0:00

Perfect.

0:02

Good evening. Uh, it's meet dr.

0:04

We're gonna finish the rest of the course for next couple of

0:08

five weeks together, going over these cases.

0:11

So what I usually like to do

0:13

during this office hours is really just ask questions

0:16

and answers and kind of go through the cases

0:20

that you guys want me to go in more detail.

0:22

Obviously, I can go through each one

0:24

of the cases individually and give you my summary,

0:27

but you have access to the case report, case discussion,

0:31

you have access to the answer.

0:32

You submitted your report,

0:34

you've had your feedback for the grading.

0:36

So I find that it's often more, more helpful if we kind

0:39

of ask questions that you have.

0:42

I pull up the case, I share my screen,

0:44

and then we can kind of go over tips and tricks of that.

0:46

If, if you don't mind now,

0:48

if you don't wanna have a full on conversation,

0:50

you can always ask your questions into the chat

0:52

and I can reply to those as I can see the chat box

0:54

or we can, you know, go as as you need to.

0:59

But I'm, I'm here for you for the next hour

1:02

and I'm here to kinda help answer any questions,

1:05

any concerns you may have.

1:06

So do you guys have any questions in particular

1:09

or anything about the cases?

1:11

Uh, they were the, probably some

1:13

of the most challenging cases you'll have in the course.

1:16

I think they get haver ones are definitely the most complex

1:18

ones, but these are second most complex if,

1:21

if I could say so.

1:23

So, any questions, any, any concerns, anything of that sort?

1:29

No.

1:34

Okay. Yeah, through question five.

1:40

Okay. Let me see page five, case number five. Okay.

1:45

Coronary sinus. Yes, let's do that. Let's pull that up.

1:49

So I'm gonna share my screen and go from there.

1:55

And here

2:00

you can have this kind of coming up.

2:02

This is a very, uh, interesting case.

2:05

Uh, we kind of put this one to kind of try

2:08

to help understand some of the, um, injection findings

2:12

that we were seeing on the, on the ct,

2:15

and more importantly, some of the other, um,

2:19

findings we were seeing anatomically

2:21

that were part of the case.

2:23

So let's go through case number five,

2:26

and I think this was a, a, a very interesting case.

2:29

Uh, just given the, the overall history.

2:32

You know, we have the case 57 50, this is a clinical case.

2:35

She's a 58-year-old female who has diabetes, hyperlipidemia,

2:39

early coronary disease,

2:41

and she's experienced symptoms with shortness of breath

2:44

and early coronary artery disease.

2:47

So obviously CT is one of those first coronary findings

2:51

that, that you want to, to assess

2:54

and rule out when, when we start and,

2:56

and we're try to instill that first approach.

2:58

So, so let me just kind of go over how I like

3:02

to approach my my cases.

3:05

Usually one of the things that you want to do first

3:08

is I like to usually increase my mip, not quite, uh, as, as,

3:13

as high as like, you know, five 10 mil mips,

3:17

you know, the slab thickness.

3:18

You can adjust on tear recon and you right click on there

3:22

and you can change your slab thickness.

3:24

I usually like mine at around three millimeters.

3:26

When I look at that, one of the things that I wanna do is,

3:28

since we don't provide you with a calcium score,

3:30

I usually like to mip it this way

3:32

so I can detect calcified plaque in the same slice thickness

3:35

as you would with a calcium score.

3:37

This allows you easy direct visualization

3:40

of the calcification and the calcified plaque.

3:42

Its location and extent to the point that, you know, a lot

3:46

of the side of or downsides of not doing a calcium score

3:49

before coronary CT has to do

3:51

with missing calcified plaque depending on your

3:54

injection contrast and settings.

3:56

In this particular case, at 120 KV with an injection rate

4:01

of like six mls per second, that that's not really an issue.

4:04

It's particularly seen when you have much lower KV

4:07

and slower injection rates.

4:08

But here you can see that she's, uh, there's a left vein

4:11

that's gonna bifurcate

4:13

and you can see the, um, you can see the, uh,

4:19

the coronary, the coronary arteries just kind

4:22

of split bifurcate into an LAD and a circumflex.

4:25

You see this first diagonal branch,

4:27

you see a second diagonal branch

4:28

and then you see it kind of wrap around near the apex.

