Small bowel imaging according to Sellink (synonym: enteroclysma according to Sellink) is an examination procedure for visualizing the small bowel, which is used primarily in cases of inflammatory processes and their complications (e.g., stenoses). The small intestine is the largest and longest organ of the human body and is largely responsible for the supply of nutrients (macro- and micronutrients; vital substances) to the organism. Because the small intestine is very difficult to examine endoscopically, double-contrast radiographic examination is the primary imaging modality. However, it should be noted that computed tomography (CT) and magnetic resonance imaging (MR-Sellink) are also becoming more prominent in this area.
Indications (areas of application)
- Briden – scarred or connective tissue adhesion strand, for example, on the loops of the small intestine.
- Inflammatory processes in the small intestine
- Diverticula – sac-shaped protrusions of the small intestine wall; if the diverticula occur in large numbers, this is diverticulosis
- Malformations
- Fistulas – as a result of inflammation can form connection between two hollow organs or intestinal loops.
- Lymphoma – tumor of the lymphocytes (immune cells).
- Malrotation – disturbance of intestinal rotation (developmental process in which the organ rotates in position) during embryonic development.
- Meckel’s diverticulum – protrusion of the ileum (scimitar or hip intestine; part of the small intestine), representing a remnant of the embryonic yolk duct (omphaloenteric duct)
- Crohn’s disease – chronic inflammatory bowel disease.
- After intestinal resection (surgical removal of sections of the small intestine).
- Metabolic diseases
- Stenoses (constrictions)
- Tumors
- Unexplained diarrhea (diarrhea)
- Unclear gastrointestinal (gastrointestinal) bleeding.
- Indigestion
- Celiac disease (gluten-induced enteropathy)
The procedure
The patient must be absolutely fasting before the examination. This means neither eating, drinking nor smoking is allowed. First, a probe is advanced transnasally or orally through the esophagus (food pipe), stomach, and duodenum (duodenum) to the flexura duodenojejunalis (transition from the duodenum (duodenum) to the jejunum (empty intestine/small intestine)). Here, the contrast medium is now injected via an electric pump. Since this is a double-contrast examination, a barium sulfate–water mixture (positive contrast agent) is applied first. Then, a methyl cellulose-water mixture, rather than air, is administered as the negative contrast agent. While the barium sulfate attaches to the wall of the small intestine so that the mucosal relief is visualized, the methyl cellulose serves to unfold and openly stretch the loops of the small intestine. The entire examination is documented by fluoroscopy. The small intestinal loops then appear transparent on the images. Two phases result from the temporal sequence of contrast agent administration: The methylcellulose phase primarily enables better recognition of anatomical or morphological changes in the small intestine and its mucosa. The barium phase is used to detect motility disturbances (disturbances in the intrinsic movement of the intestine) and to assess intestinal peristalsis:
- Normal intestinal peristalsis
- Pendulum peristalsis – the intestinal contents oscillate back and forth, this may indicate, for example, an ileus (intestinal obstruction).
- Obstruction peristalsis – a stenosis leads to increased contraction of the intestinal wall or lumen dilatation directly in front of the narrowing
- Hypoperistalsis – decreased intrinsic movement.
- Hyperperistalsis – increased proper motion with accelerated passage of the contrast agent.
Further notes
- In Sellink magnetic resonance imaging (MR-Sellink), the entire small intestine is filled with the negative contrast agent mannitol via a duodenal probe. MRI of the abdomen and pelvis is then performed with additional intravenous administration of contrast agent (gadolinium). The procedure visualizes inflammation and detects stenoses and fistulas.
