as the gold standard. Two biopsies were reported as 'inconclusive' on histopathological examination and hence excluded from the final analysis. Data of the remaining 74 patients is presented here.

RESULTS

Clinically lesions were diagnosed as ulcero-proliferative lesions in 34 patients, Leukoplakia in 19, Erythroplakia in 9, Lichen planus in 5 and Submucous fibrosis in 7 patients. Histopathological examination revealed presence of malignancy in 97.06% of ulcero-proliferative mucosal lesions, 10.53% of leukoplakia and 33.33% of erythroplakia while corresponding figures on Contact Endoscopy were 94.12%, 5.26% and 11.11% respectively. No malignancy was detected in lichen planus and submucous fibrosis by either technique. When compared with histopathological examination, CE showed sensitivity of 84.21%, specificity of 94.44% and accuracy of 89.19%. No adverse effects on the patients were seen due to the procedure or stain.

CONCLUSION

Contact Endoscopy may be useful in determining cellular structure in vivo without biopsy to detect oral malignancy early. Further studies are suggested.

Contact endoscopy as a novel technique in the detection and diagnosis of oral cavity and oropharyngeal mucosal lesions in the head and neck

Objective:

We aimed to investigate the diagnostic accuracy of contact endoscopy in evaluating oral and oropharyngeal mucosal lesions.

Methods:

Between January 2010 and December 2011, 34 patients with lesions of the oral and oropharyngeal mucosa were enrolled in the study. Comparison between initial contact endoscopy results and ‘gold standard’ tissue biopsy was undertaken.

Results:

Nine patients had histologically confirmed squamous cell carcinoma, 2 had carcinoma in situ, 3 had dysplastic lesions and 20 patients had various benign lesions. Contact endoscopy demonstrated sensitivity and specificity of 89 and 100 per cent respectively in the evaluation of malignant lesions. Benign lesions were correctly categorised in 50 per cent of cases (10/20). The video images from contact endoscopy could not be interpreted in six cases.

Conclusions:

Contact endoscopy demonstrates high sensitivity and specificity in the imaging of malignant lesions with reduced reliability in the evaluation of benign lesions. Significant shortcomings also exist in the design of current technology that we believe represent a significant barrier to the reliable collection of useful video data.

Optical and molecular techniques to identify tumor margins within the larynx

Failure to remove tumor cells from the larynx significantly increases the risk of local recurrence following surgical excision. Healthy tissue must be preserved to optimize long-term vocal and swallowing function. It is essential to accurately distinguish between healthy mucosa, dysplasia, and invasive carcinoma. Optical and molecular examining technologies have been developed to improve tumor margin identification in vivo. We aimed to review the efficacy of these technologies. Published articles were identified using MEDLINE, EMBASE, and Cochrane central register of controlled trials (CENTRAL). Randomized clinical trials are required to establish the benefit to patients and cost to the health service of using 5-aminolevulinic acid (ALA)-induced fluorescent imaging, contact endoscopy, and optical coherence tomography (OCT). Furthermore, primary research is required to validate other techniques, such as confocal endomicroscopy and Raman spectroscopy, and to develop their clinical applications in the larynx.

Contact endoscopy as a novel technique in the detection and diagnosis of mucosal lesions in the head and neck: a brief review

Background. There are a variety of described noninvasive optical detection techniques for evaluation of head and neck mucosal lesions. Contact endoscopy is a promising method of in vivo microscopic examination whereby a rigid telescope is placed on a previously dye-stained mucosa allowing evaluation of the superficial cell layers of the epithelium. This technique produces real-time, magnified images of cellular architecture of surface mucosa comparable to histology without the need for biopsy. In this review, we will briefly summarize the efficacy of CE in the detection of precancerous and cancerous mucosal lesions and its potential as a novel technique in early diagnosis, monitoring, and preoperative assessment of mucosal lesions of the head and neck. Methods. PUBMED, MEDLINE, and COCHRANE search revealed five prospective articles on contact endoscopy for the diagnosis of mucosal lesions in the head and neck. Results. The literature search yielded five prospective studies examining contact endoscopy for the diagnosis of benign versus malignant head and neck mucosal lesions. These reported a sensitivity and specificity of 77-100%, specificity of 66-100% and an accuracy of 72-92%. Conclusion. Contact endoscopy is a promising optical technology that may be a useful adjunct in the evaluation and diagnosis of benign and malignant head and neck mucosal lesions. Future prospective randomized double-blind studies of this detection method are required.

Evaluation of inverted papilloma and squamous cell carcinoma by nasal contact endoscopy

BACKGROUND

Contact endoscopy (CE) was initially described as a method used in the analysis of uterine and vocal folds histology. The first nasal cavity CE studies achieved promising results regarding its use for the differentiation between benign and malignant lesions, considering that biopsy might cause some complications, especially bleeding. This study described and compared the findings of CE on inverted papilloma and nasosinusal squamous cell carcinoma (SCC) and tested the effectiveness of this exam as a noninvasive method for in vivo differentiation between these tumors.

METHODS

The patients included in this study were divided into group A, patients diagnosed with inverted papilloma, and group B, patients diagnosed with SCC. CE results were compared among themselves. CE images were presented to examiners not experienced with the method.

