In-vivo-Diagnostik von Epithelveränderungen des Oropharynx mittels konfokaler Mikroskopie

Potential Use of Vivascope for Real-Time Histological Evaluation in Endoscopic Laryngeal Surgery

We aimed to assess the feasibility of using confocal laser scanning microscopy (CLSM) for the real-time ex vivo examination of histological samples of laryngeal lesions and to evaluate the correlation between CLSM and definitive histological results. This preliminary study included eight consecutive patients with "suspected" laryngeal lesions who were candidates for endoscopic laryngeal surgery. The obtained samples were evaluated using CLSM and classified as "inadequate" or "adequate" (high- and low-grade dysplasia, in situ and invasive carcinoma, positive surgical margin, and inflammatory outbreaks). CLSM showed the macro image in all cases and generated a digital version. All the samples were defined as adequate during CLSM and confirmed at histopathology: low-grade dysplasia (n = 5), low- and high-grade dysplasia (n = 2), and high-grade dysplasia (n = 1). Four samples had an involved resection margin, and three samples revealed the presence of inflammatory outbreaks. CLSM can be applied to larynx pathology with excellent agreement with final histological results.

Intraoperative free margins assessment of oropharyngeal squamous cell carcinoma with confocal laser endomicroscopy: a pilot study

PURPOSE

This pilot study aimed to assess the feasibility of intraoperative assessment of safe margins with confocal laser endomicroscopy (CLE) during oropharyngeal squamous cell carcinoma (OPSCC) surgery.

METHODS

We included five consecutive patients confirmed OPSCC and planned tumor resection in September and October 2020. Healthy appearing mucosa in the marginal zone, and the tumor margin, were examined with CLE and biopsy during tumor resection. A total of 12,809 CLE frames were correlated with the gold standard of hematoxylin and eosin staining. Three head and neck surgeons and one pathologist were asked to identify carcinoma in a sample of 169 representative images, blinded to the histological results.

RESULTS

Healthy mucosa showed epithelium with uniform size and shape with distinct cytoplasmic membranes and regular vessel architecture. CLE optical biopsy of OPSCC demonstrated a disorganized arrangement of variable cellular morphology. We calculated an accuracy, sensitivity, specificity, PPV, and NPV of 86%, 90%, 79%, 88%, and 82%, respectively, with inter-rater reliability and κ-value of 0.60.

CONCLUSION

CLE can be easily integrated into the intraoperative setting, generate real-time, in-vivo microscopic images of the oropharynx for evaluation and demarcation of cancer. It can eventually contribute to a less radical approach by enabling a more precise evaluation of the cancer margin.

In vivo confocal microscopy for the oral cavity: Current state of the field and future potential

Confocal microscopy (CM) has been shown to correlate with oral mucosal histopathology in vivo. The purposes of this review are to summarize what we know so far about in vivo CM applications for oral mucosal pathologies, to highlight some current developments with CM devices relevant for oral applications, and to formulate where in vivo CM could hold further application for oral mucosal diagnosis and management. Ovid Medline® and/or Google® searches were performed using the terms 'microscopy, confocal', 'mouth neoplasms', 'mouth mucosa', 'leukoplakia, oral', 'oral lichen planus', 'gingiva', 'cheilitis', 'taste', 'inflammatory oral confocal', 'mucosal confocal' and 'confocal squamous cell oral'. In summary, inclusion criteria were in vivo use of any type of CM for the human oral mucosa and studies on normal or pathological oral mucosa. Experimental studies attempting to identify proteins of interest and microorganisms were excluded. In total 25 relevant articles were found, covering 8 main topics, including normal oral mucosal features (n=15), oral dysplasia or neoplasia (n=7), inflamed oral mucosa (n=3), taste impairment (n=3), oral autoimmune conditions (n=2), pigmented oral pathology/melanoma (n=1), delayed type hypersensitivity (n=1), and cheilitis glandularis (n=1). The evidence for using in vivo CM in these conditions is poor, as it is limited to mainly small descriptive studies. Current device developments for oral CM include improved probe design. The authors propose that future applications for in vivo oral CM may include burning mouth syndrome, intra-operative mapping for cancer surgery, and monitoring and targeted biopsies within field cancerization.

