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Virtual Colonoscopy - Frequently Asked Questions

The Princeton Longevity Center for
3-D Virtual Colonoscopy

1. Who should have a  Virtual Colonoscopy?

2. What type of Prep is required?

3. What should I expect during a Virtual Colonoscopy?

4. How much X-Ray exposure is involved?

5. Why do a Virtual Colonoscopy if I may need a regular Colonoscopy if an abnormality is found?

7. Who will read my Virtual Colonoscopy?

8. What about those ads I hear for other centers offering discount prices for Virtual Colonoscopy?

9. Will my insurance company reimburse Virtual Colonoscopy?

10. How do make an appointment for a Virtual Colonoscopy?

1.Who should have a  Virtual Colonoscopy?

 The American Cancer Society recommends screening for colorectal cancer beginning at age 50.  If you have a family history of colon cancer or polyps, or if you are African-American, screening should begin at age 40.
Virtual Colonoscopy is also particularly useful for patients in the following categories:

A.   Patients on Coumadin therapy.  There is no need to discontinue anticoagulation for a Virtual Colonoscopy.

B.   Patients who require antibiotic prophylaxis for invasive procedures.  Virtual Colonoscopy does NOT require antibiotic prophylaxis

C.   Incomplete/Failed Optical Colonoscopy or Occlusive Disease of the colon.  Published studies have reported that Optical Colonoscopy can not be completed  in 10-20% of cases.  Virtual Colonoscopy will frequently be able to image the remainder of the colon when spasm, poor prep or obstructive tumors prevent passage of a colonoscope throughout the length of the colon.

D.   Patients too frail to tolerate anesthesia or invasive procedures.  Virtual Colonoscopy does not require any anesthesia.  Therefore, it is ideal for patients who are unable or unwilling to tolerate an invasive procedure or are concerned about effects of anesthesia.

E.   Patients who are resistant to Optical Colonoscopy.   Virtual Colonoscopy offers a comfortable alternative that is non-invasive, does not require sedation and does not require the patient to miss a day of work.

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2.      What kind of prep is required?

Patients are advised to follow a liquid diet for 24 hours prior to their scans.  A well-cleansed colon is required to achieve high sensitivity and specificity.   The night prior to the scan, the patient you take 3 oz of Fleet Phosphasoda (divided into 3 doses).  Patients generally report little or no difficulty with the prep.  For those patients who are unable or unwilling to follow a liquid diet, a low-residue, tasty and highly nutritious meal package is available from EZEM.

In the near future it may be possible to perform Virtual Colonoscopy without a laxative prep.  The use of barium tagging of each meal for 24-48 hours prior to the scan allows for the digital subtraction of the colon contents.  However, the sensitivity and specificity of Virtual Colonoscopy using this methodology has not yet been as well established.

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3.      What should I expect during a Virtual Colonoscopy?

The Virtual Colonoscopy is a quick and easy procedure.  A very small rubber catheter tip is inserted into the rectum and the colon is gradually insufflated.  The Princeton Longevity Center uses CO2 insufflated under controlled pressure.  Inflation with CO2 causes less cramping than room air.  In addition, it is quickly absorbed from the colon after the procedure so there is no concern about having to expel air from the colon during the hours following the procedure.  The ability to carefully control the insufflation pressure also enhances patient comfort.  Because the CO2 is quickly absorbed, you can expect to feel entirely back to normal by the time you leave the scanner room.

Adequate insufflation is generally achieved in less than 5 minutes.  Then two scans are done, one laying on your back and one laying on your stomach.  Each scan is a single breath-hold scan that takes approximately 10 seconds.  The change in position allows for movement of any retained stool or fluid, improving the sensitivity of the procedure.    .

Before your scan, our we will review your medical history and fully explain the procedure.  Following the test, you are welcome to spend a few minutes in our lounge area where a breakfast or light snack is provided.  The final report from our radiologist is usually completed within 24 hours and a copy will be sent to both to you and the referring physician.

The scanner is non-magnetic and non-claustrophobic.

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4.        How much X-Ray exposure is involved?

