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Multiphase Imaging (Retrospective Gating)

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So I'm going to show you a case of multi-phase imaging,

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and we'll talk a little bit about the acquisition

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and also the point of the acquisition method.

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So this was obtained retrospectively gated.

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It's low pitch, somewhere around 0.25.

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7 00:00:29,540 --> 00:00:36,910 And the purpose was to assess aortic valve motion.

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And therefore, we wanted to get the aortic

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valve, aortic annulus, which is this plane here.

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We ended up getting a little bit of a ventricle.

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So the first thing is that you can work this out

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like a standard sequence and play around with it

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until you get the cardiac planes that you want.

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And I'm just going to demonstrate

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the short axis plane here.

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And the other thing you can do

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is you can play a cine loop.

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And that's what I'm doing over here.

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And so I can look at wall motion, I

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can look for function, wall thinning,

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and aneurysms and stuff like that.

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So this, in particular, this study was acquired

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retrospectively, and for all positions of the heart,

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such as this position here, we have information

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throughout the cardiac cycle, and we reconstruct

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at certain intervals, such as 5% or 10%.

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Here we are reconstructing at 5%

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intervals, and so, like this anterior wall

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here, we have information in all the phases.

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This is how we used to do all our coronaries in

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the past, because we were worried that we didn't

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get the right data, that we might need another

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phase to look at another portion of the heart.

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That's now being supplanted by various forms

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of what almost approaches perspective imaging.

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And instead, we use this when we need multi

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phase data, such as of the valve here.

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So this is a nice three-dimensional

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cross-sectional view of the valve.

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And we can now look at the valve.

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Here it is systole.

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The valve opens, but may not open

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as much as we would want it to open.

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Stenosis.

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And here is diastole.

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And in diastole, the valve is closed.

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And you can see that there is nice closure.

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There is good acquisition.

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So this particular study was done as a planning

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for pre-TAVR, which is a way of placing a valve

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endovascularly, a very popular method at the moment.

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We end up choosing the best phase that shows us

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the annulus with the least amount of motion so that

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we can select that for our measurement purposes.

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Thank you.

Report

Faculty

Saurabh Jha, MD

Co-Program Director, Cardiothoracic Imaging Fellowship, Associate Professor of Radiology

University of Pennsylvania

Tags

Vascular

Coronary arteries

Cardiac CT (Category B1 Video Case)

Cardiac

CTA

CT

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