Contact Endoscopy in ENT

🔬 Contact Endoscopy in ENT

📝 Definition of Contact Endoscopy

Contact endoscopy is a non-invasive, in vivo optical diagnostic technique that allows in situ examination of the cellular architecture of the superficial layers of the mucosal epithelium.

• It helps diagnose early dysplastic changes in premalignant conditions and malignancy

• ❌ It is not a replacement for biopsy and histopathology; it is only an adjunct investigation used for screening

🕰️ History of Contact Endoscopy

Subsequent Developments

• Improved optical magnification, from 1x to 60x and 150x
• Use of vital stains such as methylene blue
• Integration with microlaryngoscopy, office-based endoscopy and early cancer detection protocols

🔍 Principle of Contact Endoscopy

A rigid endoscope is placed in direct contact with the mucosal surface of the upper aerodigestive tract, allowing in vivo microscopic visualization of the epithelial cells, usually after application of a vital stain such as methylene blue.

What is the Mechanism by which Contact Endoscopy works?

What is the depth of visualisation in Contact endoscopy?

🔧 Equipment Required

1- Rigid Contact Endoscope

• 0 degree or 30 degree scopes are used
• Magnification of 1x, 60x and 150x

What are the different endoscopes commonly used in Contact endoscopy?

⭐ A control near the proximal ocular end allows a change of magnification from 60x to 150x and also controls the focus.

2- Light Source

• Xenon light source, or LED

3- Camera and Monitor

For recording the procedure.

4- Staining Agents

• Methylene blue (most commonly used)
• Toluidine blue

Why is Methylene blue the most commonly used agent in Contact endoscopy?

🔍 Procedure of Contact Endoscopy

Anaesthesia

A- Observation of the Vessels (Microvascular Circulation)

B- Observation of the Superficial Cells of the Epithelium

Describe the procedure of Contact Endoscopy in detail.

How can Contact endoscopy be combined with Narrow Band Imaging?

How long does Methylene blue coloration last?

✅ Applications of Contact Endoscopy in ENT

Primarily used for in vivo microscopic evaluation of the mucosal epithelium, for the early detection, differentiation and follow-up of lesions of the upper aerodigestive tract.

What are the applications of Contact endoscopy in Larynx, oral cavity, nasal cavity?

What are the intraoperative applications of Contact endoscopy in ENT?

⚠️ Contact endoscopy is an adjunct to histopathology, not a replacement.

What are the Advantages of Contact Endoscopy?

What are the Limitations of Contact Endoscopy?

🔬 Normal Patterns on Contact Endoscopy

1- Normal Squamous Epithelium

• Cells have a polyhedric shape, in continuity with each other
• Nuclei are round and dark
• Cytoplasm has a light blue coloration
• Regular nuclear cytoplasmic ratio
• Homogeneous general morphological pattern

2- Normal Ciliated Epithelium

• Nuclei are round and dark
• Cytoplasmic limits are difficult to define
• Nuclei lie very close to each other, creating a high density of nuclei per optic field
• Filamentous structures (bundles of cilia) are displaced by the endoscope
• Bundles vary in size and are more prominent at the level of the nasal and nasopharyngeal mucosa

What does the transition from Squamous to Ciliated Epithelium look like in Contact Endoscopy?

3- Mucosal Vessels

The most superficial microvascular network lies immediately below the basal membrane.

⭐ The morphology of the vascular network depends on the topography and function of the mucosa.

What are the sites where you see the vessels running perpendicular to the surface?

What is the finding seen on Contact Endoscopy in Chronic Inflammation?

What is the finding seen on Contact Endoscopy in Fungal Infections?

What is the finding seen on Contact Endoscopy in Keratosis?

What is the finding seen on Contact Endoscopy in Dysplasia?

What is the finding seen on Contact Endoscopy in Tumour?

What is the finding seen on Contact Endoscopy in Papilloma?

🧠 Viva Pearls

• Contact endoscopy is a non-invasive, in vivo optical diagnostic technique for the superficial mucosal epithelium.
• It is an adjunct to histopathology, never a replacement.
• First described by Desormeaux in 1865 during cystoscopy.
• Adapted to the laryngeal and upper aerodigestive tract mucosa by Andrea and Dias in 1995.
• Magnifications available are 1x, 60x and 150x.
• Contact endoscopy can be combined with narrow band imaging to visualize deeper vessels.
• Normal squamous epithelium shows polyhedric cells with round dark nuclei and light blue cytoplasm.
• At the vocal cords, vessels run parallel and are connected by transverse anastomotic vessels.

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