Gastroenterology: between capsule endoscopy and AI

Gastrointestinal endoscopy is the core diagnostic and therapeutic procedure in gastroenterology. It allows direct visualization of the gastrointestinal tract, the removal of tissue samples, and immediate intervention if necessary. The method is a versatile interventional procedure that is used for everything from early detection to minimally invasive therapy.

The term endoscopy generally refers to the examination of body cavities and hollow organs with optical instruments. In gastroenterology, it refers to the direct examination of the gastrointestinal tract. This term must be distinguished from minimally invasive surgical procedures where endoscopy refers to procedures such as laparoscopy, or the introduction of probes through the abdominal wall, and arthroscopy, in which instruments are inserted through small incisions to typically examine and treat joint issues.

All gastrointestinal endoscopies are based on a flexible video endoscope – a thin, flexible tube with an integrated camera and light source at the tip. The camera transmits real-time images so that the treatment team can directly assess the mucous membrane of the digestive tract.

The endoscope has a working channel through which instruments can be inserted: biopsy forceps for tissue sampling, snares for polyp removal, clips for hemostasis, or injection needles. This allows diagnostic endoscopy to become a therapeutic intervention if necessary.

Patients must fast before undergoing a gastroscopy. A complete bowel cleansing using laxatives is required before a colonoscopy. Patients are sedated for the examination. Depending on the procedure, the examination itself takes between ten minutes (gastroscopy) and around 20 to 30 minutes (colonoscopy).

The indications for gastrointestinal endoscopy are broad. Gastroscopy is indicated for persistent upper abdominal discomfort, swallowing disorders, heartburn, gastrointestinal bleeding, and to rule out or confirm inflammation, ulcers, and tumors in the esophagus or stomach.

Colonoscopy is the standard procedure for early detection of colon cancer. It is also indicated for chronic inflammatory bowel diseases (Crohn's disease, ulcerative colitis), unexplained bleeding in the lower gastrointestinal tract, and a family history of the disease.

The focus is on three areas of application:

• Computer-Aided Detection (CADe): AI systems detect mucosal changes suspected of being polyps during colonoscopy and mark them on the monitor. Commercial systems are clinically available. A network meta-analysis from 2025 shows that all CADe systems examined significantly increase the adenoma detection rate (ADR) compared to standard colonoscopy.
• Computer-Aided Diagnosis (CADx): Beyond pure detection, CADx systems classify lesions and distinguish between adenomas and hyperplastic polyps, for example. However, recent studies (German website) show mixed results in terms of clinical benefit.
• Capsule endoscopy evaluation: In capsule endoscopy, an examination generates up to 50,000 individual images. AI-supported diagnostic systems (German website) assist in the evaluation and reduce the time required while increasing the detection rate of relevant findings.

Capsule endoscopy is used to diagnose small intestine diseases, as the small intestine cannot be reached with a conventional endoscope. The most important indication is the investigation of mesenteric gastrointestinal bleeding (MGIB), i.e., a source of bleeding that could not be identified by gastroscopy (upper GI tract) or colonoscopy (lower GI tract).

In capsule endoscopy, the patient swallows a miniature camera in a pill-shaped capsule. The capsule contains LED lighting, a camera, and a transmitter. It passes through the intestine, continuously photographing the mucous membrane. The images generated are transmitted via radio waves to a recording device worn on the body.

The examination usually takes six to eight hours. The patient can move around freely during this time. A few hours after ingestion, light food is also allowed. The capsule is excreted naturally and is not reused. The treatment team then evaluates the image sequences.

Bowel cleansing is recommended beforehand. If the patient's medical history is unclear, an X-ray or MRI examination is performed before the examination to rule out intestinal narrowing (stenosis) as a contraindication.

The future of capsule endoscopy could then be a "smart pill" that can perform various tasks within the digestive tract.

The following table provides an overview of the most important advantages and disadvantages of capsule endoscopy compared to conventional endoscopy: