Computed tomography enterography (CT enterography, CTE) is a medical imaging technique which uses

computed tomography A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...

scanner and

contrast media A contrast agent (or contrast medium) is a substance used to increase the contrast of structures or fluids within the body in medical imaging. Contrast agents absorb or alter external electromagnetism or ultrasound, which is different from radio ...

to examine the

small bowel The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the pa ...

. It was first introduced by Raptopoulos et al. in 1997. CT Enterography can be used to assess a variety of problems involving the small bowel, however it is mainly used to diagnosis and assess severity of

Crohn's disease Crohn's disease is a type of inflammatory bowel disease (IBD) that may affect any segment of the gastrointestinal tract. Symptoms often include abdominal pain, diarrhea (which may be bloody if inflammation is severe), fever, abdominal distension ...

. ''CT enterography'' should not be confused with ''CT enteroclysis''. In CT enterography contrast media is given orally, and in CT enteroclysis contrast media is administered through a

fluoroscopy Fluoroscopy () is an imaging technique that uses X-rays to obtain real-time moving images of the interior of an object. In its primary application of medical imaging, a fluoroscope () allows a physician to see the internal structure and functio ...

-guided positioned nasojejunal tube.

Advantages

CTE provides enough distention of the bowel not present during normal CT imaging to increase the ability to examine in lumen and internal lining of the small intestines. When the small bowel is not properly distended it can be difficult to see if there is a problem in that area. CTE also provides better visualization of extraenteric findings, as well as acute inflammation, of

. These extraenteric findings include, but no limited to,

fistula A fistula (plural: fistulas or fistulae ; from Latin ''fistula'', "tube, pipe") in anatomy is an abnormal connection between two hollow spaces (technically, two epithelialized surfaces), such as blood vessels, intestines, or other hollow or ...

s and

abscess An abscess is a collection of pus that has built up within the tissue of the body. Signs and symptoms of abscesses include redness, pain, warmth, and swelling. The swelling may feel fluid-filled when pressed. The area of redness often extends b ...

es. Additionally, compared with CT enteroclysis, the patient does not need to be sedated for CTE nor requires the invasive step of placing the nasojejunal tube.

Disadvantages

While CTE's main use is in the diagnosis and follow up in

, many of the findings on Crohn's disease found on CTE can be caused by a wide variety of other conditions. Spasm and collapse of the small intestine, which can happen in Crohn's disease, can obscure imaging of that portion of the bowel even with CTE.

Indications

* Suspected small bowel bleeding in a hemodynamically stable patient *

** Initially evaluation and follow up * Unexplained diarrhea * Small Bowel masses ** Malignant ***

Adenocarcinoma Adenocarcinoma (; plural adenocarcinomas or adenocarcinomata ) (AC) is a type of cancerous tumor that can occur in several parts of the body. It is defined as neoplasia of epithelial tissue that has glandular origin, glandular characteristics, or ...

***

Carcinoid A carcinoid (also carcinoid tumor) is a slow-growing type of neuroendocrine tumor originating in the cells of the neuroendocrine system. In some cases, metastasis may occur. Carcinoid tumors of the midgut (jejunum, ileum, appendix, and cecum) ...

***

Lymphoma Lymphoma is a group of blood and lymph tumors that develop from lymphocytes (a type of white blood cell). In current usage the name usually refers to just the cancerous versions rather than all such tumours. Signs and symptoms may include enlar ...

***

Gastrointestinal stromal tumor Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms of the gastrointestinal tract. GISTs arise in the smooth muscle pacemaker interstitial cell of Cajal, or similar cells. They are defined as tumors whose behavior is ...

** Non-malignant ***

Hyperplastic polyp Hyperplasia (from ancient Greek ὑπέρ ''huper'' 'over' + πλάσις ''plasis'' 'formation'), or hypergenesis, is an enlargement of an organ or tissue caused by an increase in the amount of organic tissue that results from cell proliferatio ...

s *** Hamartomatous polyps sencondary to

Peutz–Jeghers syndrome Peutz–Jeghers syndrome (often abbreviated PJS) is an autosomal dominant genetic disorder characterized by the development of benign hamartomatous polyps in the gastrointestinal tract and hyperpigmented macules on the lips and oral mucosa (melanos ...

