WordNet

an injection of a liquid through the anus to stimulate evacuation; sometimes used for diagnostic purposes (同)clyster
a soft silvery metallic element of the alkali earth group; found in barite (同)Ba, atomic number 56

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かん腸;〈C〉かん腸剤(器)
バリウム(金属元素・化学記号はBa)

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/02/18 13:41:52」(JST)

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A lower gastrointestinal series, also called a barium enema, is a medical procedure used to examine and diagnose problems with the human colon (large intestine). X-ray pictures are taken while barium sulfate fills the colon via the rectum.

Procedure

This test may be done in a hospital or clinic. The patient lies on the X-ray table and a preliminary X-ray is taken. The patient is then asked to lie on the side while a well lubricated enema tube is inserted into the rectum. As the enema enters the body, the patient might have the sensation that they have to have a bowel movement. The barium sulfate, a radiodense (shows as white on X-ray) contrast medium, is then allowed to flow into the colon. A large balloon at the tip of the enema tube may be inflated to help keep the barium sulfate inside. The flow of the barium sulfate is monitored by the health care provider on an X-ray fluoroscope screen (like a TV monitor). Air may be puffed into the colon to distend it and provide better images (often called a "double-contrast" exam). If air is used, the enema tube will be reinserted if it had been removed and a small amount of air will be introduced into the colon, and more X-ray pictures are taken.

The patient is usually asked to move to different positions and the table is slightly tipped to get different views.

If there is a suspected bowel perforation, a water-soluble contrast agent is used instead of barium. The procedure is otherwise very similar, although the images will be of poorer quality. If a perforation exists, the contrast will leak from the bowel to the peritoneal cavity; water-soluble material is less obscuring compared to barium should an abdominal incision to remove the contrast be necessary.

Preparation

Thorough cleaning of the large intestine is necessary for accurate pictures. Test preparations include a clear liquid diet or nothing at all (nihil per os or NPO) after midnight, drinking a bottle of magnesium citrate (a laxative), and warm water enemas to clear out any stool particles.

Purpose

A barium enema clearly displays a colonic herniation.

Barium enemas are most commonly used to check bowel health; they can help diagnose and evaluate the extent of inflammatory bowel diseases such as ulcerative colitis and Crohn's disease. Polyps can be seen, though not removed during the exam like with a colonoscopy— they may be cancerous. Other problems such as diverticulosis (small pouches formed on the colon wall that can become inflamed) and intussusception can be found (and in certain cases the test itself can treat intussusception). An acute appendicitis or twisted loop of the bowel may also be seen. If the picture is normal a functional cause such as irritable bowel syndrome (IBS) may be considered.

In a healthy colon, barium should fill the colon uniformly and show normal bowel contour, patency (should be freely open), and position.

Additional conditions under which the test may be performed:

CMV gastroenteritis/colitis
Hirschsprung's disease
intestinal obstruction
intussusception (children)

Risks

X-rays are monitored and regulated to provide the minimum amount of radiation exposure needed to produce the image. Most experts feel that the risk is low compared with the benefits. Pregnant women and children are more sensitive to the risks of ionizing radiation.

A more serious risk is a bowel perforation.

Special considerations

CT scans and ultrasounds are now the tests of choice for the initial evaluation of abdominal masses, and colonoscopies are becoming the standard for routine colon screening for those over age 50 or with a familial history of polyps or colon cancer, although it is not uncommon for a barium enema to be done after a colonoscopy for further evaluation.

Bibliography

External links

Duplicated Colon on Barium Enema - MedPix Medical Image Database
RadiologyInfo - The radiology information resource for patients: Barium Enema
NIH page on barium enemas

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English Journal

Levels and variation in overuse of fecal occult blood testing in the veterans health administration.

