0:00

Okay in this next case, I'm going to

0:03

review a very common artifact that we encounter on

0:06

cardiacct which is motion artifacts simulink

0:09

stenosis or a pseudosynosis from

0:12

motion. And the problem with this artifact is that

0:15

it can be very tricky in show

0:18

up unexpectedly where you have

0:21

a state that looks otherwise a really good in quality.

0:25

And then you have something that looks like a lesion but

0:28

it actually turns out it was a fake out all along and

0:31

so here's this case is a really nice example of that.

0:34

this patient

0:36

as a younger patient at a coronary CT.

0:39

You can see it's a little noisy slightly larger patient, but

0:42

still diagnostic quality.

0:45

You can see the left main here. You can see a sort of small ramus

0:48

branch and then the LED.

0:51

And then when we get out to the LED, here's his origin is

0:54

diagonal Branch with some bridging.

0:57

Just beyond the diagonal branch.

0:59

And I want to focus on this diagonal Branch here. You can

1:02

see right there. It looks like there's a

1:05

stenosis.

1:07

And this is the diagnostic set of images that we were

1:10

working with. So this was like usually when you performed coronary CT

1:13

the scanner is going to give you what it thinks is

1:16

the most motion free set of images the best images to

1:19

use and and this is what it was and and sure enough.

1:22

It looks like there's non calcified plaque causing High

1:25

grades stenosis of the origin of the first diagonal.

1:29

And the other thing just makes it even more doubly tricky

1:32

is that all the other parts of the

1:35

heart look more or less sharp. I

1:38

don't see any obvious blurring.

1:41

That would suggest there's some misregistration.

1:44

If I look in the lung Windows, it looks

1:47

sharp. I don't see respiratory artifacts.

1:50

So this is a really tough one.

1:53

If I only had this set of images I

1:56

would call this a high Grace stenosis at

1:59

the origin. But usually when Corner CT

2:02

is performed in an outer 30 back to our Mastery course

2:05

that we have on the technical aspects of coronary CT. Usually we

2:08

perform coronary CT with multiple phases.

2:12

And part of the reason that's really helpful is because oftentimes

2:15

we have things like this.

2:18

So how do you know this is an artifact and you really don't?

2:22

The only thing you know is that you maybe are suspicious because

2:25

this patient has otherwise would look like really clean coronaries.

2:30

So when I see clean corn areas and just one isolated lesion,

2:33

I'm gonna get a little bit suspicious and I

2:36

feel a lot more comfortable confirming that this lesion is a real

2:39

stenosis on some other

2:42

Phase of the examination so this was performed at the 75%

2:45

reconstruction phase.

2:47

And this image over here was actually performed at 65% reconstruction

2:50

phase. So both late diastole both

2:53

generally good images for getting good quality evaluation in

2:56

the coronaries at a low heart rate. But you

2:59

see here that this area of the origin

3:02

of the diagonal is completely wide

3:05

open on this 65% phase and you

3:08

know contrast that to this occluded looking

3:11

diagonal origin on the 75% phase. So just that

3:14

little change in the portion of

3:17

the cardiac cycle that we're Imaging made a huge difference in terms of visualization of

3:20

this coronary. So I show this as a kind

3:23

of a word of caution

3:25

When you have the multi-phase data, you should definitely use it to make

3:28

sure that if you're calling any severe stenosis that

3:31

that's stenosis persists throughout all the different phases.

3:35

And especially when you're talking about somebody who has very limited or

3:38

minimal disease or no disease elsewhere. You want to

3:41

make sure that you're not over calling something because of what ends

3:44

up being a fake out.