Virtual Colonoscopy requires very little X-ray exposure. The usual dose is a fraction of the natural radiation exposure we all receive each year from the sky and other environmental sources. When done every 3-5 years, a Virtual Colonoscopy provides an average X-Ray dose that is less than the additional radiation a person would receive from living at the same altitude as Denver during that same time period

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5.       Why do a Virtual Colonoscopy if I may need a regular Colonoscopy if an abnormality is found?

The vast majority of patients will be found to have a normal colon on Virtual Colonoscopy.  Depending upon the size criteria used for referring a patient with a colon polyp for regular Colonoscopy, only 2-5% of patients will require a regular Colonoscopy or Flexible Sigmoidoscopy after Virtual Colonoscopy.

The successful completion rate for a Virtual Colonoscopy is better than 98%.  However, numerous studies have shown the successful completion rate for regular Colonoscopy to be only 80-90%. That means 10-20% of patients undergoing regular Colonoscopy have to have the procedure redone.   Therefore, you are more likely to need a repeat  Colonoscopy after your regular Colonoscopy than after a Virtual Colonoscopy.

Virtual Colonoscopy is only a fraction of the cost of regular Colonoscopy and, without the risks of perforation or anesthesia complication, it is safer.  Now that Virtual Colonoscopy has been shown to be equal or superior to regular Colonoscopy, it is more cost-effective and safer to have your colorectal cancer screening done by Virtual Colonoscopy and then proceed with regular Colonoscopy only for those who have documented polyps or tumors.

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6.      Who is not a candidate for Virtual Colonoscopy?

Patients with the following condition should be sent for Optical Colonoscopy:

A.     Patients with a previous history of polyps or familial polyposis where there is a high likelihood of finding new polyps requiring excision.

B.     Patients with a history of colon cancer.

C.     Patients with Ulcerative Colitis where a biopsy should be done to evaluate dysplasia.

D.     Patients over 300 lbs.

E.      Patients who are pregnant

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7. Who will read my Virtual Colonoscopy?

Proper interpretation of a Virtual Colonoscopy requires great skill. Our radiologists are extensively trained and experienced in the interpretation of Virtual Colonoscopy. If a questionable abnormality is found, your scan is also reviewed by The Boston Diagnostics Center for Virtual Colonoscopy (, nationally renowned academic experts in the field of Virtual Colonoscopy.  They have published much of the medical research on Virtual Colonoscopy and lecture around the world.  When you combine Princeton Longevity Center's highly skilled staff with our radiologists' unsurpassed expertise in the interpretation of 3-D Virtual Colonoscopy you can feel secure that your Virtual Colonoscopy is among the best available anywhere.

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8.      What about those ads I hear from other centers offering discount prices for Virtual Colonoscopy?

You may hear radio advertisements from other centers that offer discounted rates for Virtual Colonoscopy.  These centers typically use less expensive room air insufflation which is more uncomfortable, and have their scans read by in-house radiologists whose expertise and experience can not compare to the radiologists reading your 3-D Virtual Colonoscopy scan at the Princeton Longevity Center. 

We strongly believe you should have a scan that is of the highest technical quality, read by radiologists with the most expertise and is as safe and comfortable as possible.  If you agree that the choice of where to have your Virtual Colonoscopy done should be based on experience and quality, not price, your choice is clearly Princeton Longevity Center.

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9.      Will insurance reimburse the patients for Virtual Colonoscopy?

In our experience, many patients are covered.  Iinsurance carriers have very diverse coverage policies.  As with other procedures, the reasons for the referral can also play a role in reimbursement decisions.  Our staff will be happy to call your insurance carrier to verify your coverage prior to making your appointment. 

At this time, Medicare does not yet cover Virtual Colonoscopy as a screening test.
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10. How do I make an appointment for a Virtual Colonoscopy?

Simply call us and our Patient Service Coordinators will take it from there.   Our staff is here to make it as easy as possible for you.  They can answer any questions you may have.  They will ensure that you are completely cared for from explaining the procedure and prep to ensuring that you receive your final report.  They will also be happy to assist you with verifying your insurance coverage and providing you with the materials to file a claim with your insurance carrier.

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