Partin MR, Powell AA, Bangerter A, Halek K, Burgess JF Jr, Fisher DA, Nelson DB.SourceCenter for Chronic Disease Outcomes Research, Minneapolis Veterans Affairs Medical Center, One Veterans Drive (2E-152), Minneapolis, MN, 55417, USA, melissa.partin@va.gov.
Journal of general internal medicine.J Gen Intern Med.2012 Dec;27(12):1618-25. doi: 10.1007/s11606-012-2163-9. Epub 2012 Jul 19.
BACKGROUND: Policy-makers have called for efforts to reduce overuse of cancer screening tests, including colorectal cancer screening (CRCS). Overuse of CRCS tests other than colonoscopy has not been well documented.OBJECTIVE: To estimate levels and correlates of fecal occult blood test (FOBT) overus
PMID 22810358

A single FIT (≥ 50 ng Hb/mL) detected 38% of screen-detected advanced colorectal neoplasia.

Logan RF.AbstractQUESTION Does the fecal immunochemical test (FIT) accurately detect advanced adenoma and advanced neoplasia in persons invited to primary colonoscopy screening? METHODS DESIGN Blinded comparison of FIT with screening colonoscopy. SETTING Amsterdam and Rotterdam, The Netherlands. PARTICIPANTS 1256 asymptomatic persons (median age 60 y, 51% men) who were scheduled for colonoscopy in a population-based screening trial also completed a FIT before colonoscopy. Exclusion criteria were full colonic examination (complete colonoscopy, computed tomography colonography, and/or double-contrast barium enema) in the past 5 years, planned surveillance colonoscopy (personal history of colorectal cancer, colonic adenomas, or inflammatory bowel disease), or an end-stage disease with life expectancy < 5 years. DESCRIPTION OF TEST 1 sample FIT (OC-Sensor, Eiken Chemical, Tokyo, Japan). Patients swept the FIT probe through a stool sample ≤ 48 hours before colonoscopy and before beginning bowel preparation. Samples were stored at -20°C (-4°F) and analyzed within 6 weeks. Cutpoints for hemoglobin (Hb) levels (Hb/mL of test buffer) were 50 ng/mL (10 µg Hb/g feces), 75 ng/mL (15 µg Hb/g feces), and 100 ng/mL (20 µg Hb/g feces). DIAGNOSTIC STANDARD Screening colonoscopy. OUTCOMES Sensitivity, specificity, and likelihood ratios for detecting ≥ 1 advanced adenoma (adenoma ≥ 10 mm, ≥ 25% villous, or high-grade dysplasia) and advanced neoplasia (advanced adenoma and/or colorectal carcinoma). MAIN RESULTS 9% of participants had ≥ 1 advanced adenoma, 0.6% had colorectal carcinoma, and 9.5% had advanced neoplasia. Diagnostic test characteristics of FIT are shown in the Table. CONCLUSION In participants who had screening colonoscopy, a single fecal immunochemical test (cutpoint ≥ 50 ng/mL) had 35% sensitivity and 93% specificity for detecting advanced adenoma, and 38% sensitivity and 93% specificity for detecting advanced neoplasia.Diagnostic test characteristics of fecal immunochemical test (FIT) in persons invited to primary screening colonoscopy for colorectal cancer*OutcomesFIT cutpointSensitivity (95% CI)Specificity (CI)LR+LR-NNSAdvanced adenoma≥ 50 ng/mL35% (27 to 45)93% (91 to 94)5.00.7031≥ 75 ng/mL31% (23 to 40)95% (94 to 96)6.70.7236≥ 100 ng/mL29% (21 to 39)97% (95 to 98)8.80.7338Advanced neoplasia≥ 50 ng/mL38% (29 to 47)93% (92 to 95)5.70.6728≥ 75 ng/mL33% (25 to 42)96% (94 to 97)7.60.7032≥ 100 ng/mL31% (23 to 40)97% (96 to 98)10.40.7134*NNS = number needed to screen; diagnostic terms defined in Glossary.
Annals of internal medicine.Ann Intern Med.2012 Nov 20;157(10):JC5-10. doi: 10.7326/0003-4819-157-10-201211200-02010.
QUESTION Does the fecal immunochemical test (FIT) accurately detect advanced adenoma and advanced neoplasia in persons invited to primary colonoscopy screening METHODS DESIGN Blinded comparison of FIT with screening colonoscopy. SETTING Amsterdam and Rotterdam, The Netherlands. PARTICIPANTS 1256 a
PMID 23165686