So, small bowel follow-through is a single contrast fluoroscopic evaluation
of the small bowel. It distends the bowel
to allow evaluation of intra-luminal filling defects, fistulas,
lack of bowel movement due to adhesions, and narrowing of the lumen.
Contrast is followed from the stomach until it reaches the cecum
and then multiple images including those
with manual abdominal compression are obtained,
so once the contrast reaches the terminal ileum and enters the large bowel,
we actually go in, we manually compress with our hand
and take multiple images with compression
so that we can see what the small bowel loops look like.
So this is an example of a normal small bowel follow-through,
you can see contrast within the stomach
and then you can see contrast extending throughout the small bowel.
We wanna make sure that the entire small bowel is opacified
before we stop the examination
and this usually takes about one and a half to two hours.
This is an example of a patient with Crohn’s disease.
Crohn’s disease causes multiple strictures throughout the small bowel
and this patient has narrowing of the terminal ileum which is shown right here.
You can see that the terminal ileum is actually very narrow
and you can see on these two images that there are multiple fistulas
extending through multiple loops of small bowel,
so we have a loop of small bowel here which looks relatively normal,
we have another loop of small bowel here
and then we have multiple fistulas that extend between the two
and this is also a common finding seen with Crohn’s disease.
A tube study involves injection of water soluble contrast through a feeding tube
to ensure that the tube is in satisfactory position,
it does not demonstrate a leak. So this can be done with really
any kind of tube that the patient has, it could be a J-tube,
it could be a G-tube, and water soluble contrast is injected in.
This is an example of a gastric or G-tube study.
Contrast is injected into the gastric tube
and it demonstrates that the contrast stays within the stomach,
this indicates that the tube is in satisfactory position and can be used.
This is another example, so we see initial images that were obtained
when contrast was first injected and then after a few minutes,
you can see that the contrast is passing through the stomach
and into the small bowel which is the normal finding
and this is something that you wanna make sure happens
to make sure that the tube is in good position
and that stomach motility is normal.
So, a barium enema is performed when contrast is injected rectally
and can be performed as a single or a double contrast evaluation
of the large bowel. Air is injected along with barium
for a double contrast evaluation.
Usually, this is performed in patients who cannot tolerate a colonoscopy,
it’s used very infrequently because this also involves a lot of patient discomfort,
and there’s actually relatively low sensitivity in finding a mass
with a barium enema. CT colonography is actually a better alternative
to patients who can’t tolerate a colonoscopy.
So, CT colonography is actually a CT scan of the abdomen and pelvis,
it’s performed after the colon is distended with air
that’s injected through a rectal tube.
This is an example of a CT colonography,
so you can see multiple air-filled loops of large bowel
and this is performed after insufflation of air into the colon via a rectal tube.
You can see multiple air-fluid levels
and this is normal in a CT colonography because air is injected into the colon,
this is not a normal physiologic finding, it’s because of the insufflation of air.
And you can see on this coronal image,
a rectal tube in place which is kept in place and air is injected through this.
So, what do you see on these images?
On the left we have an axial CT image of the pelvis
and on the right we have an image from a barium enema.
You can see multiple loops of the small bowel here filled with contrast,
we have small pockets of air within the small bowel,
and then we have this loop of what looks like large bowel.
Do you see an abnormality with the large bowel?
So this is an example of colonic diverticulosis.
We have multiple small, round outpouchings of colon
which are filled with air and contrast, you can see a couple of them here
as I point them out, you see one right here.
So this patient has multiple diverticuli.
Mostly, these patients are asymptomatic but they can cause GI bleeding
and if they become infected or inflamed, it can result in wall thickening
and surrounding inflammatory change
which can eventually perforate and cause abscess formation.
So if these are inflamed, then the patient needs to be on antibiotics
to stop the inflammation. Colonic polyps are mostly hyperplastic,
they don’t usually have a malignant potential.
There are multiple different types of polyps
and the adenomatous polyps have approximately a 10% chance
of malignancy once they’re 1.5 centimeters in size.
So these are usually diagnosed either on colonoscopy or on barium enema,
and then if they are seen on barium enema,
these also need to be sampled via colonoscopy.
What do you see on this image?
This is an example of a barium enema and this is a portion of the colon
that we’re looking at. This is actually an example of a colon cancer,
it could present as a filling defect on fluoroscopic imaging
or it could present the way this is presenting
as an annular constricting lesion which is also called an “apple-core” lesion.
You can see here the resemblance to a normal “apple-core”.
So this is the classic appearance of colon cancer as an “apple-core” lesion.
So, we’ve gone over multiple different fluoroscopic exams and their uses.
Fluoroscopy is different than the rest of radiology because it is dynamic
while the most of the rest of radiology is static,
so this allows real-time evaluation of any abnormality that may be going on.