RESULTS

Twenty-two patients were examined, 13 in group A and 9 in group B. The main relevant differences in CE findings between those two groups were corkscrew vessels, presence of mitoses, keratinization and nuclear pleomorphism in carcinoma, and vacuolated cells in papilloma. The examiners were capable of defining the diagnosis of these nasal tumors only based on CE images.

CONCLUSION

CE may be a useful noninvasive exam to be used in the in vivo diagnosis of inverted papilloma and nasosinusal SCC, which may enable better preoperative planning.

Evaluation of young smokers and non-smokers with Electrogustometry and Contact Endoscopy

Background

Smoking is the cause of inducing changes in taste functionality under conditions of chronic exposure. The objective of this study was to evaluate taste sensitivity in young smokers and non-smokers and identify any differences in the shape, density and vascularisation of the fungiform papillae (fPap) of their tongue.

Methods

Sixty-two male subjects who served in the Greek military forces were randomly chosen for this study. Thirty-four were non-smokers and 28 smokers. Smokers were chosen on the basis of their habit to hold the cigarette at the centre of their lips. Taste thresholds were measured with Electrogustometry (EGM). The morphology and density of the fungiform papillae (fPap) at the tip of the tongue were examined with Contact Endoscopy (CE).

Results

There was found statistically important difference (p < 0.05) between the taste thresholds of the two groups although not all smokers presented with elevated taste thresholds: Six of them (21%) had taste thresholds similar to those of non-smokers. Differences concerning the shape and the vessels of the fungiform papillae between the groups were also detected. Fewer and flatter fPap were found in 22 smokers (79%).

Conclusion

The majority of smokers shown elevated taste thresholds in comparison to non-smokers. Smoking is an important factor which can lead to decreased taste sensitivity. The combination of methods, such as EGM and CE, can provide useful information about the vascularisation of taste buds and their functional ability.

The role of computer-assisted analysis in the evaluation of nuclear characteristics for the diagnosis of precancerous and cancerous lesions by contact laryngoscopy

PURPOSE

Contact endoscopy (CE) through the direct contact with the surface of the mucosa enables in vivo visualization of upper epithelial layers. There is a broad spectrum of laryngeal pathologies, as has been confirmed by earlier CE reports. The aim of the study was to resolve some of the limitations of CE through the application of computer-assisted image analysis. Quantitative and qualitative evaluation of nuclei was applied in the diagnosis of precancerous and cancerous lesions.

MATERIALS AND METHODS

Fifty four patients with various laryngeal pathologies were included in the study. Paraffin section histopathology showed 15 benign lesions, 12 precancerous lesions (5 mild and 7 severe dysplasias) and 27 invasive squamous cell cancers (SCC). After staining the mucous with 1% methylen blue, examination with contact endoscope (Karl Storz, Germany) connected to the C-7070 Wide Zoom Olympus high-resolution camera was performed.

RESULTS

The most discriminative parameters were revealed to be as follows: nucleus area (p<0.001), nuclei density index (p<0.001), elongation coefficient (p<0.05), nucleus area to equivalent area ratio (p<0.05). Computer-assisted image analysis composed with data mining techniques is presented for nuclei categorization.

CONCLUSIONS

We established that computer-aided image analysis can indicate, with a high level of reliability, cases of severe dysplasia and carcinoma. By implementing the technique described in this paper, we can substantially increase the sensitivity of CE.

Comparison of contact endoscopy and frozen section histopathology in the intra-operative diagnosis of laryngeal pathology

Andrea et al. were the first to use contact endoscopy in the diagnosis of laryngeal disease, in 1995. This method enables in vivo microscopy of laryngeal mucosa.

In the present study, comparison of contact endoscopy with frozen section histopathology was performed in 142 patients with various diseases of the larynx. Paraffin section histopathology diagnosed 70 benign lesions, 23 precancerous lesions and 49 malignant lesions. Frozen section histopathology showed a sensitivity of 89.8 per cent, a specificity of 98.9 per cent and an accuracy of 95.7 per cent (χ2 = 1.5; p = 0.18). Frozen histopathology diagnosed 45 malignant lesions, including one false positive and five false negative results. Contact endoscopy yielded a sensitivity of 79.59 per cent, a specificity of 100 per cent and an accuracy of 92.95 per cent (χ2 = 8.1; p = 0.002). All malignant lesions diagnosed by contact endoscopy were confirmed by histopathology; contact endoscopy failed to recognise malignant lesions in 10 patients.

Contact endoscopy is preferable to frozen section histopathology as it is noninvasive, provides information on microscopic diagnosis and laryngeal lesion margins, and enables visualisation of the laryngeal mucosa microvasculature. The use of contact endoscopy along with frozen section histopathology improves diagnostic accuracy and allows for operative (or other) therapy to continue according to the results obtained.

