A barium enema (or BE), also known as a lower GI (gastrointestinal) series, is a radiographic exam used to view the large intestine. There are two types of barium enemas: the single-contrast technique where just barium sulfate is injected into the rectum to outline the large intestine; and the double-contrast (or "air contrast") technique in which barium and air are injected into the rectum.
The purpose of a barium enema is to demonstrate the anatomy and morphology of the large intestine. The large intestine frames the abdomen and is divided into six sections. These include the rectum, sigmoid colon, descending colon, transverse colon, ascending colon, and cecum.
A barium enema may be performed for a variety of reasons, including abdominal pain or a change in bowel habits such as diarrhea or constipation, as well as a change in the caliber (size) of the stools. This exam is also requested when parasites, blood, mucus, or pus are found in the stools. Occult (hidden) blood found in the stools and anemia may be an indication of intestinal bleeding due to ulcers, inflammatory disease, or a cancerous lesion. Doctors may also order this exam as a screening tool for patients with a history of polyps (pre-cancerous growths extending outward from a mucous membrane) or a family history of colorectal cancer.
A barium enema may also be requested when the large intestine was not completely visualized during a
colonoscopy (examination of the large intestine with a fiber-optic tube) or when a sigmoidoscopy is done, which only partially visualizes the colon. Sometimes a barium enema may be used as a treatment for intussusception (telescoping of one section of the bowel into another causing obstruction). This is a rare disorder occuring most often in young children, but when it occurs immediate action must be taken.
A barium enema may also be done to evaluate the remaining colon on colostomy patients. The barium is injected into the stoma (external drainage opening in the abdominal wall) instead of the rectum. A barium enema may be done if obstruction, perforation, or fistula formation is suspected.
As with any radiographic procedure there is the risk of radiation. The x-ray technologist must always make sure there is no risk of pregnancy and that the least amount of films as possible are done. No lead shielding can be used since all the abdominal area must be visualized on the films.
All patients must be changed into a hospital gown. All clothing is removed, including shoes and socks, since some leakage of the barium mixture can occur. In some departments disposable slippers are supplied. The x-ray technologist may take one preliminary view of the abdomen to determine how well the patient's bowel has been cleansed. Any retained fecal material can create false filling defects and mucosal abnormalities on the films. A single-contrast enema would usually be done on patients with a poor bowel preparation. After the films are taken and the patient has evacuated as much of the barium as possible air may be introduced into the large intestine and further films taken. This method takes longer and gives more radiation to the patient.
The patient will be instructed to lie on the left side on the x-ray table, and the radiography technologist will insert a lubricated enema tip into the rectum. The enema tips contain a small balloon which may be inflated to help the patient retain the barium. The patient may remain on their left side or turned prone (face-down) depending on the procedure and routine of the radiologist.
For a single-contrast barium enema, the barium sulphate solution is a thinner consistency but a larger amount is needed to completely fill the large intestine. High kilovoltage (100-125kvp) is used to get a good penetration of the barium filled colon, and it is important to take the films as quickly as possible since the patients are very uncomfortable when the bowel is completely distended. Routine films for a single contrast study include a supine and prone abdomen film as well as both obliques to see the hepatic and spenic flexures of the large bowel. The patient will completely evacuate the bowel and one more film, the post-evacuation film (PE) usually done AP (anteroposterior, or frontoack) supine, will be taken.
In a double-contrast barium enema, a fine coating of thick barium is needed to outline the mucosal lining of the bowel. The patient will be placed prone so that gravity can assist the air in distributing the liquid around the large bowel. The patient is asked to turn over 360 degrees a few times during the exam to aid in the coating of the bowel. The patient is then placed upright, and more air is injected into the bowel so gravity again can assist in visualizing the large intestine. Patients may develop spasms of the bowel during this exam, so the radiologist may give the patient a glucagon injection to relax the large bowel. This injection should not be given to patients with a history of glaucoma and can cause temporary double-vision in these patients.
The radiologist will take spot-films under fluoroscopy of each segment of the bowel but most of the films will be made following the procedure by the x-ray technologist. Since less barium is used along with some air, less kilovoltage (90-100kvp) is needed to achieve a high contrast x-ray of the large intestine. The usual AP and PA (posteroanterior) abdomen films will be done as well as the two oblique views of the abdomen. An upright film may be done as well depending on the routine of the radiologist. The most important films for the double-contrast exam are the two lateral decubitus films. The patient is placed on a large cushion or sponge and turned completely onto one side. A stationary grid is placed next to the patient and the x-ray tube is turned 90 degees. This film allows the air to rise to the upper surface of the abdomen so that the air along with the thin coating of barium creates a detailed visualization of the intestinal lining. This is extremely important when looking for small polyps, cancers, and ulcerations of the bowel. Films of both sides are always taken.
In order to conduct the most accurate barium enema test, the patient must follow a prescribed diet and bowel preparation prior to the test. This includes a diet of tea, coffee (black), clear soups, and gelatin 24-48 hours before the barium enema. Laxatives and cathartics such as magnesium citrate (X-Prep) or Dulcolax tablets may also be required as part of the bowel preparation. Each radiology department has their own specific requirements. A rectal suppository or cleansing enema may also be necessary on the morning before the exam. Patients must drink as much fluids as possible to prevent dehydration. Patients with heart disease, diabetes, or kidney disorders should consult their physician for an alternate bowel preparation. Children are usually placed on a clear liquid diet on the day before their examination.