4:32

One of the things that I do when I get to the apex is really

4:35

to ensure that I have accountability

4:36

for distal LAD if there's a wraparound LAD that comes

4:40

around, or more importantly finding out the dominance.

4:43

And by dominance I mean which vessels going

4:45

to provide the posterior descending artery

4:47

posterior lateral branch.

4:49

Here you can see that the circumflex gives, tries

4:51

to really one small early om

4:53

and you see a second om that's kind

4:56

of branch into distal vessels.

4:58

And you see a little bit of a remnant

5:00

of a distal circumflex.

5:01

You can see that the posterior lateral branch

5:04

and the posterior descending arteries are directly

5:07

originating from, uh, from the, uh,

5:12

yeah, yeah, we'll definitely look at the venous

5:14

anatomy in this for short.

5:16

So now in this particular case, you can see a lot

5:19

of more defined coronary venous anatomy

5:21

that you were expecting to

5:23

because of the findings of, um, of, of the actual,

5:28

uh, presence of a coronary sinus.

5:29

So one of the things that I like to do is, when I start

5:32

with this, is, uh, show cross hair center style, uh,

5:38

dot, uh, no, hold on,

5:40

let me bring my cross hair center style here.

5:43

Um, that we can kinda see those.

5:47

And, uh, one of the things that I wanna make sure

5:51

that we have is, uh, move our,

5:55

find the anatomy of the heart in the direction that,

5:58

that we wanna have it.

5:59

So let me put this in here. Large without dot.

6:02

Okay, so now we're here.

6:04

So I tend to align my heart in the short access orientation

6:07

at the beginning of the case

6:09

'cause this will give you anatomical landmarks in a way

6:11

that makes it easier for you to identify things

6:14

and more importantly, identify veins as they originate.

6:18

So veins in the heart are a little bit more challenging in

6:21

the sense of what it becomes, what what becomes where,

6:24

and more importantly, what supplies that.

6:26

So easiest thing that I could begin

6:28

to tell you is actually begin

6:30

with the vein venous outflow tract is how it's empty,

6:33

meaning the coronary sinus is the end,

6:35

meaning the coronary sinus is going to be the venous return

6:38

to all the coronary arteries straight into the right

6:42

atrium and go from there.

6:44

Vessels that follow the, uh, the coronary sinus, you know,

6:48

include a lot of these large gray cardiac, uh,

6:51

the coronary sinus that kind of wraps

6:53

around the lateral wall.

6:55

And then this one's going to follow two particular,

6:57

uh, segments.

6:59

You got the middle cardiac vein, which you should be able

7:01

to see near the bottom of the AV groove.

7:04

And, and you can understand why this is,

7:06

especially along the intraventricular, uh, wall

7:11

along the inferior wall, as you can kind of follow it

7:14

around along the iv, the, the inferior segment.

7:17

And this particular, uh, vein tends to follow parallel

7:21

to the posterior descending artery.

7:23

So I'm going to kind of put my cross hairs on it

7:25

so you can kind of visualize it

7:26

and you can see how it's a much larger size vessel compared

7:30

to the PDA, but they tend to follow in general

7:33

that same pat, that same pattern.

7:35

So middle cardiac vein follows the PDA

7:38

and it drains through that.

7:40

As far as the, uh, the vein

7:43

that comes in the anterior aspect of the LAD,

7:47

the greater cardiac vein, uh, this one in particularly tends

7:51

to follow the course of the LAD

7:53

and the intraventricular groove.

7:55

And you can actually follow it right along here.

7:57

I'm having my cross hairs directly follow it in itself can

8:00

be quite determining, uh, vessel.

8:02

And it is one of those vessels that tends to rotate, uh,

8:06

laterally, uh, through following the course of the LAD.

8:10

Sometimes it goes on top, sometimes it goes

8:12

through the bottom, but that's kind of where,

8:14

where you can kind of define it and, and identify it.

8:17

And last but not least, you have these epicardial branches

8:20

of the coronary sinus.

8:21

That's where some of these vessel branches

8:23

that you'll see here that tend

8:25

to follow the lateral sides of the A group C.

