Getting Ready for Your Virtual Colonoscopy (VC)
(VC PEG Prep with Oral Contrast)
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 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
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.
If you schedule 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 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
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
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
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 (a laxative 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 agents
help 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 as you want unless you
are on a fluid restriction by your doctor. If
you are on a fluid restriction, please keep
this in mind as you plan for the day. The
GoLYTELY® described below does not
count toward this restriction. Drink only
clear liquids for breakfast, lunch, dinner,
and snacks. Do not eat any solid foods.
Drink plenty of fluid to avoid dehydration.
Avoid red or purple liquids (i.e., red Jell-O ,
cranberry juice, purple sports drinks). Clear
Gatorade , Powerade (we suggest
sports drinks with electrolytes to
help with hydration)
Water, tea, or coffee (no cream or
milk; sugar or honey is okay to add)
Vitaminwater , Crystal Light
Jell-O , Popsicles (no fruit or
Bouillon or broth (chicken, beef, or
Apple, white cranberry, or white
grape 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
How to Prepare GoLYTELY® Solution
• Please read the directions on the
GoLYTELY® bottle. Add water to
the “fill” mark on the bottle. Shake
it until all the powder is dissolved.
Do not add ice. Do not add any
other liquids or flavors except, if
desired, two packets of Crystal
Light® yellow lemonade powder
with Nutrasweet®. You may also try
to flavor by the glass, instead of
adding the Crystal Light® Lemonade
powder to the entire bottle, in case
you do not like it. Or, you may drink
the GoLYTELY® with no flavoring.
• You may find it tastes better if it is
chilled. Refrigerate, but do not add
ice. Because you are drinking a
large amount of liquid quickly, you
may become chilled. This is normal.
It can help if you wear warm
clothing, cover up with a blanket
warmed in the dryer, or drink it at
Bowel Prep Instructions: If you take other
medicines, don’t take them while drinking
GoLYTELY®. Take them at least 1 hour
before starting GoLYTELY® or at least 1
hour after you are done drinking the
GoLYTELY®. If you are under a fluid
restriction from your doctor, please note that
the GoLYTELY does not count towards
this restriction. GoLYTELY is not
absorbed by your colon, it just flushes
If you wish, you may put the GoLYTELY®
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 sunlight.
Step 1 – At 8 AM or before: Take
the four Bisacodyl® tablets (5 mg
each) with 1 glass (8 ounces) of clear
liquid. Do not chew or crush them.
Do not take them within 1 hour of
taking an antacid. This will gently
move your bowels 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 – Start anytime between 12
Noon and 2 PM: Be sure to prepare
the entire bottle of GoLYTELY® as
instructed above. Please note that it
ξ Drink with a straw to lessen the taste
ξ Try gum or clear hard candy
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
may take some people longer to drink
GoLYTELY®, so adjust the start time
based on how well you think you will
be able to tolerate the prep. Keep in
mind that you should try to be cleaned
out of stool by about 6 pm.
Start to drink one 8-ounce glass every
10 minutes. If you feel sick to your
stomach, stop drinking until the nausea
passes. Begin to drink again, but at a
slower rate (one 8-ounce glass every
About one hour after you start to drink
the GoLYTELY® you will likely begin
to have diarrhea. You will want to
stay close to a bathroom. You may
have some cramping in your lower
abdomen. This is normal. If you start
to have severe, steady stomach pain,
get lightheaded or dizzy, or you don’t
expel any of the GoLYTELY®, call
your primary care doctor.
When you have finished half of the
bottle of GoLYTELY®, you may stop
if your bowel movements are watery
and free of solids (flecks are OK). The
color may be clear to yellow, green, or
tan, but must be see-through. If your
bowel movements are not as described,
continue to drink the GoLYTELY®
until you feel your bowels are cleaned
out well. Most people will only need
to drink half the bottle of
GoLYTELY®, but some may need to
drink the entire bottle to clean out the
colon and get the best exam.
If you are done drinking the
GoLYTELY® by 6 PM, then
Step 3 – At 7 PM: 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. You
may keep drinking clear liquids as
Step 4 – At 9 PM: 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
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 contrast.
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
fast unless you want to.
If you are not able to complete the time
schedule on the previous page
If at 6 pm you still have more GoLYTELY®
to drink and are not cleaned out of stool,
keep drinking it. One hour after you’re
finished, drink the barium sulfate (Step 3).
Two hours after that, drink the Omnipaque
(iohexol) (Step 4).
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.
Bowel Prep Done!!!
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
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 is 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
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 doctor 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
If you are in need of immediate medical
help, call 911 or go to the nearest
If you need to reschedule for any reason
please call 608-263-9729.
The Spanish version of this Health Fact for
You is #6293s.
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#6293