# What's the poop on CT Colonography? **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [March 30, 2010, 5:15pm UTC](https://boards.straightdope.com/t/whats-the-poop-on-ct-colonography/534346 "2010-03-30T17:15:34Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![teela\_brown](https://avatars.discourse-cdn.com/v4/letter/t/d9b06d/32.png) [@teela\_brown](https://boards.straightdope.com/u/teela_brown)\ **Post date:** [March 30, 2010, 5:15pm UTC](https://boards.straightdope.com/t/whats-the-poop-on-ct-colonography/534346/1 "2010-03-30T17:15:34Z")
I’ve heard about this procedure. It’s a “virtual colonoscopy”, and it’s non-invasive. If it’s reliable, then I’m sure just about everyone will opt for it over getting a tube snaked up their butt. But of course, insurance companies balk at covering it. But is it reliable? Has anyone had it? ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [March 30, 2010, 5:36pm UTC](https://boards.straightdope.com/t/whats-the-poop-on-ct-colonography/534346/2 "2010-03-30T17:36:19Z")
In order for a procedure such as CT colonoscipy to be deemed reliable it must be compared a number of times against the old reliable procedure and yield similar or better results. I am not sure there have been enough such comparisons done (it would have be hundreds, if not thousands, of such) If it yields equal results then which one to choose (ideally) comes down not to patient preference but rather dollars and risk - CT colonoscopy does, after all, involve radiation exposure. While I agree that standard colonoscopy prep is no fun, I’m not too keen on needless radiation exposure, either. One possible drawback to the CT version is that you can only _look_ - if something odd is found you’re back to a second procedure. Standard colonoscopy allows docs to snip off tissues samples easily, and even deal with minor issues as they are actually in there with tools. ---
**Author:** ![chappachula](https://avatars.discourse-cdn.com/v4/letter/c/d2c977/32.png) [@chappachula](https://boards.straightdope.com/u/chappachula)\ **Post date:** [March 30, 2010, 5:44pm UTC](https://boards.straightdope.com/t/whats-the-poop-on-ct-colonography/534346/3 "2010-03-30T17:44:29Z")
The “Virtual” checkup suffers the same problem as the old tube-up-the-butt method: The night before, you still have to do the prep, drink the iccky stuff and then shit your life away all night. Plus-- if they do find something, you have to do it **all over again** , so they can stick the tube up your butt and cut off the polyp. What’s the advantage for the patient? ---
**Author:** ![Attack\_from\_the\_3rd\_dimension](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@Attack\_from\_the\_3rd\_dimension](https://boards.straightdope.com/u/Attack_from_the_3rd_dimension)\ **Post date:** [March 30, 2010, 5:47pm UTC](https://boards.straightdope.com/t/whats-the-poop-on-ct-colonography/534346/4 "2010-03-30T17:47:02Z")
Similar detection rates for larger polyps. (NEJM [http://content.nejm.org/cgi/content/short/357/14/1403](http://content.nejm.org/cgi/content/short/357/14/1403) , Radiology [http://radiology.rsna.org/content/224/2/383.full](http://radiology.rsna.org/content/224/2/383.full)). There is, of course some risk associated with radiation in any CT study, and the risk of CT Colongoraphy is calculated at 5 / 10,000 lifetime chance of getting cancer from the study for a 50 year old person. ([ARCH INTERN MED/ VOL 169 (NO. 22), DEC 14/28, 2009](http://archinte.ama-assn.org/content/vol169/issue22/index.dtl)) But there seems to be less risk of colon perforation, presumably because it’s just gas in the colon, but no gear. Generally it seems less uncomfortable than other methods ([http://www.ajronline.org/cgi/content/abstract/181/4/913](http://www.ajronline.org/cgi/content/abstract/181/4/913)). ---
**Author:** ![Attack\_from\_the\_3rd\_dimension](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@Attack\_from\_the\_3rd\_dimension](https://boards.straightdope.com/u/Attack_from_the_3rd_dimension)\ **Post date:** [March 30, 2010, 5:50pm UTC](https://boards.straightdope.com/t/whats-the-poop-on-ct-colonography/534346/5 "2010-03-30T17:50:46Z")
> [@Broomstick](#): > > In order for a procedure such as CT colonoscipy to be deemed reliable it must be compared a number of times against the old reliable procedure and yield similar or better results. I am not sure there have been enough such comparisons done (it would have be hundreds, if not thousands, of such) > > If it yields equal results then which one to choose (ideally) comes down not to patient preference but rather dollars and risk - CT colonoscopy does, after all, involve radiation exposure. While I agree that standard colonoscopy prep is no fun, I’m not too keen on needless radiation exposure, either. > > One possible drawback to the CT version is that you can only _look_ - if something odd is found you’re back to a second procedure. Standard colonoscopy allows docs to snip off tissues samples easily, and even deal with minor issues as they are actually in there with tools. 3000 + patients in the NEJM study mentioned above, and you’re right about the fact that with CT they can’t do a quick biopsy “while they’re in the neighborhood”. ---
