0:00

So we've good image quality, good protocol.

0:04

Uh, let's get to the task

0:05

of evaluating the coronary arteries.

0:07

I like to start with the right coronary

0:09

artery, just my search pattern.

0:11

I kind of go left to right on the image.

0:12

I also, um, know, uh, as you heard in the lecture,

0:16

that the right coronary arteries, the most likely one

0:18

to have a motion artifact.

0:20

Um, so as I come down here, you see, you know,

0:22

I'm gonna change my fa

0:23

or there goes that sharpened up nicely.

0:25

Um, and another way

0:26

to evaluate the RCA than just axials would be

0:29

to look on a long axis.

0:30

And if I just find the mid ventricle, you know, kind

0:33

of near the acute margin, the rv, I'm gonna center on that.

0:36

Each, uh, pack system in each reconstruction workstation

0:40

works differently, but they all have a common system

0:42

of making an NPR.

0:43

And this is kind of basics.

0:44

There's even free tools you could download if your trainees

0:46

don't wanna practice at home.

0:48

But, uh, the idea would be take your axial image,

0:51

work from there, and then, uh,

0:53

I'm gonna twist this sagittal image here.

0:55

Now it's para sagittal.

0:56

And then I'm also, and try to connect the dots.

0:59

So if you, if you look at here, there's the proximal,

1:01

the distal rca, no RCAs are tortuous

1:03

and they're especially in and outta plane in systole.

1:06

I'm just gonna sharpen this up with a mip,

1:09

maybe add some width to it.

1:10

So things coming, uh, through plane. Uh, now work out.

1:13

So here's the C view like you might see on if

1:16

this patient gets an angiogram.

1:17

So I can look at the long axis. Look for stenosis.

1:21

I'm not seeing anything, but I know

1:22

that a MIP could mask a stenosis.

1:24

So probably think this is, um, on the order of mild,

1:28

maybe moderate and distal RCA.

1:30

Okay, so I've cleared that or at least made a note

1:32

that I, there's some disease.

1:34

So we're at least at above cad, red zero now,

1:37

and the worst stenosis is probably in the distal.

1:39

I think that's probably mild. Now let's go to the left main.

1:43

Left mains are humbling. Left mains are hard.

1:45

If you have only one job, it's to clear the left main

1:48

'cause all the prognostic factors come from there.

1:50

So, um, let's take a look at this left main

1:52

and you can see it's coming through the axial plane.

1:55

Um, and we don't get really one long axis image.

1:58

If you do only one extra view on any case,

2:01

you can read most cases a normal case,

2:03

axials probably gonna do you pretty well.

2:05

Take one look at a long axis view

2:07

because if you have plaque as is in this case

2:10

where it's kind of on the inferior wall of the vessel,

2:14

but not pinching it side to sides,

2:16

you can totally overlook a stenosis.

2:18

And that would be bad

2:20

because people are counting on you

2:21

to be very sensitive and less specific.

2:23

Um, so as your reader, you wanna know that's the,

2:25

the prejudice of the lens

2:27

through which your interpretation will be is

2:29

that CT has a high negative predictive value.

2:31

So if negative, no further workup needed.

2:34

So you don't wanna miss things. Um, you want

2:36

to err on the side of a slight, um, bit of sensitivity.

2:39

So, uh, in looking at this case,

2:41

it doesn't really look terribly narrowed on the left main,

2:43

and that's really the distal left main.

2:45

Um, so I see it now in two views.

2:47

I can angle this to kind

2:48

of bring this into a long axis in my top window.

2:51

I'm gonna change phases just to sharpen things up.

2:53

Just a couple of milliseconds different

2:54

and it's a much better scan.

2:56

We reconstruct a little stack and that's what I've loaded.

2:58

But, uh, especially if you have older technology,

3:00

you may want to just, uh, really wall up the patient

3:02

with beta blocker as if they need it

3:04

and just slow the heart rate down.

