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Leaflet Thrombosis (HALT) Case Review

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In this case,

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we're gonna review a case of hypo attenuating leaflet thrombosis after

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TAVR or halt and just talk about some of the typical imaging findings.

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So I'm gonna start with the axial slices here. And as you scroll first,

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you're gonna see that this patient for sure has a TAVR device, right?

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You can see the struts. And then as you head down inferiorly,

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you can see the leaflets on this TAVR device.

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And you can see this really low attenuation stuffed, which is,

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um, sitting in the expected location of the leaflets.

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So that's your hypo attenuated leaflet thickening. Now on the axial images,

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it's kind of hard to tell exactly how much thickening there is,

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so we're certainly gonna rely on the multiplanar images for better definition

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of what's going on. So as before,

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it's really best to start with these cornal images. And

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what you can do is you can reorient your plane so that you're aligned with

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parallel to the aortic valve.

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This is gonna give you another long axis image here

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and your short axis image here.

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So what you do is you first can assess the extent of

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le thickening with the long axis images. So in this case, you know,

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it's zero to 25, 25 to 50. You know,

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we go by quartiles and in this case I'd say

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it's at least around 75% of this leaflet is occupied by thrombus.

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And so you can go through that leaflet by leaflet.

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In this case we were looking at,

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it looks like this is the right coronary cusp here.

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That's this leaflet posteriorly. That one doesn't look quite as bad.

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Actually, I take that back. There's still a fair bit of, uh, thrombus. So, um,

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similarly, somewhere in that 75% range. There you go.

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And then opposite to that, if you look and cross correlate,

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it looks like we're looking actually at the left coronary cusp here,

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based on the location of this pink line here, which defines this plane.

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So that's about 75% as well. And then if we're looking at the, um,

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additional purple plane, which is the non coronary cusp, uh, you know,

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maybe that's a little more like 50% that you can see. Uh,

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actually I take that back. I think it's probably still about about 75% or so.

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So that's how much of the leaflet's involved by the halts.

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And then the next question is, what about the restriction of motion?

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So right now we're in the diastolic phase,

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so you want to get yourself into the systolic phase.

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So I'm gonna hit the play button and we're gonna just first watch what happens

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and as we're going through the cardiac cycle,

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and you can see you definitely get a lot of artifact as

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the device is moving through the cardiac site hold because of

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Just motion related blur.

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See if we center ourselves on the device, again, centered on it,

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now we can look at all the different planes and try to figure out what's maximal

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point of opening. And, uh, systole, um, in this case,

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you wanna look for the spot where the, uh,

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ventricles really squeezed down tight and the leaflets seem

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to open up to the greatest degree. So we're heading into assistly.

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Um, now right about there

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maximal leaflet opening. It's gonna be right around these phases here.

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So I scroll downwards through, uh, images here in the bottom,

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uh, right hand corner.

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I can just page through the different phases and see where I find

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the maximum degree of opening. So in this case, we're,

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um, you can't see the numbers, but we're about 30% phase.

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And then now we're moving backwards in the cardiac cycle.

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And now we're at around the 25% phase.

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And that's actually around the 20% phase,

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which we know is usually around peak system.

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And I think this is where we see a good degree of leaflet opening.

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And I'll just check, uh, 15 to see if that's any different.

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Looks pretty similar. And same with 10 as well.

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So I think any of those phases really is probably gonna be, um, safe to use.

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We've got a fair bit of motion related artifact on this 10% phase.

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So I'm gonna skip ahead to 20 and then we can measure the

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relative leaflet opening. Um, we'll just do it for one leaflet.

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And the way you do that is you select your distance measurement tool.

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You find where you see the most distortion of the leaflet from the

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thrombus.

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You measure the maximal distance across the valve of that

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level. That's 21. You divide that by two.

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So 10 and a half you do a secondary measurement from the

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tip of that leaflet filled with the thrombus to the wall, you get six.

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And so then our degree of leaflet restriction is going to be

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six over 10 and a half, or you know, six over 10, which is roughly 60%.

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So that would fall into the, the moderate range.

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So that's your roughly your approach to evaluating patients for hypo attenuating

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leaflet that can.

Report

Faculty

Stefan Loy Zimmerman, MD

Associate Professor of Radiology and Radiological Science

Johns Hopkins Medicine Department of Radiology and Radiological Science

Tags

Vascular

Idiopathic

Congenital

Cardiac valves

Cardiac CT (SCCT Cat B1 Video Case)

Cardiac

CTA

CT

Acquired/Developmental