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Getting Ready for Your Virtual Colonoscopy (VC) (Routine VC Prep) (7560)

Getting Ready for Your Virtual Colonoscopy (VC) (Routine VC Prep) (7560) - Clinical Hub, Patient Education, Health and Nutrition Facts For You, Diagnostic Tests, Procedures, Equipment



Getting Ready for Your Virtual Colonoscopy (VC)
(Routine VC Prep)

What is Virtual Colonoscopy?
Virtual Colonoscopy (VC), also referred to
as CT colonography, is a less-invasive, safe
exam used for colon polyp screening. The
entire colon lining can be seen with VC. A
computed tomography (CT) scan creates a
3-D picture of the inside of your colon
which helps the doctor to “fly” through the
inside of the colon without having to insert a
scope. The main purpose of this exam is to
screen for growths (polyps) in the lining of
the large intestine (colon and rectum).
Screening for colorectal cancer and colon
polyps should start at age 50. If you have a
first-degree relative (a parent, brother, sister,
or child) with colorectal cancer, your doctor
may decide to start screening earlier than
age 50.

If a large polyp or growth is found in your
colon, a standard colonoscopy may be
needed to remove the polyp. “Large” polyps
are those 1 cm (about ⅜ inch) or greater and
should be removed because they have a
higher chance of turning into cancer. A
growth of this size is present in less than 5%
of all patients. A nurse will set up the
standard colonoscopy, if needed. If this
occurs, someone needs to drive you home.
By scheduling the standard colonoscopy on
the same day or next day, a second bowel
prep is not needed.

Doctors at UW Health can also watch a
small colon polyp over time. Smaller
polyps, 6 mm to 9 mm (about ⅓-¼ inch),
can be safely watched by having a follow up
VC exam in 3 years. But small polyps can
also be removed by standard colonoscopy,
the same day or later, if you would like.

VC also allows the doctor to take a limited
look outside the colon for problems in the
abdomen and pelvis. This may help find
problems in the abdomen and pelvis such as
abdominal aneurysms, other cancers, or
conditions you may not have been aware of.
At many locations where VC is done, we
may also be able to do a CT BMD (bone
mineral density) exam to screen for
osteoporosis. If this is done, it is at the same
time as your VC exam with no extra scans
or cost.

Getting Ready for your VC Exam
If you would like to have the option of a
same-day standard colonoscopy if a polyp is
found, stop taking iron tablets five days
before the exam. If you would not be able
to have a standard colonoscopy the same
day because you do not have a driver, are on
blood thinners or anti-platelet medications,
or have other plans, you may continue
taking iron tablets. Iron tablets do not affect
the VC exam. If you have any questions or
concerns about stopping a medicine please
call your doctor. You may take all other
prescribed medicines before your VC (if you
have diabetes or take prescription blood
thinners or anti-platelet medications, see the
boxes on page 2).

Three days before the exam, try to avoid
foods that are digested slowly (corn,
popcorn, potato skins, nuts, fruits with skin
or seeds, uncooked or raw vegetables)
because they may interfere with your prep.

If you have Diabetes:

Please call your doctor to discuss how your diabetes medicine (oral diabetes pills and/or
insulin) doses should change before the VC.

Test your blood sugar more often the day before this test. Also check your blood sugar the
morning of your test. If your blood sugar level is low (less than 70 mg/dl) or if you have
symptoms, take some glucose tablets or drink 4 ounces of a clear liquid that contains sugar.
Always recheck your blood sugar level to make sure it stays above 70. We can still do the VC
unless you need to eat solid food to keep your blood sugar at a normal level. If the blood sugar
ever gets too high or too low and you can’t bring it back to normal, call your primary care or
diabetes doctor.

If you get Diverticulitis before your VC exam:

Call your doctor first for treatment. Then contact the VC office to reschedule your exam for at
least six weeks after your treatment is complete to allow your colon to heal.

If you take Prescription Blood Thinners or Anti-Platelet Medicines:

Do not stop taking them unless your doctor tells you to stop them. Some examples include:
Coumadin® (warfarin), Plavix® (clopidogrel), Effient® (Prasugrel), Pradaxa ® (Dabigatran). VC
is often recommended for patients taking these types of medications because it is felt to be too
great a risk to stop the blood thinner for a standard colonoscopy. VC can safely evaluate your
colon without stopping these medications. If a polyp is found that should be removed, we will
consult with your doctor who can set up the standard colonoscopy at a later date.

If your doctor tells you to stop your blood thinner or anti-platelet medicines so that you can have
a same-day standard colonoscopy if a polyp is found, you must discuss how long to stop the
medicine and any special instructions to do so safely with the doctor who prescribed the
medicine for you.