3:05

This patient had a slow heart rate so you can then try

3:08

to pick out one phase,

3:09

but for, for us it seems to be, uh, not worth the time

3:13

because we're gonna get a great scan here.

3:14

So we have a fair amount of plaque.

3:16

There's your left main

3:17

and uh, you can look at it in short axis,

3:20

but you don't want to call stenosis, uh,

3:21

grading off a short axis.

3:23

So, uh, I think that's probably mild.

3:26

I don't think we're even approaching 50% here.

3:28

There's your bifurcation. Alright, so I'm gonna follow this.

3:31

So plenty of disease. There may be a trifurcation here,

3:33

there's a tiny ramus.

3:35

Yeah, I'd call that a trifurcation.

3:36

Uh, just probably mild LED remember,

3:39

LED starts at the osteum at the bifurcation

3:42

or trifurcation of the left main.

3:43

And then it's technically the proximal segment

3:46

until the first large septal perforate or a diagonal.

3:49

In this case it's a diagonal right here.

3:51

Um, so this segment here, I'll just put a caliper on it.

3:55

That's your proximal LED.

3:56

And then beyond that, that's your mid LED.

4:00

The definition of a mid LED is till

4:01

that midway down the ventricle.

4:02

So somewhere around here. So I could, uh,

4:05

give you that in long axis.

4:06

And I, I will just for illustrative purposes

4:08

today on this case.

4:09

But, uh, when I, uh, lay out my LAD,

4:15

so again, we know that the proximal stops here

4:17

and now it's the mid, so right about here

4:20

and then about halfway down the ventricle.

4:22

So I'd probably put it about there.

4:23

That's the, the definition of mid to distal.

4:26

So sometimes it's a little ambiguous.

4:27

I often just say mid to distal.

4:28

Important thing is you're guiding the interventional.

4:31

So say I saw a stenosis that I was worried about

4:33

and I thought it might go to the cath lab,

4:36

I should be very clear about

4:37

what I'm talking about and where.

4:38

So if I wanna describe this in my report,

4:41

I would say there's a proximal lesion.

4:43

It's definitely partially calcified.

4:45

There's some, uh, calcified plaque,

4:47

some noncalcified plaque.

4:48

Uh, I think this is just a mild stenosis.

4:50

Uh, if I wanted to call the more here, uh,

4:53

which I'm starting to think this is a little bit

4:55

of a small vessel, then I, uh,

4:57

might say there's a moderate stenosis in

5:00

the, uh, mid segment.

5:02

If I wanna describe something more distally,

5:04

then I'm gonna try to sus that out

5:05

and just be very clear about

5:07

what diagonal branch that I see.

5:08

So here's a diagonal branch.

5:10

So, uh, another good way to look at the vessels

5:13

and assess for tortuosity.

5:14

One of the first statements in my reports

5:16

is are the vessels tortuous?

5:17

We know there are certain diseases that, uh, are associated

5:19

with coronary tortuosity, chronic hypertension,

5:22

arteriopathy like FM fibromuscular dysplasia, FMD or,

5:26

and that can cause spontaneous dissection.

5:28

So just things that are in the back of my mind,

5:30

but a blanket statement about the quality of the image

5:32

as well as, uh, the tortuosity

5:35

of the vessels if present something reasonable to make.

5:37

So here's that large first dag, it's branching.

5:39

Um, and so if I'm trying to sort out a lesion,

5:42

I might use this to say, oh, there's another dag.

5:44

So maybe it's beyond the second

5:46

or third diagonal back to our review here.

5:50

So as we come down the coronaries,

5:53

and we also, um, know in cadre's, uh, guidelines kind

5:56

of specify this, we're not gonna hold ourselves to too high

5:59

of a standard in these smaller vessels.

6:01

So this is 2.5 millimeters that's within real, the realm

6:04

of a coronary ct, but much smaller than that.

6:06

We're not gonna be so accurate.

6:07

There's only a couple pixels, um,

6:09

that would comprise a stenosis.