8:27

You can see this entire cardiac vein here,

8:29

and that's the ones that usually tend to follow again,

8:32

coronary sinus, uh, uh, orientation and drainage.

8:36

In this particular case,

8:37

what's really interesting is you can actually see

8:40

how there's literally no wall on the upper aspect

8:43

of the coronary sinus,

8:45

meaning there should be a distinct SEPTA

8:48

or separation here,

8:49

meaning the coronary sinus should not receive any oxygenated

8:53

blood from the left atrium.

8:55

It should be only, uh,

8:57

sending the oxygenated blood right to the right atrium.

9:00

But here you can actually see a clear

9:03

and notable connection between the left atrium

9:06

and the coronary sinus.

9:08

In fact, you can actually see the contrast following all the

9:11

way up to the lateral cardiac veins extending almost into

9:15

the gr into the great cardiac vein near there.

9:17

And following a lot of the middle cardiac vein here,

9:20

inferiorly as, as the contrast tends to flow from there, uh,

9:24

because of the kind of actual shunt that exists.

9:27

So you can see the, the, the can congenital defect

9:30

that exists with it.

9:31

Now, in a patient like this, does this really create issues?

9:35

In some patients it can create coronary steel syndrome

9:38

and particularly if the venous pressures in the,

9:42

in the ventricle in the cord

9:44

and coronary veins tend to be higher.

9:46

But in particular cases like this where, you know,

9:50

you get too concerned about the, the congestion

9:53

or the oxygenation in, in the coronary arteries,

9:56

really there isn't much of a, of a, of a difference

9:59

where it would become clinically significant in,

10:02

in this particular cases.

10:04

Now to put that into perspective, one of the treatments for

10:09

um, coronary artery disease when it gets to be quite severe,

10:13

has actually been mechanisms to actually

10:17

obstruct the coronary sinus to purposely increase the venous

10:22

pressure gradient in the coronary veins to allow for

10:26

that perfusion pressure to be higher in end diastole

10:30

for some of the more distal targets in,

10:33

in the coronary artery.

10:34

So that's the kind of approach

10:35

that you wanna have in this particular case.

10:37

Like I said, we could see that there's disease in the LAD

10:41

and the left vein, nothing that appears to be obstructive,

10:43

mostly in the minimal to mild ranges we discussed.

10:47

You can see same along in the circumflex here.

10:49

Makes it relatively easy for you to kinda follow along and,

10:53

and see how those arteries tend to follow

10:56

the, the distribution.

10:58

The one that catches my attention is always going to,

11:01

it's always the right coronary artery.

11:03

And, and I wanna be able to kinda

11:05

show you a particular approach to kind

11:07

of align the RCA in an chemical orientation that'll make it

11:11

easier for you to interpret.

11:12

First thing I like to do is I like

11:14

to put my blue plane towards the apex and align my annulus

11:18

or the, uh, align my green plane along the annulus of the

11:22

right ventricle.

11:24

And then following.

11:25

Now what's going to be like my pseudo sagittal orientation

11:29

is I like to line up the top of my green plane

11:32

to the bottom of the green plane.

11:33

See kinda pin down this up

11:36

and down aspect of the RCA now that I have

11:38

that you can actually see

11:40

how you create this quote unquote c-arm angulation,

11:44

which is the ability for us to look at the coronary artery

11:49

in a orientation that's, uh,

11:51

right anterior oblique orientation without a co

11:54

or cranial angulation

11:56

as we would see in an invasive angiogram.

11:58

And this really allows you to see both the proximal segment

12:01

of the RCA, the mid segments that this tool as well

12:05

as its branches in relatively ease in a way

12:08

that can be methodical,

12:09

but also allows you to really see complex plaque,

12:13

particularly in long segments of the vessel.

12:16

Here you can tell that both the proximal

12:18

and the mid LAD tend to have pretty extensive disease

12:21

with a severe stenosis right here in the mid RCA greater

12:24

than 70%, uh, with a, as well as some of

12:28

that involved in the distal LAD.

12:30

And you can see the bifurcation here of the pl

12:33

and the PA in, in the artery.

12:35

So in this case, you have the evidence

12:37

of obstructive coronary disease involving the RCA,

12:40

but you also have the incidental finding of a coronary sinus

12:43

that tends to actually have this intriguing

12:45

fistulas connection, right?

