jcRigid confocal endoscopy for in vivo imaging of

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

Farahati B , Stachs O , Prall F , Stave J , Guthoff R , Pau HW , Just T . ` Rigid confocal endoscopy for in vivo imaging of experimental oral squamous intra-epithelial lesions Date : 16/03/11

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` Successful treatment of cancer is highly dependent on the stage at which diagnosis occurs. Early diagnosis, when the disease is still localized at its origin, results in very high cure rates—even for cancers that typical have poor prognosis. Unfortunately, many cancers are not found until later stages due to inadequate diagnostic techniques. Approximately 90% of cancers arise from the epithelial cells that cover organs. Development of surgical devices that can better interrogate epithelial surfaces for abnormalities would enable earlier detection of cancer and significant gains in overall patient survival.

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confocal microscopy, a more recent innovation, is also being used with greater frequency because it can directly image bulk sections of tissue with high clarity. Bright field images of bulk tissue appear very blurry due to simultaneous collection of out of focus planes. However, confocal images of bulk tissue are sharp because the microscope only collects light from in focus planes; light from out of focus planes is rejected.

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Since the confocal microscope alleviates the need for cutting tissue into thin sections, it has significant potential as an in-vivo imaging device that could supplant biopsies.

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Thus, the confocal microendoscope system’s ability to resolve cellular detail indicates that it would be a useful tool to improve the detection of dysplasia and adenocarcinoma in-vivo. Any lumen or organ that is endoscopically or laparoscopically accessible is a suitable candidate for microendoscope imaging of the epithelium.

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Abstract 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.

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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

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Rigid endoscopes are usually much shorter than flexible endoscopes. They are often used to look at the surface of internal organs, and may be inserted through a small cut in the skin. Gas or fluid is sometimes used to move the surface tissues of organs in order to see them more clearly. Rigid endoscopes are commonly used to examine the joints.

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Thus, Endoscopy allows doctors to check for irritation, ulcers, inflammation and abnormal tissue growth in the internal organs. It can be used to close off a blood vessel or remove small growths.

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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..

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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

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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 .

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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.

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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 .