6:11

So you, you do, um, want high quality images

6:14

and you want to think about giving nitroglycerin

6:17

unless there's a contraindication

6:19

because that makes these small vessels a little bigger.

6:21

About 17% dilatation in the studies we've done,

6:24

we might get another pixel or so,

6:25

but when you're working at the limits, you don't want to,

6:28

uh, overstress it.

6:29

So that was our LADI think.

6:32

I still think this is mild, um, meaning it's not quite 50%,

6:36

but let's just take a look in another long axis view here.

6:39

Uh, we know that calcium blooms, um,

6:42

especially on older CT scanners,

6:43

and this is a fairly modern one,

6:45

but the blooming we get from, uh, the calcium might

6:48

actually accentuate it's caliber fourfold.

6:51

So, uh, if we cut this person open

6:53

and did a pathology specimen, studies have shown

6:55

that the calcium, um,

6:57

about four times thicker on the CT image

6:59

than it is in real life.

7:01

And when you're working in a small vessel, that matters.

7:03

So I, I think I'm gonna err on the side of mild here,

7:05

but I'm a little concerned.

7:06

Um, and then I'm gonna just move over to the circumflex.

7:11

So here's my circumflex coming down,

7:14

and it's a non-dominant circumflex.

7:15

You can see here it's left the AV groove.

7:18

What am I talking about there?

7:19

Well, when I look at a cir, um,

7:21

it's only a circumflex proper when it's

7:24

between the atrium and the ventricle.

7:25

But as soon as it curves away from the AV groove,

7:28

that's the terminal branch.

7:30

And that's the obtuse marginal, its, it was dominant.

7:32

It would continue in the AV groove all the way down

7:34

to the, uh, inferior wall.

7:36

But as units can see in this case the right coronary artery

7:39

supplies, the PDA, which we have there,

7:42

I'm gonna scroll back up, I'm nipping here

7:44

and the PLV comes further over and,

7:47

and, uh, I'll trace that out for a second.

7:49

So the R-C-A-P-D-A, I can't remember we talked about that,

7:52

but losing the vessel here for a moment,

7:54

but I'm just gonna change phases.

7:55

You can see it's, it's all fine.

7:56

It's just that that's an area prone

7:58

to motion, prone to noise.

7:59

'cause you have the diaphragm and the same Z axis level.

8:02

So it's a little disease,

8:03

but um, I don't think that's real significant stenosis.

8:06

So from mild RCA, the circumflex is non-dominant.

8:09

I didn't see much that was very impressive.

8:12

Uh, there is some disease in the diagonals

8:14

and um, there is a little bit of a mild versus moderate

8:19

mid LAD stenosis.

8:22

This person's gonna surgery.

8:23

We want negative predictive value.

8:24

I have a couple of open questions here.

8:26

Um, and then another thing that might be worth, uh,

8:29

a mention is if, if we look at the calcium score,

8:34

uh, which is never enough,

8:36

but uh, we always grab one if we can.

8:38

Um, the calcium score here was

8:43

2,172, so it's pretty high.

8:47

So our pretest risk

8:48

of coronary otosclerosis can be determined

8:50

by clinical factors.

8:52

But once you have a calcium score,

8:53

in fact I'll just show you the

8:54

Calcium image, ton of calcium.

8:58

So, uh, when, when you look at this, you know

9:01

that our accuracy may be, and,

9:02

and we also, another prognostic thing you can get off

9:04

of calcium scores if there's a

9:06

fatty metaplasia in the liver.

9:07

So this is borderline steatosis.

9:09

If, if I do enough calipers, I think so this is somebody,

9:12

yeah, there's a mean less than 35.

9:14

So there's at least regional, uh, hepatic steatosis,

9:17

which in some papers shows it's the same

9:18

as a coronary risk factor.

9:19

And you can see the calcium, you know,

9:21

there's atherosclerosis.

9:22

Um, so with some open questions around the LAD,

9:26

I think this one, um, oughta go for an additional test.