12:46

You see how this goes through here?

12:48

There's this other little vein that tends to connect to me

12:51

and it ends up draining directly into the right atrial

12:56

appendage, which is again, one of those really interesting

12:59

and anatomical findings.

13:00

Now, this patient has had over five decades

13:03

with this finding and it's not something that, you know,

13:06

we were too intrigued by or,

13:08

or concerned about needing to repair or replace

13:11

because when n seen had a, an assessment

13:13

of the shunt physiology, there was no evidence

13:16

of left ventricular dilatation

13:17

and no significant, uh, right, right atrial

13:21

or right ventricular dilatation.

13:23

Questions, concerns about case five.

13:25

Does that answer your questions?

13:28

And I can always send you a, um, a,

13:32

an atlas picture for the cardiac veins if we need to, um,

13:37

for, for review for us to include.

13:40

Yes. Perfect. Yeah, yeah,

13:45

I'm definitely happy to do that, that that's not a problem.

13:48

So yeah, so that's what we'll do.

13:53

Okay, any other questions? Any other concerns?

13:58

No, the y graph and yeah, and case four.

14:01

Yeah, that, that, that's a, that's a very, very, very

14:04

interesting case and,

14:05

and it's one of our preferred, uh, cases for discourse

14:09

that y graph one, it's really kind of like your last test

14:14

to assess your ability to answer that question.

14:17

That often comes up with cardiac ct, meaning there are, uh,

14:22

cases where we don't know the anatomy, where we will,

14:26

we will ask for a coronary CT to help us elucidate what

14:31

that artery anatomy is going to be

14:34

and more importantly what we're going to be able

14:36

to do about it in terms of defining the disease

14:40

and more importantly how many grafts

14:42

and where they were utilized, et cetera.

14:44

So I'm going to show you how I use my,

14:48

my approach to evaluating graphs, patency in general, and,

14:53

and we can go from there, right?

14:55

So what we're going to do is I like

14:58

to usually assess bypass grafts in this pretty, uh,

15:02

standard approach where I look at my axial images

15:05

and I like to begin asking the questions.

15:09

One, what kind of artery graft exist?

15:11

And two, where do they tend to go?

15:13

Now as a cardiologist, you kind of already know what type

15:17

of arteries are going to be bypassed.

15:19

Usually for survival purposes there's always an interior

15:23

thoracic or interior mammary lima graft that's always going

15:26

to be bypassed to the LAD if it's involved.

15:29

So I always be on, I'm always on the lookout for that.

15:32

Depending on whether they have disease in the diagonal

15:36

or optus marginals, I expect some sort of venous graft

15:39

or arterial graft to be providing blood flow to the Optus

15:42

and diagonal branches.

15:44

As well as sometimes knowing full well that

15:47

for revascularization purposes the target artery of choice

15:51

that the surgeons can actually reach tend

15:53

to be Optus marginal branches from the circumflex,

15:56

not the actual circumflex proper

15:58

because you can't tie down arteries

16:01

to the circumflex given its location in the AV group.

16:04

And last but not least, the posterior descending artery,

16:07

which is a common target for revascularization.

16:10

So having that background provides you some more information

16:14

on like what are the things that you expect

16:17

and more importantly where you expect them.

16:18

Now we know that the internal thoracic artery is going

16:21

to be coming off usually the subclavian artery.

16:24

So that's one of the areas that I tend to look.

16:27

And it's important to know

16:28

that when you are protocoling these cases, that you want

16:31

to ensure that your field of views

16:33

and your c axis begins way above the clavicle so

16:37

that you can ensure that you have the origin

16:40

of that lima graph.

16:41

'cause that can be very important and challenging.

16:43

It's particularly in these cases

16:45

that when we do invasive coronary angiography, that we tend

16:48

to have the most issues with complications where the,

16:52

the catheter itself, the,

16:54

the mammary catheter can actually cause dissections in the

16:58

interior mammary artery depending on stority and origin.

17:02

So that's why CT is so helpful to kind

17:04

of help answer the question of the anatomy

17:06

of the vessel at the osteum

17:08

and its course once I identify it,

17:10

and you can kind of see here this internal thoracic artery

17:13

from its origin here, you can actually follow it

17:16

because this vessel is going

17:17

to be pulled out by the surgeon.