Please stop iron tablets 5 days before your VC exam, only if you will also be stopping the blood
thinner or anti-platelet medication. Otherwise you may keep taking iron.

The Day Before Your Exam (Prep Day)
Proper bowel cleaning is needed for the best
exam. To get a clean and empty colon you
will start to prepare the day before your
exam. Both a clear liquid diet and the
contents (laxatives and contrast medicines)
of the bowel prep kit are needed to clean out
the colon. The laxative helps clean out the
bowel for the exam. The contrast helps to
highlight any stool or fluid left in your colon
on the VC pictures.

Starting at midnight the entire day before
your exam (prep day), you may drink as
many clear liquids (see below) as you want
unless you are on a fluid restriction by your
doctor. If you are on a fluid restriction,
please speak with your doctor to make sure

Helpful Hints:
ξ Drink with a straw to lessen the taste
ξ For a sore bottom after a bowel
movement, cleanse with baby wipes
and apply a protective ointment such
as A+D® or Vaseline®. TUCKS®
medicated cooling pads may also
provide relief.

this prep is right for you. Drink only clear
liquids for breakfast, lunch, dinner, and
snacks. Do not eat any solid foods. Drink
plenty of fluid to avoid dehydration and
make the laxative work better. Avoid red or
purple liquids (i.e., red Jell-O , cranberry
juice, purple sports drinks). Clear liquids
 Gatorade , Powerade (sports drinks
with electrolytes are recommended
to help with hydration)
 Water, tea, or coffee (no cream or
milk; sugar or honey is okay to add)
 Vitaminwater , Crystal Light
 Bouillon or broth (chicken, beef, or
 Jell-O , Popsicles (no fruit or
cream added)
 Apple, white grape, or white
cranberry juice (no orange, tomato,
grapefruit, or prune juice)
 Soda such as Sprite , 7-Up , ginger
ale, or any cola
 Clear hard candy, gum
 Lemonade (with no pulp), iced tea
 Clear liquid protein drinks such as
Ensure Clear TM, or Resource

Follow the Bowel Prep medicine schedule.
If you take other medicines, take them at
least one hour before or at least one hour
after taking the laxative (magnesium citrate).
If you wish, you may put the magnesium
citrate and barium sulfate in the refrigerator.
Or, you may drink them at room
temperature. Do not put the Omnipaque
(iohexol) in the refrigerator and do not store
the bottle where it would be in direct

You may have as many clear liquids as you
like between each step and up until

 Step 1 – anytime in the morning
before 11AM: Take the two
Bisacodyl tablets (5 mg each) with
1 glass (8 ounces) of clear liquids.
Do not chew or crush them. Do not
take them within 1 hour of taking an
antacid. This will gently move your
bowels (6-8 hours after you take this
medicine) to help the laxative taken
in Step 2 work better. You can take
these tablets and still do normal
activities because they rarely cause

 Step 2 – begin this step anytime
between 2 and 6 PM: Keep in
mind that the later you start the
laxative, the later you may be up
having bowel movements. Drink
one bottle (296 mL) of
magnesium citrate. Follow this
with at least 4 to 6 cups of clear
liquids before Step 3. This is a
laxative, so you should begin to
have closely spaced bowel
movements. You will want to be
near a restroom. The time it
takes for the laxative to start
working varies for each person.
Wait at least 2 to 3 hours from
the time you took the first bottle
of magnesium citrate before
going on to Step 3.

 Step 3 – between 4 and 9 PM:
There should be 2-3 hours between
drinking the first bottle of
magnesium citrate and the start of
Step 3.
o Drink the entire 225 mL bottle of
liquid barium sulfate suspension
found in the prep kit. This is a
contrast medicine used to highlight
any leftover stool on the CT images.
There is no lactose in the barium.
o Drink the second bottle (296 mL) of
magnesium citrate. This is a laxative
and will continue the process of
cleaning out the colon. Follow this
with at least 4 to 6 cups of clear
liquids before Step 4. You can drink
the 4 to 6 cups of clear liquids
quickly, or you can stretch the clear
liquids out over the next 2 to 3 hours
if you are feeling full. Step 4 can
begin 2 to 3 hours after drinking the
second bottle of magnesium citrate.
 Step 4 – between 6 and 11 PM:
Step 4 should begin 2-3 hours after
drinking the second bottle of
magnesium citrate.

Omnipaque (iohexol) is another
contrast medicine that helps
highlight fluid in your colon. The
bottle says it is for “injection,” but
this medicine can also be taken
orally, meaning you drink it. We
want you to drink this medicine so
that it will be in your colon by the
next morning for your exam.

