So this lecture is going to cover GI fluoroscopy, we'll go over some of the basics of fluoroscopy
including the different types of studies that can be performed as well as exactly what fluoroscopy is and what its uses are.
So, fluoroscopy is the use of x-rays in real time to perform a dynamic evaluation of the area that's being studied,
it's different than the rest of radiology because it is more of a dynamic evaluation.
Radiopaque contrast material in liquid form is given to the patient to drink
or it's injected rectally or through a feeding tube in order to study the GI tract.
Real-time video and static images are then obtained in various different patient positions
as the patient drinks and so in this way, we get a more dynamic evaluation.
Besides this usage fluroscopy can also be used in a number of other procedures.
for example in vascular procedures or if you want to perform a TEVAR.
So, what is the difference between single versus double contrast imaging?
Single contrast imaging uses only a contrast agent to fill the lumen of the bowel
and it's used mostly to see filling defects within the bowel lumen.
However, double contrast imaging uses both air and a contrast agent and it's used to distend the bowel
and also coat the wall, so this is used more to see mucosal abnormalities of the wall.
The different types of contrast agents include barium sulfate which is not water soluble or Gastrografin, Isovue, or cystografin,
all are used essentially for a similar purpose and those are water soluble.
Barium sulfate comes in different consistencies while Gastrografin, Isovue, and cystografin, the water soluble contrasts, only come in liquid form.
And barium sulfate is the most commonly used agent for both single and double contrast studies.
The water soluble agents are really used for GI studies where a bowel perforation is suspected, they can also be used for GU studies,
so these are agents that are used more in times where if there's a bowel perforation and the contrast perforates into the peritoneal cavity,
it's absorbed more easily while barium sulfate is not.
So, what are some common GI fluoroscopic exams? We can do a barium swallow which is also called an esophagogram.
We can do an upper GI series which includes a barium swallow as well as evaluation of the stomach.
We can do a small bowel follow-through which often goes along with an upper GI series,
so we take a look at the esophagus, the stomach, as well as the entire small bowel.
We can perform a tube study which is done by injecting contrast into a G-tube for example that the patient may have.
We can also do a barium enema which is injecting contrast rectally to take a look at the colon.
So, let's look at some examples of a barium swallow.
This can be performed as both a single or a double contrast study.
It's used to evaluate intra-luminal esophageal abnormalities or it can also be used to evaluate esophageal motility,
again because this is a dynamic examination.
It can also be used to detect an esophageal rupture.
Modified barium swallows are performed in conjunction with a speech pathologist to evaluate for risk of aspiration.
So, what this entails is a radiologist and a speech pathologist working together.
The radiologist takes multiple images while the speech pathologist gives material of different consistency to the patient.
So, it's different consistencies of barium.
It can be liquid barium, it can be semi-liquid barium, or it can be solid barium,
and we watch as the patient swallows to see if they are having any swallowing difficulties with the different consistencies of barium.
So this is an example of a barium swallow.
The left image is a double contrast image which shows you the coating of the wall,
and this is the one that's used for mucosal abnormalities.
On the right, we see a single contrast exam.
So we can see that the entire lumen of the esophagus is filled with contrast
and this is really to look more for intra-luminal abnormalities.
This is an example of normal esophageal peristalsis that is seen on a single contrast examination.
So, the esophagus is of equal caliber all throughout,
but when you see a fold like this that comes and goes, this is an example of esophageal peristalsis.
So, what do you see on this single contrast barium swallow?
This is the patient that presented with difficulty swallowing.
So, when you compare this with the previous one,
we can see that there is a smoothly marginated esophageal mass that results in narrowing of the esophagus.
This is different than the normal esophageal peristalsis
because we can see acute margins here on each end and we can see that there is compression really just from one side.
The other side of the esophagus actually looks normal,
while in esophageal peristalsis it's both sides of the esophageal wall that peristals,
and so you can see an area of constriction that covers both sides.
So, this is an example of esophageal carcinoma.
These are two CT images from the chest that show the same mass right here that is compressing the esophagus.
Esophageal diverticula are also seen on a barium swallow.
This is a defect in the muscular wall of the esophagus that results in the mucosal and submucosal layers herniating through it.
It appears as an outpouching of contrast from the lumen.
An example is Zenker's diverticulum.
Zenker's diverticulum is a diverticulum of the esophagus.
It's often associated with esophageal dysmotility.
So when you have frequent esophageal dysmotility and the esophagus does not peristal in that region,
fluid and food tend to accumulate within one portion of the esophagus and it causes an outpouching or diverticulum.
And, this is an example of a hiatal hernia which can also be seen on a barium swallow.
You can see multiple gastric folds extending through the diaphragmatic hiatus.
The gastric folds really should remain below the diaphragm, and if you see any folds extending above,
then that's an example of a hiatal hernia.
So, what is an upper GI series? It is a fluoroscopic evaluation of the esophagus, stomach and duodenum.
The most common abnormalities found on an upper GI series are gastric or duodenal ulcers and gastric carcinoma.
This is an example of normal images of the stomach.
So, you can see the normal stomach folds on this double contrast upper GI series.
This is normal to see. You can see areas that fill with contrast and we change patient position
to make sure that all of the areas that fill with contrast actually empty at some point.
So, here you can see that in the stomach, we have a lot of contrast that's staying up in this area,
but when we change the patient's position, all of that emptied out.
So, we wanna make sure that all of the mucosa is visible when we do an upper GI series. So, what is a gastric ulcer exactly.
It's an outpouching of contrast that's due to a break in the mucosal lining.
It's differentiated from a diverticulum because the diverticulum actually has intact mucosa,
and a gastric ulcer is seen well on double contrast fluoroscopic examination of the stomach.
Gastric and duodenal ulcers can both present when we do an upper GI series.
So, what's the difference? A duodenal ulcer is most related to Helicobacter pylori infection and it's less commonly due to NSAIDS.
Gastric ulcers are most related to H. pylori infection as well and not really as common because of NSAIDS.
Duodenal ulcers are more common in general than gastric ulcers are.
Duodenal ulcers are usually located along the anterior wall of the duodenal bulb while gastric ulcers
are most commonly located along the lesser curvature or the posterior wall of the body or antrum, and duodenal ulcers are most commonly benign.
Gastric ulcers are also most commonly benign but less than 5% may be due to gastric malignancy.
So, this needs to be further worked up usually with an endoscopy if a patient is shown to have a gastric ulcer.
So, let's take a look at this case.
This is a single image of the stomach from an upper GI series.
Do you see an abnormality on this image?
So, we see here a single outpouching of contrast arising from the stomach.
This represents a gastric ulcer.
So, this is a finding that you wanna make sure that you don't miss when you're performing an upper GI series.
This patient will need endoscopy to take a further look at the gastric ulcer and make sure that it's not resulting from a malignancy.
So, what can a gastric mass represent?
A gastric mass can be a carcinoma; it can be a leiomyoma.
It could represent a lymphoma, or it could be a bezoar.
So, let's take a look at this patient.
This is a single contrast image of the stomach, and what do you see on this image?
So, this patient has a polypoid filling defect within the gastric antrum and this represents a gastric adenocarcinoma.
Again, looking at this one image, we don't know exactly what it represents.
It could be any one of those masses that we described
and the patient would need an endoscopy with biopsy to take a better look at what's going on.