17:19

Now the surgeons, if you ever seen, get the opportunity

17:22

to do open heart surgery, they will split the sternum,

17:26

lift up half the chest,

17:27

and they will slowly dissect those arteries out

17:30

by putting clips, surgical clips on the branches

17:33

that would feed, you know, some

17:35

of the anterior causal aspects of it.

17:37

And that's what you see. You'll see a lot

17:39

of these little metal artifacts in there.

17:41

And those are the little clips

17:43

that the surgeons tend to put in.

17:45

The nice thing about these clips is they're not very, uh,

17:49

impactful in the sense of like their density, meaning

17:53

that they should not cause a lot of beam hardening artifact.

17:57

As you know, the cabbage wires tend to do

18:00

or other metal artifacts

18:02

and they tend to be outside of the vessel itself,

18:04

meaning they're, they're involving the graft branches,

18:08

not the branch itself.

18:09

So it makes it much easier for you

18:11

to interpret these vessels.

18:12

Once you identify it, you kind

18:14

of follow it down on the axial vessel

18:16

and continue to follow it.

18:17

Now you'll see that there'll be some tortuosity along it

18:20

and you expect it to always follow the, you know, right side

18:23

or the left side I should say, of the uh,

18:26

internal thoracic artery.

18:28

Now here in this one you kind of see

18:30

that there's an intriguing transition.

18:32

You kind of expect the vessel to stay closer to the LAD

18:35

because the LAD should be kind of following this location,

18:39

given the location where the apex of the heart is,

18:41

meaning you're expected target to be here.

18:43

But you see an interesting branching point

18:45

where you see another vessel suddenly appear that's going

18:48

to go towards the posterior aspect of the heart.

18:51

And that's really, really important for us to kind of track

18:54

what it is that it's doing

18:55

and more importantly, where is it continuing.

18:58

And you can follow it here all the way down into its uh,

19:01

it's arterio otomy site.

19:03

Same here with another one of the graphs here.

19:06

As you follow the front of that vessel

19:08

and more importantly where dislocation is

19:11

and where dislocation is, you can see that a vessel's going

19:14

to tie down here but also continue all the way extremely

19:18

down here while it provides another vessel.

19:21

So now that you've identified

19:22

that there's an intriguing anatomy, I'm, I'm gonna be honest

19:25

with you, it's really, really ideal

19:28

to look at your vessels now in your sagittal view.

19:31

So you kind of zoom it, zoom out, grab this, scroll down

19:35

and you're gonna find the lima graph

19:37

that it comes off the top.

19:38

See, you can see it here. So we'll follow it.

19:42

We're gonna scroll down to kind of see its origin,

19:45

see here's the origin of the graft, you see it come down,

19:48

follow its turn.

19:50

We're now here. We continue to follow it down

19:54

and then look at this.

19:55

You can see this graph relatively easy

19:57

and see how it's heading posterior in the heart, kind

20:01

of looking more towards the dia optus marginal branch.

20:04

And you can see how it goes to this vessel here,

20:07

but it's also going to continue all the way down

20:10

to this branch vessel.

20:11

So that's where you get that graft composition.

20:14

Then you see that it's going to

20:18

make an anastomosis here, which is the LAD,

20:21

but also is going to try to reach all the way down here

20:25

into the distal LAD by using another graft.

20:28

So when you see that kind of transition,

20:29

now you have the option down to use your coronal view.

20:33

You kind of see if you can spot

20:35

that intriguing y intersection.

20:38

So using your multiplanar reconstruction,

20:41

what is the best way to put it?

20:43

So put your cross hairs in the middle

20:45

and we'll see if I can get rid of the uh, the dot

20:49

and without dot.

20:50

There you go. And we're going to try

20:53

to see if I can get this to orient for you.

20:55

So you're here rotating this direction, trying

20:59

to rotate this in this direction.

21:02

See that, just align to it.

21:05

And voila, your Y graph becomes very prominent

21:09

and much easier to follow.

