Endoscopic ultrasound

Endoscopic ultrasound (EUS, of endoscopic ultrasound ) is a not externally conducted through the skin, but from the inside ultrasound ( sonography ). The ultrasound head is by means of special equipment (usually endoscopes) reacted directly with inner surfaces (such as the lining of the esophagus ) in contact. There then arises an ultrasound image.

Compared to the ultrasound through the outer skin, this method has the advantage that thereby is closer to the target organ, the ultrasound head and thus can be shown in more detail and sharper or its representation is at all possible. To allow an even better representation is a balloon at the tip of the endoscope, which is filled with water. This provides a 360 ° view is possible. Other devices have an elongated probe with the ability to take test. Endosonography allows the first place the representation of internal organs in large animal medicine.

Depending on the application, different devices are used to endosonography. To examine the esophagus, stomach, duodenum and subsequent bronchial a special flexible endoscope is used, whose top is in addition to the optics is a miniaturized ultrasound probe. This Endoscopic ultrasound endoscope is slightly thicker than a normal endoscope.

The gastroenterological endoscopic ultrasonography has been established over the last 20 years as a key component in the diagnosis of benign and malignant processes in the esophagus, mediastinum, stomach, gall bladder, pancreas and rectum. Increasingly also spread endosonographically controlled interventional techniques. Here, a puncturing needle is passed through the Endosonographiegerät and extracted under ultrasound guidance, a sample from a diagnosis. Endosonography is next to endoscopic skill requires subtle knowledge of anatomy and ultrasound anatomy and is considered one of the most difficult -to-learn endoscopically assisted methods.

Endoscopic ultrasonography in the context of other research methods

The following test methods may be supplemented by a endosonography:

  • Esophagogastroduodenoscopy duodenoscopy
  • Bronchoscopy
  • Rectoscopy
  • Vaginal ultrasound
  • Endoscopic retrograde cholangiopancreatography (ERCP ), but merely as Minisondenendosonographie, see below

Miniprobe endosonography

Related to endosonography are Miniprobe systems. These are tools which can be pushed, eg by means of a so-called biopsy channel. They have a much thinner probe than with the conventional endosonography. However, the radius of penetration of the ultrasound is lower ( penetration depth of the miniprobe is limited to about 3 cm). In contrast to conventional endosonography you work here at fixed frequencies (5/7, 5/10/12/20/25 MHz). Particularly suitable is the Miniprobe endosonography for example for a detailed analysis of a polyp or to estimate the penetration depth of a tumor.

A mini probe endoscopic ultrasonography of the last part of the bile duct ( common bile duct ) as part of an ERCP is called intraductal ultrasonography ( IDUS ).

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