Oral mucosa optical biopsy by a novel handheld fluorescent confocal microscope specifically developed: technologic improvements and future prospects

OBJECTIVE

This pilot study evaluated the baseline effectiveness of a novel handheld fluorescent confocal microscope (FCM) specifically developed for oral mucosa imaging and compared the results with the literature.

STUDY DESIGN

Four different oral sites (covering the mucosa of the lip and of the ventral tongue, the masticatory mucosa of the gingiva, and the specialized mucosa of the dorsal tongue) in 6 healthy nonsmokers were imaged by an FCM made up of a confocal fiberoptic probe ergonomically designed for in vivo oral examination, using light at the wavelength of 457 nm able to excite the fluorophore acriflavine hydrochloride, topically administered. In total, 24 mucosal areas were examined.

RESULTS

The FCM was able to distinctly define epithelial cells, bacterial plaque, and inflammatory cells and to image submucosal structures by detecting their intrinsic fluorescence.

CONCLUSIONS

When compared with other devices, this FCM allowed the user to image each oral site at higher magnification, thus resulting in a clearer view.

Rigid confocal endoscopy for in vivo imaging of experimental oral squamous intra-epithelial lesions

BACKGROUND

A rigid confocal endoscope has been developed to assess the oral squamous epithelium of mice and to determine sensitivity, specificity, and accuracy of this new technology.

METHODS

This endoscope is connected to the commercially available Heidelberg Retina Tomograph (HRT). HRT is a device with a 670-nm diode laser designed to acquire topographical measurements of the optic nerve head. Real-time rigid confocal endoscopy is demonstrated by imaging the epithelial lesions of a mice model. Six-week-old male C57Bl/6 mice were randomly divided into a non-treated group (n = 10) and into a 4-nitroquinoline 1-oxide (4-NQO)-treated group (n = 50). In the 4-NQO-treated group, the mice obtained 4-nitroquinoline 1-oxide in the drinking water (100 microg/ml) to induce tumourigenesis in the mouse tongue. The 4-NQO-solution was diluted in the drinking water for mice. After an 8-16-week carcinogen treatment with 4-NQO (ad libitum), mouse tongues were dissected within 3 h after CO(2) overdose. After confocal microscopy of all lesions of the tongue, conventional histopathological investigation was performed.

RESULTS

The inter-rater reliability for the two observers of the confocal microscopic findings was found to be Kappa = 0.59 (P < 0.001). The penetration depth varied in the healthy tissue of the underside of the tongue throughout this study and was measured between 104 and 240 microm. In keratotic lesions, the penetration depths were diminished and varied between 80 and 140 microm. Strong keratinization inhibits the evaluation of the epithelium. For differentiation between low-grade and high-grade squamous intra-epithelial lesions, a sensitivity and specificity of 73% and 88% was reached.

CONCLUSIONS

The animal experiment with this non-invasive new technology indicates that this imaging technology facilitates the detection of pre-cancerous lesions of the underside of the oropharynx. Human studies on oropharyngeal and laryngeal lesions are needed to prove the applicability of this method in the field of otorhinolaryngology.

Change of the human taste bud volume over time

OBJECTIVE

The specific aim of this study is to measure the taste volume in healthy human subjects over a 2.5-month period and to demonstrate morphological changes of the peripheral taste organs.

MATERIAL AND METHODS

Eighteen human taste buds in four fungiform papillae (fPap) were examined over a 10-week period. The fungiform papillae investigated were selected based on the form of the papillae or the arrangement of surface taste pores. Measurements were performed over 10 consecutive weeks, with five scans in a day once a week. The following parameters were measured: height and diameter of the taste bud, diameter of the fungiform papilla and diameter of the taste pore.

RESULTS

The findings of this exploratory study indicated that (1) taste bud volumes changed over a 10-week period, (2) the interval between two volume maxima within the 10-week period was 3-5 weeks, and (3) the diameter of the fPap did not correlate with the volume of a single taste bud or with the volume of all taste buds in the fPap within the 10-week period.

CONCLUSIONS

This exploratory in vivo study revealed changes in taste bud volumes in healthy humans with age-related gustatory sensitivity. These findings need to be considered when studying the effect of denervation of fungiform papillae in vivo using confocal microscopy.