21:11

If you center that y graph through here,

21:13

just simply rotating your plane will get you to the top

21:16

and bottom of that along the axial vessel

21:20

and you can kind of follow it easy.

21:22

So see how in the other planes how I rotate through it,

21:25

it'll take you to the target vessels

21:27

or now that you have it in view,

21:29

you simply can just rotate through it.

21:32

See, you can see how that vessel

21:34

and you can see the transition here.

21:35

You can see how this is going to go down to this diagonal,

21:39

but it's also gonna get an additional arterial graphical

21:42

down into the distal aspect of the of the LAD,

21:46

which is an important graft transition for you

21:49

to revascularize with arterial grafts, a diagonal,

21:53

a distal LAD

21:55

and a couple of Optus marginal branches all

21:57

with arterial grafts.

21:59

Now another clue that can help you

22:03

assist if those are involved or not.

22:06

Um, it has to do

22:08

with your internal thoracic on the left side.

22:10

So we know that the right internal thoracic is here

22:13

and if you look closely, uh,

22:15

that thoracic artery on the right

22:17

side is definitely missing.

22:19

Meaning it's not visualized.

22:21

You can see the surgical clips from it,

22:23

but it kinda is nowhere to be found.

22:25

So you know that it's been utilized as part

22:28

of this arterial graft.

22:29

Sometimes they use it as a,

22:31

as a connection towards a vessel,

22:33

but sometimes they usually not.

22:35

And then last but not least, you end up with this graft

22:38

right here in the origin of the aorta.

22:41

That will tend to follow you, follow it along, see

22:44

how it kind of drives around, walks around

22:46

and eventually connects right in here into the PDA.

22:50

So how do we assess the graft anatomy if,

22:53

if you are having even more complex cases?

22:56

So again, another thing

22:58

that I always recommend you do on coronary ct,

23:01

no matter the case, especially if you're having a hard time

23:03

with the targets, is to align on the short axis orientation

23:08

and just follow the arteries.

23:09

You know the native graft artery, you know

23:11

that the LAD is always going to follow

23:14

this anterior ventricular groove.

23:16

So you are expecting to see a graft which you see here,

23:20

get a bypass right there, see that connection, you see

23:24

how this arterial graft is gonna connect to the LAD.

23:26

And then you really just need to look at the distal vessel,

23:29

distal to the graft because the anatomy prior to it,

23:32

of course it's going to be obstructive,

23:34

of course it's gonna have extensive disease.

23:36

That's the whole reason why they had the bypass artery.

23:39

But if you look at it distal to that meaning

23:41

after the anastomosis, that's really what's going

23:44

to dictate your cataract's disease.

23:46

That's the disease we're interested in.

23:48

What does it look like leading from the graft origin,

23:51

the body where it touches down

23:53

and what's the vessel look like after the bypass?

23:55

'cause that's what's really revascularized.

23:58

Sometimes there's retrograde flow that will help,

24:00

but obviously the disease was obstructive enough

24:02

that you needed to bypass beyond the disease.

24:05

So you can see that here.

24:07

You can also follow the circumflex.

24:09

So you can see how the circumflex extensive the disease has

24:13

a lot of plaque,

24:14

but you can also see

24:15

how a graft here just quickly connects into the OM

24:19

and you can see that om too.

24:21

And you can see this other parallel vessel comes down

24:23

and it connects into this artery.

24:25

So another Optus marginal branch

24:27

and that's how you get the lateral territory.

24:29

And then you see this other branch vessel kind

24:32

of follow along here

24:34

and that's the diagonal where it touches down

24:36

and you can see it kind of following along those vessels

24:39

and see you can kind of orient information in a much easier

24:44

to digest, easier to handle crack.

24:47

Now for the RCA you usually can follow here on your two

24:51

chamber view and you really can follow this graft.

24:55

So you can see the graph kinda rotate around, thumb down,

25:00

follow it and let me move this up

25:02

'cause that frontal, that letter is in the way.

25:06

You can follow it and see how it made

25:08

that transition into the anastomosis.

25:10

Very good. You can see how

25:11

that just goes right into that vessel.

25:14

It's very interesting.

25:16

Surgeons have the skill to be able to tie down into vessels

25:20

that are 1.5 millimeters in diameter at the smallest size.

