Pitfalls: Question and Discussion (2)

Evolution in Approach to Oral Contrast

The question, briefly summarized is has there been an evolution in your approach to the use of oral contrast?

Very much so.

When we suspect primary bowel pathology, we almost always prefer to have a neutral contrast agent rather than a positive contrast agent.

It's really critical when it comes to the setting of bowel ischemia.

And I think I've shown you many examples of other settings in which it would be useful.

Crohn's disease, for instance.

Jen and I may or may not have a point of disagreement on that.

Voluma vs. Water as Neutral Agents

Her colleagues at NYU have been among the leaders in popularizing and testing out the Voluma product.

I don't remember the generic name for that, but the Voluma definitely works better for descending the more distal small bowel, because it's not absorbed very well from the gut for the proximal bowel stomach duo and proximal jejunum.

In my opinion, water works just fine.

So I don't have anything against volin, but we don't use a tremendous volume of it except for specifically for CT enterography.

So mostly we're using water.

The only thing I would add to that is that it is true that in the outpatient setting, if somebody presents with sort of more chronic abdominal pain symptoms and there's a question of a primary bowel abnormality, it's true that that patient is likely to be prescribed to get volin.

Emergency Room Settings and Acute Appendicitis

But we still do in the emergency room setting, and somebody comes in with more acute symptoms and you're concerned about something like acute appendicitis.

I think personally, I have diagnosed a couple of cases of acute appendicitis that were initially unsuspected in our outpatients.

And I think it's really tricky on Voluma with a neutral enteric contrast.

I think it makes it a lot more difficult to identify that fluid filled perhaps mildly inflamed appendix.

So we still are in the ER setting, still giving positive enteric contrast.

Challenges with ER Physicians and Timing

And then what I usually get when I speak at meetings like this is at least somebody can't wait to tell me, but my er docs will not let me give oral contrast because they want a diagnosis in 30 seconds as opposed to waiting for the contrast to percolate through.

I agree. For appendicitis, would I rather have positive contrast on board? Yeah, I would.

But I would say overall our ER docs are a pain in the butt when it comes to waiting 30 minutes or something.

So we tend to not give positive contrast in that setting.

Oral Contrast in Oncology Patients

I would say the biggest group that we still knowingly give positive contrast to is the oncology patients.

I mean, that's still a big part of our workload, but for the acutely ill patients, we're using water or voluma very commonly, most often water.

Thanks. Other questions? Yes.

Ruling Out Abscesses

For the abscess, try to rule out abscess.

Try to do what? I'm sorry.

Try to do out access rule out abscess.

Oh, for rule out abscess. Yeah, I'm sorry.

It certainly can be valuable in some cases where presumably an abscess, particularly if it had some kind of peculiar shape, might be misinterpreted as pacified bowel.

Advances in CT Technology Reducing Reliance on Positive Contrast

I think what one of the reasons we have moved away from relying on the positive contrast is as the CT scanners have gotten better, as we're able to get more uniform opacification of vessels in bowel wall by rapid scanning and rapid bolus infusion of contrast with the addition of multiplanar reformations, I think we just feel less dependent on it for most purposes.

Application to Diverticulitis

I know that at various times some of my colleagues have said, oh, boy, I'd really like to have a contrast in the colon when we're thinking about diverticulitis.

But I don't know.

I mean, I've seen hundreds of cases of diverticulitis, many of them with pericolonic abscesses, and I don't remember too many cases where I really felt ill at ease in recognizing the abscess without enteric contrast.

But I certainly wouldn't criticize somebody for giving it.

Jen, what do you think?

Routine Abdominal Pelvic Protocol and Jen's Perspective

Yeah, I mean, I think that was sort of fall into our sort of routine abdominal pelvic protocol where we still would, unless there's a specific reason that they don't want to delay the scan, we would still give positive enteric contrast in that setting most likely.

But sometimes, if the patient's very ill or they can't tolerate the po, we'll certainly go ahead and do it without any oral contrast.

And I would agree with Dr. Federally that most times you don't in fact need it.

I think you're in a more difficult situation if you can't give IV or oral contrast.

Yeah. Then it becomes a little bit more tricky and perhaps is a little bit more essential in that setting.

But if the patient can tolerate the iv, I think if you're looking for an abscess, probably, we prefer to give it, but we do not require it. Let's put it that way.

Med Student Education on Bowel Obstruction Protocols

You know, essentially I'm in charge of med student education at our place, and I'm running one of my courses right now, but I talk to the med students about oral and IV contrast and so forth, and I was asking them just, I think it was yesterday, in fact, if you were worried about a bowel obstruction and you were ordering a CT scan, how do you think you would order it?

Not that you should be setting the protocol, and they'd say, well, oral contrast would be really essential, but we don't have to go iv.

And it in fact, it's just the opposite.

The IV contrast is really important because you really want to pick up those cases of the closed loop obstruction and ischemia and so forth.

And the oral contrast, first of all, the patient's probably not gonna drink it, it's probably not gonna get down to the point of obstruction, but you don't really need it because you've got the intrinsic contrast of the fluid in the bowel upstream from the obstruction.

So we're actually very fortunate in a situation, most of the cases where, in my opinion, you really don't want to have positive contrast.

The patients are not really real inclined to be drinking a lot of positive contrast anyway because it's the acute condition, the patients with ischemia or an active inflammatory process and so forth.

So in a way, we're lucky in that way.

But keep pressing for the iv contrast.

Emergency Department Orders for Rule Out Renal Stone

A comment I get from registrants frequently is every order for an abdominal pelvic CT scan out of the emergency department in my hospital comes as a rule out renal stone because they figure they're gaming the system, right?

It will, they know we'll do the scan immediately with no oral, no IV contrast.

You really want to talk them out of that because that is really hampering our ability to diagnose so many different things.

The absence of IV contrast in particular.