0:00

So why might you want to do delayed imaging as part

0:03

of a, a coronary ct?

0:05

Uh, well it's been shown in some studies.

0:07

Uh, here's one that our group looked at, uh, that the

0:11

addition of multiple phases can help your specificity.

0:14

So this is a CT p CT perfusion exam,

0:18

and you can see this is a heavily diseased patient, somebody

0:20

with known, uh, coronary artery disease.

0:23

And you can see the calcium makes the coronary

0:25

CT very hard to read.

0:26

So this is the LAD,

0:28

but I'm also showing you here's a profusion

0:30

defect in the first pass.

0:31

And so you have hypo enhancement

0:33

and that correlates in the circumflex

0:35

to the circumflex occlusion that you can very clearly see

0:38

by the invasive angiogram

0:39

and is hard to sort out in the, uh, CT angiogram.

0:42

There's lots of calcium, it's also visible.

0:44

Um, but you see here a circumflex perfusion defect

0:48

and you see that the RCA while disease

0:50

and very hard to look through on A CTA is patent

0:53

by angiography.

0:55

Conversely, if you add a delayed image,

0:56

you can sort out what's not just hypoperfusion

0:59

during stress, but or at first pass,

1:01

but actually an infarct.

1:02

So here's another case. This is a patient

1:04

with a longstanding LAD occlusion

1:07

and I'm showing you matched MRI and CT images.

1:10

And you can see a transmural infarction

1:12

by late gadolinium enhancement.

1:14

You can also see that same thing by ct.

1:16

So whether you use a CT

1:18

or an MRI, you are looking at small molecules getting

1:21

into that fibrous scar.

1:22

So there's a complete transmural infarct of the apex here.

1:25

Um, and so you can look at a

1:27

CT protocol to be comprehensive.

1:28

You can use different modes,

1:29

but basically by getting a non-contrast, a contrast

1:33

and delayed images that might help you, uh, sort out the,

1:37

uh, presence of an infarct.

1:38

And you can do that with either modality.

1:41

So in, in summary, you can actually, from a coronary ct,

1:44

you get the anatomy looking at the coronary arteries,

1:46

you can look at relative profusion defects.

1:48

Here's a patient with a diagonal occlusion.

1:51

It was acute, so this is first pass.

1:53

You can look at the myocardial function, uh,

1:55

which we are gonna often get while just acquiring

1:57

your coronary ct.

1:59

Um, and you can also get a late image

2:01

and look at, uh, infarct.

2:02

Now the first line is usually gonna be an MRI

2:04

to look at late enhancement,

2:05

but a CT can certainly do it if it's needed.

2:07

And sometimes you get it whether you are,

2:09

uh, looking for it or not.

2:10

If you especially, uh, doing a coronary CT combined with,

2:14

say, in a chest CT

2:15

or an abdominal ct, you might be acquiring late phases.

2:18

So those are the kind of, uh, basic parameters

2:21

with which you can sort out ischemic coronary disease.

2:24

Uh.