×

Please Remove Adblock
Adverts are the main source of Revenue for DoveMed. Please remove adblock to help us create the best medical content found on the Internet.

Computed Tomography (CT) - Colonography

Last updated Nov. 30, 2018

Approved by: Krish Tangella MD, MBA, FCAP

Raziel

A Computed Tomography (CT) scan is a noninvasive test that can be used to screen for cancerous polyps in the colon (large intestine) and rectum, or if any associated symptoms of colon or rectal cancer (colorectal cancer) are observed.


Background Information:

What are the other Names for the Procedure?

  • CT Scan of the Colon and Rectum
  • Virtual Colonoscopy
  • X-ray Computed Tomography - Colon and Rectum

What is Computed Tomography (CT) scan of the Colon and Rectum radiology procedure? (General Explanation)

  • CT (Computed Tomography) scanning, also referred to as a CAT scan, is a noninvasive test used to diagnose and treat medical conditions, by combining a special X-ray machine with computers, to produce images of the body insides
  • CT scanning provides more details of soft tissues, blood vessels, and internal organs, than a regular X-ray exam
  • A ‘Computed Tomography (CT) - Colonography’ scan can be used to screen for cancerous polyps in the colon (large intestine) and rectum, or if any associated symptoms of colon or rectal cancer (colorectal cancer) are observed

What part of the Body does the Procedure involve?

A Virtual Colonoscopy involves the colon (large intestine), small intestine, and the rectum.

Why is the Computed Tomography (CT) scan of the Colon and Rectum radiology procedure Performed?

A Virtual Colonoscopy is performed for the following reasons:

  • To screen for polyps or cancer in the large intestine (polyps arise in the inner lining of the intestine and may turn into cancers). The goal is to find polyps at earlier stages, so they may be removed, before they develop into cancers
  • Colon screening for men and women over the age of 50 years, performed once every 10 years
  • Individuals with a family history of colorectal (colon) cancer are recommended for screening, beginning at the age of 40 years
  • If symptoms of colorectal cancers are observed, such as blood in stool, abdominal pain or discomfort, change in bowel habits, weight-loss, or bloating

What is the Equipment used? (Description of Equipment)

The CT equipment for a Virtual Colonoscopy consists of:

  • A CT scanner that appears like a big box with a hole inside
  • The examination table on which the patient lies down; the table slides into the hole during the procedure
  • X-ray tube and electronic X-ray detectors that rotates around the patient
  • Images are taken from a computer

A transducer (part of the scanner) is used to send high frequency sound waves in the body and the computer creates the images, based on the echoes of that sound returning from the patient’s body.

What are the Recent Advances in the Procedure?

There have been no recent advances to replace the CT scan procedure.

What is the Cost of performing the Computed Tomography (CT) scan of the Colon and Rectum radiology procedure?

The cost of a Virtual Colonoscopy depends on a variety of factors, such as the type of your health insurance, annual deductibles, co-pay requirements, out-of-network and in-network of your healthcare providers and healthcare facilities.

In many cases, an estimate may be provided before the procedure. The final amount depends upon the findings during the surgery/procedure and post-operative care that is necessary.

When do you need a Second Opinion, prior to the Procedure?

  • It is normal for a patient to feel uncomfortable and confused with a sudden inflow of information regarding the Virtual Colonoscopy procedure and what needs to be done
  • If the patient needs further reassurance or a second opinion, a physician will almost always assist in recommending another physician
  • Also, if the procedure involves multiple steps or has many alternatives, the patient may take a second opinion to understand and choose the best one. They can also choose to approach another physician independently

What are some Helpful Resources?

http://www.radiologyinfo.org/en/info.cfm?pg=ct_colo (accessed on June 7, 2014)

Prior to Computed Tomography (CT) scan of the Colon and Rectum radiology procedure:

How does the Computed Tomography (CT) scan of the Colon and Rectum radiology procedure work?

  • A CT scan is very similar to taking an X-ray. In an X-ray, radiation passes through the body and an image is recorded on photographic film. The bones appear white, air appears black, and soft tissues appear as gray patches
  • In the CT scan, electronic X-ray detectors and X-ray beams rotate (around the patient) and measure the amount of radiation absorbed
  • The X-ray beam in a CT scan follows a spiral path, as the examination table is moving through the scanner
  • A two-dimensional, cross sectional image of the body is created by a computer program, by utilizing all the data generated by the scanner. The CT scan produces a very detailed multidimensional view of the body’s interior regions
  • The CT scan produces images of the abdomen and intestinal region, in a way as can be compared to looking at a loaf of bread, by cutting the loaf into thin slices

How is the Computed Tomography (CT) scan of the Colon and Rectum radiology procedure Performed?