The plastic bottle has a pull-tab on
the top, but you do not need to pull
this. Instead, twist the entire top to
remove it. Also remove the black
rubber stopper before drinking the

Drink the entire 50 mL bottle of
Omnipaque (iohexol) 350 mgI/mL.
You may mix it in 8 ounces of clear
juice, water, or soda and drink. Or,
drink the Omnipaque and then
follow it with 8 ounces of clear juice,
water, or soda. You do not need to
drink it quickly unless you want to.

You may keep drinking clear liquids until

The Day of Your Exam
Do not eat or drink anything after
midnight the day of your exam until you
are told to do so after your exam. You
may take your daily medicines as prescribed
with small sips of water. If you haven’t
been able to have a bowel movement or to
finish the prep kit, please call the VC office
to ask if the exam can still be performed or
if we need to reschedule the exam for a later

If you have diabetes, test your blood glucose
level more often when you can’t eat as well
as before your exam. You should adjust
your insulin or oral diabetes pills as
discussed with your doctor. Go back to your
normal schedule after you get the exam
result phone call and are able to eat again. If
your blood glucose level is low (less than 70
mg/dl) or you have symptoms, please drink
a clear liquid that has sugar in it or take
glucose tablets. Always recheck your blood
sugar level to make sure it stays above 70.
We can still do the exam unless you need to
eat solid food to maintain your blood
glucose. It is better to maintain your blood
glucose than to have the exam. We can
always schedule your VC in the future.

You do not need to have a family
member or friend drive you to and from
the VC exam, as you are not given any
 Bowel Prep Done!!!

medicine that will make you sleepy. If
you need a standard colonoscopy the
same day, then you will need to arrange
for someone to drive you for that test.

During the Exam
The VC exam most often takes 20 minutes
or less to do, but allow up to 45 minutes to
change your clothes and talk with the CT
technologist (tech). You do not need pain or
sedation medicine or an IV for this exam.
You are asked to change into a hospital
gown and then taken to a CT exam room
where you lie on the CT exam table. A
small tube is gently placed a very short
distance into your rectum (this feels like
having a digital rectal exam). Carbon
dioxide will be placed slowly into your
colon. The exam should not be painful,
though you may have some abdominal
fullness, discomfort, or cramping during the
exam. You may feel the urge to have a
bowel movement. These feelings should go
away as soon as the exam is over. Pictures
are taken of your abdomen and pelvis while
you are lying on your back and then on your
stomach. You are asked to hold your breath
for about 10 seconds while the CT scanner
takes pictures.

After the Exam
You are asked to give the CT tech a phone
number where the VC team can call you
with your colon results. Many patients go
back to work or other activities after the
ξ If you wish to have a polyp removed
the same day as your VC, please do
not eat or drink until you hear from
us. If you need to have a standard
colonoscopy, the VC team can set up
this second exam for the same day as
long as you have not eaten or had
any liquids to drink.
ξ If you take prescription blood
thinners, anti-platelet medicines, or
do not wish to have a same-day
standard colonoscopy, you may go
back to your normal diet right after
the exam. If a polyp is found that
should be removed, a standard
colonoscopy is set up at a later date
by your doctor’s office.

A VC team member will call you with the
colon results in about two hours. If you do
not have colon polyps, you are told to go
back to your normal diet and any medicines
you may have stopped. If you have colon
polyps, a member of the VC team will
review options with you and help set up
further care as needed.

If any other problems are seen outside your
colon, the results are sent to your doctor in
the full VC report. If you have not heard
from your doctor about other results within
2 weeks, we suggest you call his or her
office to follow up.
For more information on the virtual
colonoscopy exam and prep, please see our
video at uwhealth.org/vcprep

VC Program Assistant: 608-263-8587
VC Nurse: 608-263-9630

If you have an urgent concern after normal
business hours please contact your primary
care doctor’s on call service. If your
referring physician is from outside the UW
Health system, you may call the paging
operator for urgent VC related concerns at
608-263-6400 and ask for the radiology
resident on-call.

If you are in need of immediate medical
help, call 911 or go to the nearest
Emergency Room.

If you need to reschedule for any reason
please call 608-263-9729.

Spanish Version of this HFFY is #7560s

Your health care team may have given you this information as part of your care. If so, please use it and call if you
have any questions. If this information was not given to you as part of your care, please check with your doctor. This
is not medical advice. This is not to be used for diagnosis or treatment of any medical condition. Because each
person’s health needs are different, you should talk with your doctor or others on your health care team when using
this information. If you have an emergency, please call 911. Copyright 2/2017. University of Wisconsin Hospitals
and Clinics Authority. All rights reserved. Produced by the Department of Nursing HF#7560