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Dr. Kenneth Falchuk>>> So when we talk about screening patients or taking care of patients
with what we call bowel symptoms, diarrhea, pain, change of bowels, there are ways to
evaluate this. It does not have to always be done with an invasive procedure such as
a colonoscope. It can also be done with an x-ray.
There is a technique that is called virtual colonoscopy, it should be called colonoscopy
because one is not looking with a light but one is looking with an x‑ray and it allows
us to see the lining of the colon.
The virtuality means that it has been done as the patient is there, on sight, on target,
in an active fashion where the physician usually, for the most part, a radiologist is looking
at the colon, the whole lining of the colon dynamically as some contrast, which is something
that allows him or her. It could be a him or her radiologist to outline the surface
of the colon and then take x-rays of the whole colon, which is quite a large organ. It measures
5 feet or longer and has a lot of curves to it.
So, the virtual without having to be put a tube into the colon and then push it throughout
the whole length of the colon, allows the radiologist with a contrast, a liquid that
they introduced through a very small little tube in the opening of the *** called the
*** and then take pictures.
It does not cause that much discomfort. There could be a little discomfort when air is put
in. There is no need for the patient to receive intravenous sedation drugs to fight pain or
prevent pain, I should say. This technique is therefore non‑invasive, hardly any side
effects. It allows the physician to evaluate the whole length of the colon and see if there
is something causing a change of the lining or of the opening, we call it the lumen, it
is narrow or not.
Similar to colonoscopy, one can see the whole colon but the negatives is that if the colon
is not well-prepared, that means the cleansing that is given to the patient, which is similar
to one that is used for colonoscopy, is not excellent, does not achieve a perfect clean-out,
then there are changes that can be noticed that may be artifacts.
Stool that sits on the lining of the colon and then the radiologist, contrary to a specialist
like myself, a gastroenterologist, is unable to go to that site so “touch it with the
instrument or probe and move it around or remove it”. So what happens is that reports
come back to us, the treating physician, gastroenterologist or internist, or a surgeon, who request the
study saying “we do not see anything large, but we see something on the surface all the
way around, right side of the colon that may be stool but it could be a polyp,” and the
confidence of this technique is 95% so we could miss polyps that are small, under 0.05
or 5 mm, that means less than a half an inch.
Therefore, we suggest he do another one, clean the patient better or if not do a colonoscopy.
So therein you can start seeing there is an issue about virtual colonoscopy whereby you
will still have to clean out the patient. It is not that expensive, yes it is not truly
invasive, but you may not be able with certainty to fully evaluate the lining of the colon,
there are artifacts that are called and beyond that no therapy, no treatment can be offered
to the patient. So if there is a polyp there, it could have been removed.
On the contrary, if a colonoscopy would have been done then if there is a polyp, you will
remove it, everything is done, no need to repeat anymore studies and ultimately or may
be less costly and definitely more effective.
There are also patients were virtual colonoscopy is truly advantageous in those who have a
narrowing or there are patients with whom colonoscopy was not totally successful for
many reasons, technical, patient discomfort and so on and the whole colon could not be
fully evaluated.
So, there is where virtual colonoscopy plays an important role as an adjunct, as an extra
study that allow to finish, finalize, the complete evaluation of our patient.