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Question for the panel

califvader's picture
califvader
Posts: 108
Joined: Aug 2010

a colonoscopy will give you results of the large intestine. what about the small intestine? i assume you can get cancer there as well. what tests/procedures are there to check your small intestine?

steved
Posts: 835
Joined: Apr 2004

Admit is cut and paste from elsewhere but seems a sensible answer:

There are now a number of approaches to investigating the small bowel, both endoscopically with developments in optical as well as capsule endoscopy, and in imaging where MRI is leading the development of small bowel imaging.

The small bowel is seen well during routine abdomino-pelvic CT, particularly if oral contrast has been given. This may be either positive (very dilute barium or Gastrografin) or more often negative (water) as then the bowel wall may be highlighted with intravenous contrast enhancement to give more specific information about bowel wall vascularity and changes. Small bowel abnormalities are often picked up during CT, but begs the question as to whether this is the examination of choice for targeted investigation.

In acute small bowel obstruction, CT is the examination of choice. The problem with the plain film is that one can only see the small bowel when it is gas filled, and there is seldom enough gas to determine the exact site and nature of the obstruction. However, fluid in the small bowel provides excellent contrast for CT, which can not only confirm obstruction, but also show the site and often the nature of the obstruction as well as assessing bowel viability(1).

Often the cause and presence of the obstruction are known, and the clinical problem is whether to operate early or wait. CT is still indicated if there is concern as to bowel viability, but if not then an alternative approach, giving 100mls of Gastrografin orally and taking a film after 4hrs, may be used to divide those in whom the contrast is in the colon and it is safe to leave, and those in whom the contrast is held up in the small bowel who probably require urgent surgery. US can be used in acute small bowel obstruction to determine bowel distension, but is not as accurate as CT in localising the point of obstruction.

Endoscopy, whether by ileoscopy or capsule endoscopy, is obviously the most sensitive test to show early Crohn's disease. However, compression studies in standard barium follow through (BaFT) can also show superficial ulcers, but is difficult to perform in all parts of the small bowel, and it has been suggested that double contrast enteroclysis is the most accurate radiological examination for superficial disease(2)

However, this is technically demanding and not a routine study. The standard small bowel enema may not show early mucosal disease, as it is better at showing early fold deformity than superficial ulcers that may occur without bowel wall distortion and in this respect is inferior to good compression during a BaFT. Long segment advanced Crohn's disease will be readily visible on any examination, but short segment disease and narrow strictures may be missed more easily.

CT and MRI enterography are gaining in usage; particularly as oral techniques have become more successful, obviating the problem of intubation. Both show bowel vascularity, mural and transmural changes, which may help in assessing Crohn's disease activity(3) and especially in diagnosing tumours with an extramural component such as GIST or carcinoid lesions. US with compression yields surprisingly good images of Crohn's disease, but is not as accurate as CT or MRI and has poor localisation.

Adhesions are often ignored in small bowel studies, though these are an important and common problem. These may be suggested on CT, but confirmation often requires moving bowel loops to show that they do not move freely on the mesentery and are adhesed to other loops or the abdominal wall. This is possible only with fluoroscopic palpation and compression.

A well performed BaFT remains a highly accurate examination and still gives the best roadmap of disease. There are some clinical situations, such as obstruction, where CT is the examination of choice. US and MRI have important roles in inflammatory bowel disease as no ionizing radiation is involved.

steve

annalexandria's picture
annalexandria
Posts: 2573
Joined: Oct 2011

they were picked up only by a PET scan. I was first given a test that involved swallowing a little camera. but it got stuck in the area of the tumors and was unable to complete its "mission". CT didn't show anything other than what they called a thickening of the intestinal wall, but the cancer did show up on the PET with pretty high SUVs. I was told that a colonoscopy is not able to get far enough into the small intestine to provide accurate information about what's going on in that area.

pete43lost_at_sea's picture
pete43lost_at_sea
Posts: 3908
Joined: Nov 2010

the odds of getting crc in the small bowel really rare, in the large bowel including rectum well thats an odds on favourite.

the reason is , just my favourite current theory is carcinogens in the stool being in contact for a longer period of time with the bowel wall. and obviously all the common risk factors. being a vegan gets the fastest transit times as long as you are hydrated well. i am for this reason amongst others.

its pretty bleeding edge testing but i imagine our current standard blood test for crc detection is cea. if its evelated then the scans are the way to go.
interresting question.

i hope you are well.

hugs,
pete

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