The choice of chromogen and reliability of contact rhinoscopy in the irradiated nasopharynx

A cross-sectional randomised single blind study was conducted to assess how concentrations of chromogen (vital stain) and the characteristics of the assessors affect the assessment of contact rhinoscopy. Twenty-eight patients who had undergone external radiotherapy for nasopharyngeal carcinoma were assessed by contact rhinoscopy using 0.5 per cent and 1 per cent methylene blue stain on opposite sides of the nasopharynx. Three independent observers assessed the visual clarity of the 45 contact endoscopic images showing squamous metaplasia according to a visual analogue scale. The intraclass correlation coefficients were 0.916 to 0.957 and 0.839 to 0.964 for intra-observer reliability of assessors in the groups of 0.5 per cent and 1 per cent stains, respectively. The intraclass correlation coefficients for inter-observer reliability of assessors were 0.884 and 0.885 in the groups of 0.5 per cent and 1 per cent stains, respectively. The mean scores of clarity of the cellular details were statistically higher in the group of 1 per cent stain among all assessors. These results showed that the assessment of squamous metaplasia by contact endoscopy is highly reliable irrespective of the clinical experience and knowledge of histopathology of the assessors. One per cent methylene blue should be the vital stain of choice in contact endoscopy.

[Rigid telescopy and contact endoscopy in the diagnosis and surgery of Reinke's oedema--clinical and histological assessment]

We focussed our attention on the use of both rigid telescopy and contact endoscopy in order to assess their effectiveness in the diagnosis and surgery of Reinke's oedema. Changes were observed in a sample of 40 patients, suffering from different stages of Reinke's oedema, who had undergone microlaryngoscopies. For the first time during our laryngological praxis, we discussed a number of parameters that appeared to be significant in the monitoring and detailed evaluation of this vocal fold disease. With contact endoscopy, during the early stages of the disease, the cells and nuclei of normal squamous layered epithelium continued to display uniform morphological features. The appearance of epithelial changes helps to distinguish between different stages of Reinke's oedema, which can be associated with severe inflammation or keratinisation. With latter-stage oedemas, the following was observed: various changes in the blood vessels of the glottis, which when viewed through the endoscope have an unusual "loop-like" or "branching" appearance, as well as elongated and varicose blood vessels, and the build-up of erythrocytes inside atypical capillaries. Both endoscope techniques are non-invasive and very appropriate for precisely diagnosing Reinke's oedema within a relatively short period of time. Rigid telescopy has the advantage of enabling the systematic observation of many details in the large area of both vocal fold mucosae, particularly when access to the larynx is difficult. This enables dynamic monitoring and immediate pathology consultations inside the operating theatre. The special contribution of contact endoscopy is that, both in vivo and in situ, it allows a detailed scanning and mapping to be performed of all cell changes and ofvascularisation throughout the entire mucosa surface. Video-assisted telescopy does not permit a completely first-rate surgical resection of Reinke's oedema, because of unsatisfactory control or insufficient stability of the instrument during the operation using the one-handed method.

3-D optical coherence tomography of the laryngeal mucosa*

Laryngeal carcinoma is one of the commonest primary head and neck malignancy and the need for early identification is very important for successful treatment. Outpatient fibreoptic examination of the larynx is unreliable in differentiating benign, pre-malignant and malignant lesions, and therefore surgeons have to rely on biopsies for a definitive diagnosis. This is an invasive procedure requiring general anaesthesia and may have a detrimental effect on the patient's voice. Conventional imaging modalities (ultrasound, computed tomography and magnetic resonance imaging) have a limited resolution and hence cannot give sufficient information on the extent or nature of laryngeal lesions. The aim of our study is to investigate the feasibility of optical coherence tomography (OCT) in imaging the normal larynx, to lay the foundations for an investigation of its ability to differentiate between benign and malignant disease. Ten tissue specimens from normal larynges were imaged with an 850 nm OCT system that was capable of providing both B-scan (longitudinal or cross-section) images as well as C-scan (en-face or images at constant depth). The en-face OCT mode allowed us to reconstruct 3-D OCT images of the tissue examined. Imaged specimens were processed with standard histopathological techniques and sectioned in the plane of the B-scan OCT images. Haematoxylin-eosin stained specimens were compared with the OCT images thus collected. Preliminary results showed good correlation between OCT images and histology sections in normal tissue.

Observation of tongue papillae by video microscopy and contact endoscopy to investigate their correlation with taste function

OBJECTIVES

Contact endoscopy is a technique used to obtain detailed images of living epithelium in the fields of gynecology, rhinology and laryngology. Video microscopy is useful for observation of the surface of tongue papillae. In the present study, we attempted to apply the contact endoscopy technique together with video microscopy to observe tongue papillae, and to study the correlation between the condition of fungiform papillae and taste function.

METHODS

Ten subjects (3 men, 7 women) were divided into two groups based on the results of a taste examination by electrogustometry. We compared the shape and blood vessels of the papillae between normal taste and taste disorder groups.

RESULTS

In the normal taste group, round shaped papillae and clear blood vessels were observed with both microscopy and contact endoscopy. In the taste disorder group, flat and irregular papillae were observed with microscopy. Blood vessel flow of the papillae was observed to be poor with contact endoscopy.

CONCLUSION

These findings suggested that the images of microscopy and contact endoscopy were related to taste function, and both techniques were useful for evaluating taste function.