Interactive Transcript
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All right, so for our last case today, we're going
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to try to put together an approach and a report for a
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more complex disease in a patient with Crohn's here.
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And so again, as always, the first step is to
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look at our key sequences for detecting disease.
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So I'm going to start with this
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coronal post-contrast series.
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And right away in the pelvis, we see several
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loops of bowel that are clearly enhancing
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more than the adjacent similar loops.
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These end up being ileal loops.
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Of course, you can see it connecting
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here with the cecum in the right abdomen.
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So there's a lot of inflammation
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involving these ileal loops.
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That's clearly evident with this enhancement
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pattern, where you see that inner wall enhancement
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and some suggestion of wall thickening.
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We're also going to try to see if there are any skip
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lesions or other lesions in the more proximal bowel.
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And to me, this proximal bowel looks
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to be enhancing similarly throughout.
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Also, the colon doesn't look like it has a
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lot of abnormal enhancement in this region.
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You see some stool in the colon, but you
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don't see a lot of hyperenhancement.
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So, so far, it's really the ileal disease
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that's most prominent, with potentially a little
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bit of enhancement of the ascending colon,
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which may indicate some mild disease there,
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and the remaining bowel looks pretty normal.
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So, looking at our T2 sequence, we again
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see a similar appearance of the distal ileum
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here with some clear wall thickening.
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You can see some haziness in the
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fat, which is an important finding.
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It indicates a more severe disease process here.
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As far as the remaining bowel, it looks
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like fairly normal fold-type patterns
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here in the jejunum and the colon,
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it doesn't show any severe wall
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thickening that we can see.
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Looking in the axial plane to help us identify
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more diseased segments, we again see that
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the more proximal bowel looks pretty normal.
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The colon, again, is filled with
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stool, but otherwise appears normal,
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with the exception of, I think, a little bit
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of mild inflammation of that ascending colon.
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So very mild enhancement without other findings.
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And lastly, looking at diffusion, our other
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key detection sequence, I believe we see a
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lot of diffusion abnormality in the pelvis.
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And in the remaining bowel, we don't see
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a lot of diffusion signal abnormality.
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We do see some scattered lymph nodes,
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which don't look especially enlarged,
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but maybe some reactive lymph nodes.
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And then that ascending colon doesn't look
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like it has a lot of inflammation here.
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So if there's any disease in
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the ascending colon, it's really quite mild.
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So our primary focus is going to be
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this diseased bowel in the pelvis.
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For our next step, we want to
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characterize that a little more fully.
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In this case, where there's so much disease, getting
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precise measurements of the length of disease
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involvement isn't going to be feasible, particularly.
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So just giving a ballpark estimate, saying
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there's maybe 30 to 40 centimeters of disease
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involvement, is generally how I approach this.
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Okay.
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Next, we want to see if it's acute or
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chronic, and there's clearly a large
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component of acute inflammation here.
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In addition to the, you know, marked hyperemia
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early, it does look like there's edema in
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the wall, causing that wall thickening.
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When we look at our fat-saturated sequence, it does
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look like those loops of bowel are brighter
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than similar appearing loops of bowel elsewhere
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and brighter than the adjacent skeletal muscle.
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So there's a large acute
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component to this disease process.
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Additionally, we've got this enhancement
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that goes outside of the wall.
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And so that, first of all, indicates there's
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a pretty significant acute component with this
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enhancement and abnormal T2 signal that we're
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seeing outside the wall of the bowel in that region.
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And it also indicates that we need to look really
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closely for any strictures or fistulizing disease.
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When we look at this sequence, it does look
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like we have that kind of asterisk look.
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So it does look like
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we're going to have a complex
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fistulizing disease here.
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And this is connecting all these loops of
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diseased small bowel in the lower abdomen there.
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So I would characterize this as a complex fistula
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with multiple tracts, connecting loops of small bowel.
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That can be confirmed on not just that sequence, but on
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other projections showing that similar asterisk shape.
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And of course, when there's a fistula,
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we need to look for abscess.
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So we do see some free fluid down here,
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but this doesn't have a wall around it.
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So it looks like it's just simple
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layering free fluid on this T2 sequence.
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We're not going to pick up
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that fluid very well here, but...
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What we can see on our post-contrast
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sequence is any pockets of enhancement
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that aren't directly connected to bowel.
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And here we see that there's
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maybe a little pocket here.
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You can see these loops of bowel and these tracts
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connecting these loops of bowel all throughout here.
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But this does not have an associated loop of bowel.
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It's an isolated pocket in the mesentery
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of the small bowel in that region.
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So that's concerning that
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there may be an abscess there.
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So how do we confirm that?
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Well, let's look at our other sequences.
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And when we look at this diffusion sequence,
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we see right where that area is, where
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there's that pocket, is very restricting.
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And that often happens when you have a lot of pus
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or a lot of infected cells that are tight together.
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They show some diffusion restriction.
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So this is confirmatory evidence that there's a very
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small abscess associated with this complex fistula.
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When we look at our other sequences that
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further confirm that we kind of have
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this hazy T2 look at the site where that
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suspected abscess is outside the bowel wall.
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We're going to characterize that as an abscess.
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We're going to want to give a
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size measurement for that abscess.
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It's not huge, it's only one and a
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half centimeters, but it is real.
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And so we want to include that in our report.
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So in the end, our final impression is going
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to include the diseased segment, which is
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predominantly the distal ileum with possible
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mild involvement of the ascending colon.
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It's going to say that there's 30 to 40
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centimeters of distal ileal involvement.
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There's associated fistulization
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and active inflammation
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of the loops of bowel.
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And there's a small one and a half centimeter abscess.
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So those are going to be the key components
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that we want to put in our impression.
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Hopefully, that helps you as far as how to take an
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approach that's reasonable to these more complex
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cases that can take a lot of time and energy
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to really figure out exactly what's going on.
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