What is Virtual Colonoscopy: Overview, Benefits, and Expected Results

Definition and Overview

Virtual colonoscopy or CT colonography is an imaging test of the colon that generates multiple cross-sectional photos using CT scan. It can be helpful in providing a more detailed image of the colon including the rectum, especially if the presence of polyps, which can be pre-cancerous, is suspected.

This type of test is different from standard colonoscopy, which uses a long flexible tube inserted into the rectum all the way to the colon to check for polyps.

Who Should Undergo and Expected Results

Virtual colonoscopy may be carried out if the patient develops gastrointestinal-related illnesses or symptoms like:

• Bleeding during bowel movement
• Changes in bowel movement
• Abdominal pain or cramps
• Unexplained weight loss
• Frequent passing of gas
• Bloating
• Feeling of satiation despite eating small meals

It may also be suggested if the person has gone through a fecal occult blood test (FOBT), a routine exam that can identify the presence of blood in the collected stool sample. The CT scan is therefore needed for further diagnosis or investigation.

People who are at least 50 years old are recommended to undergo colon cancer screening test, of which the interval varies on the actual test performed. Those whose condition is familial may have to go through the testing much earlier and more often than the general population.

The actual scanning takes only a few minutes, but the entire process may last for at least an hour. The scan must be able to determine the condition of the colon including the presence of polyps.

How Does the Procedure Work?

A gastroenterologist recommends the procedure to the patient based on the results of previous medical tests and symptoms. The patient schedules the scan as certain preparations have to be carried out. These include the intake of a special type of fluid to cleanse the colon. There are also diet restrictions. A day before the exam, the patient can only consume liquids.

During the actual exam, a technologist will assist the patient as he is positioned on a flat table. Gas is introduced through the rectum using an electric pump or a flexible tube. The air will ensure that the colon is distended. Straps are also attached to the body to keep the person from moving during the scan.

The table then goes through the scanner. When the technician is ready to take images, the patient may have to hold his breath for at least 15 seconds. Through a speaker and a microphone, the technician communicates from the other room and instructs the patient on what else to do.

After the exam, the radiologist analyzes the images gathered. If there’s a polyp, the patient proceeds to regular colonoscopy to remove it.

Possible Risks and Complications

Virtual colonoscopy is less sensitive to polyps measuring less than 7mm. It is possible to miss out certain precancerous polyps, especially if the radiologist doesn’t have enough experience in performing the procedure.

Going through CT colonography doesn’t immediately eliminate the need for regular colonoscopy (which is more invasive), particularly since it’s the only way to remove the polyps so they can be taken to the lab for biopsy.

References:

• Cash BD, Rockey DC, Brill JV. AGA standards for gastroenterologists for performing and interpreting diagnostic computed tomography colonography: 2011 update. Gastroenterology. 2011;141:2240-2266. PMID 22098711. Available at: www.ncbi.nlm.nih.gov/pubmed/22098711.

• Kim DH, Pickhardt PJ. Computed tomography colonography. In: Gore RM, Levine MS, eds. Textbook of Gastrointestinal Radiology. 4th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 53.

• National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines): Colorectal cancer screening. Version 1.2014. Available at: www.nccn.org/professionals/physiciangls/pdf/colorectalscreening.pdf. Accessed February 12, 2015.

• U.S. Preventive Services Task Force. Screening for colorectal cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2008;149:627-637. PMID 18838716. Available at: www.ncbi.nlm.nih.gov/pubmed/18838716.

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**What is Virtual Colonoscopy: Overview, Benefits, and Expected Results**



**Overview**



Virtual colonoscopy (also known as CT colonography) is ‌a non-invasive medical imaging procedure ‌that uses advanced computed tomography⁤ (CT) scanning technology to provide detailed images of the colon ‌and rectum. Unlike traditional colonoscopy, virtual colonoscopy does not require insertion of ​an endoscope‍ into the ‌colon, making it a more comfortable and convenient option for patients.



**Procedure**



To prepare⁤ for a virtual colonoscopy, patients undergo⁤ a bowel cleansing regimen to remove all stool from the colon. During the ⁣procedure, a ⁢contrast agent is ‍administered through the rectum to help visualize the colon during scanning. Patients are‍ then positioned on a CT scanner, where a series of axial ⁤and coronal images are acquired. Advanced computer software processes the images to generate three-dimensional reconstructions of the colon.



**Benefits**



* **Non-invasive:** Unlike traditional⁣ colonoscopy, virtual colonoscopy does not require ‌insertion of⁢ an endoscope, significantly reducing patient discomfort and the risk ​of⁢ complications.

* **Comfortable:** Patients experience‌ only a slight abdominal sensation when the contrast agent is​ administered. General anesthesia⁣ is not required.

* **Shorter recovery⁣ time:** Patients can resume their‌ normal​ activities immediately after the procedure.

* ⁤**Cost-effective:** Virtual colonoscopy is ‍generally less expensive than traditional colonoscopy.

* **Suitable for certain patients:** Virtual colonoscopy is particularly beneficial for patients who are unable to tolerate traditional colonoscopy due to ⁣health conditions, pain, or anxiety.

* **Detection of conditions:** Virtual colonoscopy can detect a range of conditions, including polyps, tumors, diverticulitis, and‌ inflammatory bowel disease.



**Expected Results**



After the virtual colonoscopy, the ‍images are interpreted by a radiologist. The radiologist will provide a ‌written report that includes:



* Findings: Any polyps or abnormalities identified​ in⁤ the colon.

* Interpretation: The size, location, and appearance of any abnormalities.

* Recommendations:​ Follow-up tests or treatments that​ may be necessary if abnormalities are‌ found.



**Follow-Up**



If polyps or other abnormalities are detected during a virtual colonoscopy, the patient may be ‌referred for further evaluation through either a traditional​ colonoscopy or endoscopic ultrasound. The recommended⁣ follow-up plan will vary depending on‍ the size, location, and appearance of the abnormalities.



**Conclusion**



Virtual colonoscopy is a valuable medical imaging tool that offers a ‌non-invasive and comfortable⁣ method for ‌evaluating the colon ​and rectum. ⁣By using ⁢advanced CT scanning‌ technology, virtual colonoscopy provides detailed images that can detect a range⁢ of conditions with high accuracy. It serves as an effective screening and diagnostic tool for colorectal cancer and other‌ colon-related diseases.