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Physicians Guide to
Virtual Colonoscopy
With the publication of
the study by Pickhardt and the
accompanying editorial in the December 2,
2003, issue of the New England Journal of Medicine, Virtual Colonoscopy is now
established as equal or superior to Optical Colonoscopy in sensitivity for
detecting colorectal tumors and polyps. In addition, Virtual Colonoscopy
is clearly superior at detecting incidental extra-colonic abdominal and pelvic
disease.
To view the NEJM articles, click on the
links above.
The information below is intended to help you answer your patient's questions
about Virtual Colonoscopy.
1. What are the indications for Virtual Colonoscopy?
2. What type of Prep is required?
3. What should patients expect during the procedure?
4. How much X-Ray exposure is involved?
5. Why do a Virtual Colonoscopy if an Optical Colonoscopy
will be needed for any abnormalities found?
6. Which patients are not candidates for Virtual
Colonoscopy?
7. How much does Virtual Colonoscopy cost?
8. Will insurance companies reimburse Virtual
Colonoscopy?
9. How do I refer a patient for Virtual Colonoscopy?
1.
What are the indications for Virtual
Colonoscopy?
The Pickhardt study shows that the sensitivity of Virtual Colonoscopy is
comparable to, or even exceeds, Optical Colonoscopy for clinically significant
polyps. Therefore, Virtual Colonoscopy can now be considered a valid tool for
routine screening of patients at low or intermediate risk for polyps and
colorectal cancer. (For those patients at high risk, such as patients with
previously documented polyps or cancer, an Optical Colonoscopy is advised)
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 is unable
to reach the cecum 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 to the cecum.
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, such as patients with
mild dementia.
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. If
the test shows a polyp, they are willing to accept Optical Colonoscopy once
they know there is a need for the procedure.
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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 may take either 4 oz
of Fleet Phosphasoda in divided doses or the LoSoPrep kit by EZEM which uses
4 oz of Magnesium Citrate and 4 Dulcolax tablets. 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 patients expect during the
procedure?
The Virtual Colonoscopy is a quick and easy procedure. A 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. Insufflation 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 for the patient 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.
Adequate insufflation is generally achieved in less than 5 minutes. The
patient then undergoes two scans from the rectum to the diaphragm, one in the
supine position and then in the prone position. The change in position allows
for movement of any retained stool or fluid, improving the sensitivity of the
procedure. Each scan is a single breath-hold scan that takes approximately
20-30 seconds. Because the CO2 is quickly absorbed, patients can expect to
feel entirely back to normal by the time they leave the scanner suite.
The Virtual Colonoscopy itself will generally take less than 10 minutes. In
addition, our nursing staff will review the patient’s history prior and
provide any explanation or reassurance the patient needs prior to the
procedure. Following the test, patients are welcome to spend a few minutes in
our lounge area where a breakfast or light snack is provided. It takes about
15 minutes to process the images at which time patients are welcome to meet
with one of our physicians for a preliminary fly-through of the colon. The
final report from our radiologist is usually completed within 24 hours and a
copy will be sent to both the patient and the referring physician.
The EBT scanner is non-magnetic and non-claustrophobic.
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4.
How much X-Ray exposure is involved?
A CT Virtual Colonoscopy is approximately 20% lower than the X-Ray dose of
a typical double-contrast Barium Enema.
EBT scans are generally 1/5th to 1/10th the dosage
of helical or mutli-slice CT scans.
When done every 3-5 years, an EBT Virtual Colonoscopy provides an average
X-Ray dose which is approximately the same or less than the background
radiation dose that a person at sea-level will receive annually from naturally
occurring radiation sources.
(For more information on
the radiation doses from various CT and EBT scans, please ask our office for
our publication on “EBT Scans and Radiation Exposure”)
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5.
Why send a patient for Virtual Colonoscopy
if they are going to need an Optical Colonoscopy if an abnormality is found?
The vast majority of low and intermediate risk 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 Optical Colonoscopy, only
2-7% of patients will require an Optical Colonoscopy or Flexible Sigmoidoscopy
after Virtual Colonoscopy.
The successful completion rate for a Virtual Colonoscopy is better than 98%.
Numerous studies have shown the successful completion rate for Optical
Colonoscopy to be only 80-90%. Therefore, a patient is more likely to need
a repeat Optical Colonoscopy after their first Optical Colonoscopy than after
a Virtual Colonoscopy.
Virtual Colonoscopy is only a fraction of the cost of Optical
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 Optical Colonoscopy, it is more cost-effective and safer for your
patients to have their colorectal cancer screening done by Virtual Colonoscopy
and to refer only those with documented polyps or tumors for Optical
Colonoscopy for polypectomy or biopsy.
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6.
Which patients are not a candidate for
Virtual Colonoscopy?
Patients with the following condition should be sent for Optical
Colonoscopy:
A.
Patients with a 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.
How much does a Virtual Colonoscopy cost?
The cost is $1,200.00. This less than 1/3rd the cost of a
typical Optical Colonoscopy.
Your patients may hear radio advertisements for other centers that offer
discounted rates for Virtual Colonoscopy. These centers typically use
multi-slice CT scanners that deliver higher radiation doses, 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 patient’s 3-D Virtual Colonoscopy
scan at the Princeton Longevity Center. We strongly believe that for you
to feel comfortable referring your patient for a Virtual Colonoscopy you need
to know that your patient will 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 your patients understand their choice
of where to have their scan done should be based on experience and quality, not price, that
choice is clearly Princeton Longevity Center.
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8.
Will insurance reimburse the patients for
Virtual Colonoscopy?
In our experience, most patients are covered. In many cases, our patients
have received close to 100% reimbursement.
As you know, insurance 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 patient’s
insurance carrier for them to verify their coverage prior to making their
appointment.
At this time, Medicare does not yet cover Virtual Colonoscopy.
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9.
How do I refer a patient for Virtual Colonoscopy?
Simply have your office or your patient call us and our Patient Service
Coordinators will take it from there. Our staff is here to make it as easy
as possible for your office and your patients. They can answer any questions
your patients may have. They will ensure that your patient is completely
cared for from explaining the procedure and prep to ensuring that they receive
their final report and have all their questions answered.
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