  • For a CT - Colon and Rectal scan, the patient is asked to lay flat on their back, side, or on their stomach, during the examination
  • As any motion may affect the quality of examination, the patients are asked to stay still on the table; children may be given a sedation, to keep them still
  • A small tube is inserted into the rectum of the patients, to allow pumping of air, in order to keep the colon distended and avoid obscuring of polyps from any folds of the colon
  • The CT table moves into the scanner and the patients are asked to hold their breath for about 15 seconds

Where is the Procedure Performed?

A Virtual Colonoscopy is performed as an outpatient procedure, at a hospital.

Who Performs the Procedure?

A Virtual Colonoscopy is usually performed by a radiology technologist.

How long will the Procedure take?

The Virtual Colonoscopy scan will take about 30-60 minutes.

Who interprets the Result?

  • A radiologist interprets the results of the scan
  • Some hospitals may perform a colonoscopy and polyp removal procedure, right after a CT Colonography, if necessary
  • Follow-up examination may be needed, if anything suspicious is detected during the exam, or to monitor the abnormality over time
  • A follow-up is also availed in order to check effectiveness of the treatment administered

What Preparations are needed, prior to the Procedure?

The following preparations may be needed prior to a Computed Tomography (CT) - Colonography scan:

  • The physician may evaluate the individual’s medical history to gain a comprehensive knowledge of the overall health status of the patient, including information related to the medications that are being currently taken
  • Do inform the medical professional if you have a history of any medical conditions, such as a heart disease, asthma, diabetes, or kidney disease
  • Do inform the medical professional about any allergies, especially related to barium or iodinated contrast material, which may be used in the procedure
  • It is advisable to wear comfortable and loose clothes. Avoid wearing any metal objects or jewelry, as it may interfere with the x-ray
  • It is highly recommended to inform your healthcare professional, if you are pregnant or breastfeeding
  • The patient must avoid eating or drinking at least 8 hours prior to the procedure, depending on when the procedure is arranged
  • The individual may have to undergo a bowel cleansing regimen:
    • It is employed before a CT Colonography to clean the colon, before the procedure, so that the polyps are clearly seen
    • The individuals are asked to be on clear liquids, a day before the exam
    • They are asked to take pills or cathartic liquid, as it helps to distinguish stool from polyps

What is the Consent Process before the Procedure?

A physician will request your consent for a Colon and Rectal CT scan procedure using an Informed Consent Form.

Consent for the Procedure: A “consent” is your approval to undergo a procedure. A consent form is signed after the risks and benefits of the procedure, and alternative treatment options, are discussed. This process is called informed consent.

You must sign the forms only after you are totally satisfied with the answers to your questions. In case of minors and individuals unable to personally give their consent, the individual’s legal guardian or next of kin, shall give their consent for the procedure.

What are the Benefits versus Risks, for this Procedure?

Following are the benefits of the CT Colonography procedure:

  • There is much lower risk of perforating the colon during a Virtual Colonoscopy, than through a conventional colonoscopy
  • It provides very detailed and clear images, than from a regular colonoscopy. No recovery period is necessary and it is also less expensive. If there are polyps, then these are visualized with a CT scan, as clearly as with conventional colonoscopy. It is noninvasive, accurate, fast, easy, and painless
  • Most of the patients undergoing CT do not need to go through a colonoscopy, as most of them do not have polyps
  • This technique is a great alternative for patients on blood thinners, breathing problems, or having complications associated with a regular colonoscopy
  • In cases of large tumors or obstruction of the large intestine, where colonoscopy cannot be used, a CT scan can be very useful
  • Elderly adult individuals and patients tolerate this procedure much better
  • The radiation does not remain in the patient’s body and there are no side effects.

Following are the risks of the CT Colonography procedure:

  • Over-exposure to radiation in a CT scan procedure may cause cancer. But, generally the chances of developing cancer is very remote
  • There is a slight risk that the contrast material, which is used to distend the colon, may perforate the bowel

What are the Limitations of the Computed Tomography (CT) scan of the Colon and Rectum radiology procedure?