***

Adenoma An adenoma is a benign tumor of epithelial tissue with glandular origin, glandular characteristics, or both. Adenomas can grow from many glandular organs, including the adrenal glands, pituitary gland, thyroid, prostate, and others. Some adenom ...

s ***

Lipoma A lipoma is a benign tumor made of fat tissue. They are generally soft to the touch, movable, and painless. They usually occur just under the skin, but occasionally may be deeper. Most are less than in size. Common locations include upper back, ...

s ***

Hemangioma A hemangioma or haemangioma is a usually benign vascular tumor derived from blood vessel cell types. The most common form, seen in infants, is an infantile hemangioma, known colloquially as a "strawberry mark", most commonly presenting on the ski ...

s *** Ectopic gastric or pancreatic tissue ***

Meckel's diverticulum A Meckel's diverticulum, a true congenital diverticulum, is a slight bulge in the small intestine present at birth and a vestigial remnant of the omphalomesenteric duct (also called the vitelline duct or yolk stalk). It is the most common malformat ...

Protocol

At least four hours of no intake of solid foods, patient may have clear liquids.

Metoclopramide Metoclopramide is a medication used for stomach and esophageal problems. It is commonly used to treat and prevent nausea and vomiting, to help with emptying of the stomach in people with delayed stomach emptying, and to help with gastroesoph ...

(Reglan) will be administered to assist with emptying the stomach and increase movement through the small intestines. Large amounts of an oral contrast agent are given to the patient. Neutral contrast agents are preferred over positive contrast agents such as

barium Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element. Th ...

. The neutral agents are vitally important for the effective visualization of the lining of the small intestine. Use of positive contrast agents could make it difficult to see any inflammation in the lining. Neutral agents include water, EG electrolyte solution,

sugar alcohol Sugar alcohols (also called polyhydric alcohols, polyalcohols, alditols or glycitols) are organic compounds, typically derived from sugars, containing one hydroxyl group (–OH) attached to each carbon atom. They are white, water-soluble solids ...

s, and

methylcellulose Methyl cellulose (or methylcellulose) is a compound derived from cellulose. It is sold under a variety of trade names and is used as a thickener and emulsifier in various food and cosmetic products, and also as a bulk-forming laxative. Like cellu ...

. Patient are usually able to drink the large of amounts of these agents required for the study with major difficulty. This step is given at increments of 0, 20, 40, and 55 minutes after Reglan dose.

Glucagon Glucagon is a peptide hormone, produced by alpha cells of the pancreas. It raises concentration of glucose and fatty acids in the bloodstream, and is considered to be the main catabolic hormone of the body. It is also used as a Glucagon (medicati ...

is given to patient five minutes before they enter the CT scanner to counter act the previous medication and attempt to slow down bowel activity. Intravenous contrast is also given when the patient is on the scanner. The patient will then enter the scanner for the image to be captured.

Use in Crohn's Disease

CTE is preferred for the examination of

due to its increased spatial resolution and better ability to examine the wall of the small intestine than traditional CT studies of the abdomen and pelvis. Findings on CTE that indicate acitive inflammation in the small bowel, possibly caused by Crohn's disease, include: * Mural hyperenhancement * Mural stratification * Thickening of bowel wall * Mesenteric fat stranding * Enlarged vasa recta CTE is also used in examining if bowel inflammation improves after therapy and if the disease is progressing in a concerning way.

Contraindications and special considerations

* Pregnancy *

Bowel obstruction Bowel obstruction, also known as intestinal obstruction, is a mechanical or Ileus, functional obstruction of the Gastrointestinal tract#Lower gastrointestinal tract, intestines which prevents the normal movement of the products of digestion. Eith ...

Magnetic Resonance Enterography Magnetic resonance enterography is a magnetic resonance imaging technique used to evaluate bowel wall features of both upper and lower gastro-intestinal tract, although it is usually used for small bowel evaluation. It is a less invasive techniq ...

if that patient has a history of many CT scans previously * CT of abdomen and pelvis if unable to tolerate oral contrast

References

{{reflist Radiology X-ray computed tomography