A barium enema may be done in a hospital or a certified x-ray clinic and will take 30 minutes to one hour depending on what type of exam has been ordered and the physical ability of the patient.
Patients should follow several steps immediately after undergoing a barium enema, including:
- Drinking plenty of fluids to help counteract the dehydrating effects of the bowel preparation.
- Taking time to rest. A barium enema and the bowel preparation taken before it can be exhausting.
- A cleansing enema or laxative may be given to eliminate any remaining barium. White stools containing barium are normal for two or three days following a barium enema.
While a barium enema is considered a safe screening test used on a routine basis, it can cause complications in certain patients. The following contraindications should be kept in mind before a barium enema is performed:
- Those who have a rapid heart rate, severe ulcerative colitis, toxic megacolon, or a presumed perforation in the intestine should not undergo a barium enema.
- The test can be cautiously performed if the patient has a blocked intestine. Gastrograffin, an iodine-based contrast, will be used instead of the barium in case emergency surgery is needed following the barium enema.
A normal result indicates no structural or filling defects of the large intestine. Radiologists look for any enlargement or narrowing of the large bowel as well as variations in the mucosal lining. The walls of the intestine should collapse normally after the post-evacuation film, and the bowel should have normal haustral markings (undulations of the colon wall).
Abnormal results may include colorectal polyps, diverticulosis (multiple abnormal sacs bulging through the intestinal wall), ulcerative colitis, abscesses, or tumors visualized on the walls or adjacent to the large intestine. Further evaluation such as a biopsy or CT scan may be necessary to determine the extent of any positive findings.
Health care team roles
It is the resposibility of the radiography technologist to prepare the barium, insert the enema tip, and take the overhead films after the radiologist has filled the entire colon with either the barium or a combination of barium and air. In some departments an interventional radiology technologist will perform the complete exam. He or she will have had additional education and training by the radiologists to complete this duty.
The x-ray technologist must work closely with the nurses to make sure all hospital patients follow the bowel preparation. Since the preparation is physically exhausting for the patient, care is taken to complete the exam as soon as possible so the patient may resume a normal diet.
Since a good preparation is the most important step in a barium enema, all patients should receive detailed information on the reasons and requirements for the cleansing treatment. The x-ray technologist must explain the procedure in detail before starting the exam. The patient must be informed that the barium enema can sometimes cause cramps and that the urge to have a
bowel movement is completely normal. Some leakage of the barium may occur and the patient should not feel embarrassed if this happens because it occurs fairly often, especially in elderly patients. Care should be taken when inserting the enema tip because the rectum is already irritated, due to the multiple bowel movements during the preparation. The x-ray technologist must take note of any history of glaucoma in case an injection of glucagon is needed. Patients should be completely covered at all times and care taken when placing the patient in the upright position since many patients are weak after undergoing the bowel preparation.
The x-ray technologist should also explain to the patient the need to drink plenty of fluids after the barium enema and that white stools following a barium enema are normal.
All radiography technologists must be certified, having completed a two to four year program depending on where the course was completed. All x-ray technologists must be registered with the A.S.R.T. and earn continuing education credits to remain registered.
Barium sulfate barium compound used during a barium enema to block the passage of x rays during the exam, allowing visualization of the intestinal lining.
Colonoscopyn examination of the large colon performed with a colonoscope.
Diverticula (plural of diverticulum) sac or pouch in the colon walls which is usually asymptomatic (without symptoms) but may cause difficulty if it becomes inflamed.
Diverticulitis condition of the diverticula of the intestinal tract, especially in the colon, where inflammation may cause and pain.
Diverticulosis condition of the colon characterized by the presence of diverticula.
Glaucoma disease of the eye characterized by increased ocular pressure resulting in damage to the retina and optic nerve if not treated.
Sigmoidoscopy visual examination of the rectum and sigmoid colon using a fiberoptic sigmoidoscope.
Ulcerative colitisn ulceration or erosion of the mucosa of the colon.
Eisenberg, Ronald. Clinical Imaging: An Atlas of Differential Diagnosis, 3rd Ed. Philadelphia: Lippincott, Williams & Wilkins, 1996.
Segen, Joseph C., and Joseph Stauffer. "Barium Enema (lower GI series)." In The Patient's Guide To Medical Tests: Everything You Need To Know About The Tests Your Doctor Prescribes. New York, NY: Facts On File, Inc., 1998, pp. 44-45.
Friedenberg, Richard M.D. "The supertechnologist." Radiology Review (June 2000): 630-633.
American Cancer Society. 1599 Clifton Road NE, Atlanta, GA 30329-4251. (800) ACS-2345. <<a href="http://www.cancer.org/">http://www.cancer.org/>.
Health Discovery. <<a href="http://www.healthdiscovery.com/diseasesandconditions">http://www.healthdiscovery.com/diseasesandconditions>
Lorraine K. Ehresman
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