  • The Computed Tomography (CT) - Colonography procedure is not recommended for patients with ulcerative colitis, Crohn’s disease, diverticulitis, and inflammatory bowel disease, as these patients have an increased risk of colon perforation
  • The CT scan is only a diagnostic procedure; if a polyp is detected, patients still need to go through a regular colonoscopy, to have it removed
  • In some cases, obese or large patients may have a difficulty in bodily fitting into the CT scanner
  • Sometimes, certain insurance policies may not cover the cost of this procedure

What are some Questions for your Physician?

Some of the basic questions that you might ask your healthcare provider or physician are as follows:

  • What is a Computed Tomography - Colonography scan procedure?
  • Why is this procedure necessary? How will it help?
  • How soon should I get it done? Is it an emergency?
  • Who are the medical personnel involved in this procedure?
  • Where is the procedure performed?
  • What are the risks while performing the procedure?
  • What are the complications that might take place, during recovery?
  • What are the possible side effects from the procedure? How can I minimize these side effects?
  • How long will it take to recover? When can I resume normal work?
  • How many such procedures have you (the physician) performed?
  • Are there any lifestyle restrictions or modifications required, after the procedure is performed?
  • Are there any follow-up tests, periodic visits to the healthcare facility required, after the procedure?
  • Is there any medication that needs to be taken for life, after the procedure?
  • What are the costs involved?

During the Computed Tomography (CT) scan of the Colon and Rectum radiology procedure:

What is to be expected during the Computed Tomography (CT) scan of the Colon and Rectum radiology procedure?

During a Computed Tomography - Colonography scan procedure, the patient may experience the following:

  • There is a chance for the patient to feel full, when the colon is distended with air
  • There is no pain involved with this procedure
  • There might be some noise of the device, as involved with any regular machine function
  • The individual may experience some anxiety, due to the noise of the machine, or from staying still for a long time, but no scan associated pain may be felt

What kind of Anesthesia is given, during the Procedure?

No anesthesia is administered during the Computed Tomography - Colonography procedure.

How much Blood will you lose, during the Procedure?

There is no blood loss during the Computed Tomography - Colonography procedure.

What are the possible Risks and Complications during the Computed Tomography (CT) scan of the Colon and Rectum radiology procedure?

  • Over-exposure to radiation in a CT Scan of the Colon and Rectum procedure may cause cancer; however, such a risk is very low
  • The CT scan procedure is not recommended for pregnant women
  • Mothers are advised to breastfeed their children, only 24 hours after the contrast material for CT scanning is injected
  • There is a rare chance of developing an allergic reaction, due to the contrast material containing iodine used in the CT scan
  • CT scanning is recommended for children, only if it is absolutely necessary, as children are very radiation-sensitive

What Post-Operative Care is needed at the Healthcare Facility after the Computed Tomography (CT) scan of the Colon and Rectum?

There is no post-operative care necessary after a Colon and Rectal CT scan, at the healthcare facility.

After the Computed Tomography (CT) scan of the Colon and Rectum radiology procedure:

What is to be expected after the Computed Tomography (CT) scan of the Colon and Rectum radiology procedure?

Generally, no complications or side effects are observed after the Computed Tomography - Colonography scan procedure.

When do you need to call your Physician?

If the patient is experiencing an allergic reaction from the contrast reaction; then, do contact the physician.

What Post-Operative Care is needed at Home after the Computed Tomography (CT) scan of the Colon and Rectum radiology procedure?

There is no post-operative care necessary after a Computed Tomography - Colonography scan, at home.

How long does it normally take to fully recover, from the Procedure?

The patient needs no recovery time after the Computed Tomography - Colonography scan.

Additional Information:

What happens to tissue (if any), taken out during the Procedure?

No tissue is extracted from the patient during a Computed Tomography - Colonography procedure.

When should you expect results from the pathologist regarding tissue taken out, during the Procedure?

Since no tissue is removed during the procedure, a pathologist does not get involved in the care of the patient.

Who will you receive a Bill from, after the Procedure?

It is important to note that the number of bills that the patient may receive depends on the arrangement the healthcare facility has with the physician and other healthcare providers.

Sometimes, the patient may get a single bill that includes the healthcare facility and the consultant physician charges. Sometimes, the patient might get multiple bills depending on the healthcare provider involved. For instance, the patient may get a bill from:

  • The hospital, where the procedure is performed
  • Radiologist or neurologist, performing the procedure
  • Healthcare providers, physicians, who are involved in the process

The patient is advised to inquire and confirm the type of billing, before the Computed Tomography - Colonography procedure is performed.

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: June 10, 2014
Last updated: Nov. 30, 2018