**Author:** ![Kent\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kent_clark/32/105_2.png) [@Kent\_Clark](https://boards.straightdope.com/u/Kent_Clark)\ **Post date:** [March 31, 2010, 1:07am UTC](https://boards.straightdope.com/t/whats-the-poop-on-ct-colonography/534346/6 "2010-03-31T01:07:56Z")
> [@chappachula](#): > > The “Virtual” checkup suffers the same problem as the old tube-up-the-butt method: > The night before, you still have to do the prep, drink the iccky stuff and then shit your life away all night. > Plus-- if they do find something, you have to do it **all over again** , so they can stick the tube up your butt and cut off the polyp. > > What’s the advantage for the patient? Yup, and yup. And as the [Guy Who Had a Colonoscopy](http://boards.straightdope.com/sdmb/showthread.php?t=416276&highlight=colonoscopy)I can tell you, the prep is the thing you hate the most. ---
**Author:** ![BrotherCadfael](https://avatars.discourse-cdn.com/v4/letter/b/977dab/32.png) [@BrotherCadfael](https://boards.straightdope.com/u/BrotherCadfael)\ **Post date:** [March 31, 2010, 1:38am UTC](https://boards.straightdope.com/t/whats-the-poop-on-ct-colonography/534346/7 "2010-03-31T01:38:15Z")
> [@chappachula](#): > > What’s the advantage for the patient? If you are on blood thinners, any invasive procedure requires you to stop taking them a few days before. However, you don’t just start and stop blood thinners willy-nilly - starting up again can be a fairly complicated routine involving several different medicines over a period of a week of so. In my case, this involves a week of self-administered injections. Avoiding all this rigmarole would be wonderful. I hope that when I am due for my next one four years from now, the virtual procedure will be routine. ---
**Author:** ![Rysdad](https://avatars.discourse-cdn.com/v4/letter/r/7cd45c/32.png) [@Rysdad](https://boards.straightdope.com/u/Rysdad)\ **Post date:** [March 31, 2010, 2:49am UTC](https://boards.straightdope.com/t/whats-the-poop-on-ct-colonography/534346/8 "2010-03-31T02:49:08Z")
One of the radiologists I work with mentioned that one drawback was that you can’t see anything in color–CT scans (X-rays) only provide grayscale images. Something that is, indeed, white or dark red, with no other anatomical difference, might appear normal on a CT scan. Another drawback that I can think of is that you’re dosing some sensitive areas with radiation. Young, fertile females might want to consider that. ETA: The colon itself appears mostly white during a colonoscopy. But a patch of something ‘whiter’ might be indicative of an underlying problem. ---
**Author:** ![Attack\_from\_the\_3rd\_dimension](https://avatars.discourse-cdn.com/v4/letter/a/b38774/32.png) [@Attack\_from\_the\_3rd\_dimension](https://boards.straightdope.com/u/Attack_from_the_3rd_dimension)\ **Post date:** [March 31, 2010, 3:27am UTC](https://boards.straightdope.com/t/whats-the-poop-on-ct-colonography/534346/9 "2010-03-31T03:27:46Z")
> [@Rysdad](#): > > One of the radiologists I work with mentioned that one drawback was that you can’t see anything in color–CT scans (X-rays) only provide grayscale images. Something that is, indeed, white or dark red, with no other anatomical difference, might appear normal on a CT scan. > > Another drawback that I can think of is that you’re dosing some sensitive areas with radiation. Young, fertile females might want to consider that. > > ETA: The colon itself appears mostly white during a colonoscopy. But a patch of something ‘whiter’ might be indicative of an underlying problem. 30 year old female risk is calculated at 6 / 10,000 in the study cited above. Nothing to sneeze at, especially if you anticipate multiple studies over your lifetime. ---
**Author:** ![crazyjoe](https://avatars.discourse-cdn.com/v4/letter/c/f14d63/32.png) [@crazyjoe](https://boards.straightdope.com/u/crazyjoe)\ **Post date:** [March 31, 2010, 3:45pm UTC](https://boards.straightdope.com/t/whats-the-poop-on-ct-colonography/534346/10 "2010-03-31T15:45:43Z")
> [@Rysdad](#): > > One of the radiologists I work with mentioned that one drawback was that you can’t see anything in color–CT scans (X-rays) only provide grayscale images. Something that is, indeed, white or dark red, with no other anatomical difference, might appear normal on a CT scan. > > Another drawback that I can think of is that you’re dosing some sensitive areas with radiation. Young, fertile females might want to consider that. > > ETA: The colon itself appears mostly white during a colonoscopy. But a patch of something ‘whiter’ might be indicative of an underlying problem. Really? I have pictures of my colonoscopy (hey, they were in my file and I asked to see them) and it looked about like how the inside of a clean colon could be expected to look, with a little inflammation, but with visible blood vessels and all. I would not have described it as white. ---
**Author:** ![Rysdad](https://avatars.discourse-cdn.com/v4/letter/r/7cd45c/32.png) [@Rysdad](https://boards.straightdope.com/u/Rysdad)\ **Post date:** [April 1, 2010, 1:34am UTC](https://boards.straightdope.com/t/whats-the-poop-on-ct-colonography/534346/11 "2010-04-01T01:34:16Z")
> [@crazyjoe](#): > > Really? I have pictures of my colonoscopy (hey, they were in my file and I asked to see them) and it looked about like how the inside of a clean colon could be expected to look, with a little inflammation, but with visible blood vessels and all. I would not have described it as white. Well, as best I can describe it, they’re very pale-colored. Not really pink, but more whitish. And, yes, there are blood vessels. I’m just trying to say that something off-colored wouldn’t _be_ off-colored in a CT scan—just gray. I’ve seen too many live pictures of people’s squishy bits to count. I first notice something odd by a shape that shouldn’t be there, and then the color.