Click a topic to jump down the page.
 Introduction
to Virtual Colonoscopy (CT Colonoscopy)
What
is the rationale for the test?
What
are the guidelines for study interpretation?
Does
BWH offer training for radiologists?
How
do I bill a virtual colonoscopy?
Should
I buy a virtual colonoscopy workstation?
What
are the current practice guidelines?
References
Introduction to Virtual Colonoscopy (CT
Colonography)
CT colonography (virtual colonoscopy) is a promising new method
for detecting colorectal polyps and cancers. Air or carbon dioxide
is insufflated into a cleansed colon in order to acquire high resolution,
thinly collimated helical CT slices. The slices are then examined,
in conjunction with three-dimensional reconstructions of the colon,
for the presence of polyps or tumors. Research at BWH, MGH, UCSF,
the Mayo Clinic and elsewhere has shown that CT colonography is
nearly or as accurate in detecting polyps as conventional endoscopic
colonoscopy, the gold standard for colorectal screening, and more
accurate than barium enema, formerly the leading alternative to
endoscopic colonoscopy. In addition, many patients report that
the CT colonography technique is more comfortable than either endoscopic
colonoscopy or barium enema. CT colonography is therefore best
suited and highly recommended for those patients who are unable
or unwilling to undergo conventional colonoscopy.
What is the rationale for the
test?
Colorectal cancer (CRC) is the second most common cause of cancer-related
death in the United States. Each year, 65,000 people in the United
States die from the disease, while 155,000 new cases are diagnosed.
Multiple studies demonstrate that CRC usually develops from a precursor
lesion, most commonly a form of growth known as a adematous polyp.
Early detection of CRC improves survival dramatically. When detected
in its earliest stage, CRC has a five-year survival rate of 85-100%,
while in later stages the survival rate drops to 50% or lower.
Furthermore, detection of precancerous polyps may prevent cancer
from developing completely.
For those reasons, colorectal screening is strongly recommended
for all individuals over the age of fifty, particularly those with
a family history of colorectal cancer. However, many patients are
unable or unwilling to undergo endoscopic colonoscopy, and for
those patients, CT colonography is often appropriate. Several studies
have evaluated the accuracy of colonography screening in symptomatic
patient groups or patients with known risk factors for colorectal
cancer. Those studies have found that colonography has a sensitivity
of 75-91% and specificity of 90+% in comparison to conventional
colonoscopy for detection of polyps that pose a greater than 1%
chance of becoming cancerous (i.e. those > 1 cm in size).
What are the guidelines for study
interpretation?
Please refer to our guidelines page.
Does BWH offer training for radiologists?
Yes. The Brigham, in conjunction with Harvard Medical School, offers
a two-day course in virtual colonoscopy, focused on how to perform
and interpret virtual colonoscopy. The course includes substantial
hands-on experience in reading virtual colonoscopy studies. You
may read more or register for the course here.
How do I bill virtual colonoscopy?
As a screening test, CT colonography is not covered by nearly any
health insurance plan. Patients pay for screening, and must sign
a waiver before the procedure. However, there is a second kind
of CT colonography, diagnostic CT colonography, for patients
with certain symptoms. Diagnostic CT colonography is billed as
a CT of the abdomen and pelvis with 3D reconstructions. There
several differences
between screening and diagnostic colonography.
Coding for CT colonography is the same following a failed colonoscopy.
Asymptomatic patients who come for CTC after failed colonoscopy
are still considered screening, unless symptoms are discovered
or created by the failed colonoscopy (e.g. an obstructing mass).
A waiver is still necessary,
and should be signed before colonoscopy, not after.
Virtualcolonoscopy.org contains a billing
guide for Partners affiliates.
Should I buy a virtual colonoscopy
workstation?
A number of companies offer specialized software for interpreting
CT colonography. The software may come as part of a 3D workstaiton,
or as a standalone package. CTC software can be an invaluable aid
to interpretable, allowing reformatted views, 3D models of suspected
polyps, or endoscopic views of the colon to be created and manipulated
in real-time.
What are the current practice
guidelines?
Please refer to our guidelines page.
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