Instruments and technique of the Echo-endoscopy

Echo-endoscopies use radial and linear equipment, depending on the lesion’s characteristics or the test requirements.

The radial echo-endoscope presents an oblique view and a 360° ultrasonic image, achieving a complete diagnostic study.

The equipment uses 5-6-7, 5, and 10 MHz frequencies, always located at the tip of the equipment. The radial echo-endoscope is most commonly used for diagnostic tests, and this equipment is utilised to provide an ultrasound identifying five layers of the walls of the entire digestive tract.

1. The first hyperechoic layer is the most superficial part of the gastric mucosa.

2. The second hyperechoic layer is the deepest part of the mucosa, and can be correlated to the muscle mucosa.

3. The third hyperechoic layer is the submucosa layer.

4. The fourth hyperechoic layer is the muscle layer.

5. The fifth hyperechoic layer is the serous or adventitious layer.

The linear echo-endoscopy uses 5-6-7, 5-10-12 MHz frequencies and presents an oblique endoscopic view with a 180° ultrasonic image aimed at directing the puncture needle and providing detailed images of all the structures that surround the area. This is the most technologically advanced equipment used for performing therapeutic echo-endoscopies.

It has a wide, 3.7 mm diameter work channel that allows for the use of puncture techniques with 25G, 22G, or 19G suction needles, and an elevator to move the needle forwards with great precision in order to take samples of lesions on or adjacent to walls, such as the mediastinum, pancreas, adrenal gland, etc. Similarly, it is also possible to drain cysts o pancreatic pseudocysts, and other therapeutic procedures.

The echo-endoscopy, or EUS, is performed with two different echo-endoscopes:

1-    Diagnostic radial echo-endoscope.
2-    Therapeutic linear echo-endoscope.
2a-  Interventionist linear echo-endoscope with PAAF.
2b-  Therapeutic linear echo-endoscope.