25:24

And that's what really dictates the

25:26

vessels that we care about.

25:27

If a surgeon can tie down to it, we need

25:30

to comment on his disease.

25:31

If a surgeon can't tie down to it, we really don't care

25:34

'cause it's not revascularized.

25:36

By that same token for stents, the smallest stents available

25:39

that you're gonna be able to really have a good result in

25:41

tend to be stents of two and a half millimeters in diameter.

25:44

So again, vessels that that do that tend to do,

25:47

how do we identify collateral circulation and pathways?

25:50

You really don't. Right?

25:51

And that's the difficult thing

25:53

because when you look at the coronary arteries, you're going

25:57

to look at 'em in an end diastolic filling,

25:59

meaning you're going to see the blood flow,

26:02

the contrast located anywhere the contrast could flow.

26:05

You're not having an integrated injection

26:08

with an acquisition happening in real time,

26:10

meaning you're not looking at the anatomy

26:13

as the graphs are getting filled

26:15

and you're watching the contrast flow.

26:17

For you to identify quote unquote collateralization,

26:20

you need to have real time integrate injections.

26:23

And that's only done by invasive angiography.

26:26

That's where you'll be able to see the collateralization.

26:28

As you can see the injection

26:30

of a vessel going from the same side

26:33

or contr laly as the contrast follows those vessels to reach

26:37

to the target vessels.

26:38

But on CT you won't be able to.

26:41

The other thing on CT is, if you think about it, a lot

26:44

of these collateral vessels are going to be very,

26:47

very small, um, micro vasculature vessels

26:51

that you're probably not going to be able to see.

26:53

'cause the spatial resolution we're talking vessels like 0.2

26:56

millimeters in diameter that you just, you just can't see

27:00

with CT yet.

27:01

So yes, why and when did they use y grafts?

27:04

So we use y grafts when we're trying to, uh, get

27:08

as many as we can.

27:10

Arterial grafts, you wanna a arterial graft.

27:13

If you have good target vessels,

27:15

meaning the om branches tend to be at least two

27:17

and a half millimeters or larger, you can provide

27:20

as much vascular territory.

27:22

And what you really need is you really need, uh,

27:25

for arterial grafts to do well

27:27

and to mature, you need to read

27:29

high grade stenosis in very proximal

27:31

segments of the vessels.

27:32

Meaning if you have an obtuse marginal branch

27:36

that the disease leading to it, say it's, uh,

27:38

circumflex proximal

27:40

and he has like a 70 99% stenosis, mostly being 70%,

27:44

75% let's say, that's not going to have enough

27:48

of a pressure gradient

27:49

that if you put down an arterial graft, it's going

27:52

to mature the graft well enough.

27:55

Remember, arterial grafts really need to be able

27:57

to have almost no competitive flow to mature.

28:01

And that's why we tend

28:02

to be a little bit more selective on rafts.

28:04

They're not very common, they're not often used.

28:07

Arterial grafts tend to be utilized,

28:09

but this y graft is used to be able to use

28:12

multiple arterial conduits.

28:13

And we're talking, you gotta right in internal thoracic

28:17

artery that that got separated from the chest, that got used

28:20

as a skip graft to get to the Optus marginals as well as a,

28:24

uh, a radial artery that gets used to the distal LAD

28:28

to be able to reach that diagonal branch

28:31

and that, uh, distal segment of the LAD that you couldn't

28:34

otherwise achieve with just one long

28:37

internal thoracic artery.

28:38

The other thing that can also help,

28:40

and you know, this is one of the options that you do have

28:43

that you can always try to do is, uh,

28:47

on your settings, you can always do the, uh,

28:53

the cardiac setting where it will be able to remove a lot

28:58

of the bone, right?

28:59

And then you'll be able to see the graphs.

29:01

So if you go to workflow

29:03

and you do, um, the the coronary arteries, it should be able

29:08

to kind of show you these, uh,

29:10

3D volume data sets without the bone.

29:13

So it, it will do bone extraction per se.

29:16

So let me see if I can do cardiac one.

29:18

And then it'll, it'll remove the, the, the,

29:21

there you go see, it'll remove the, the contrast from it

29:25

and it'll allow you to kinda see the vessel.

29:27

So the three DI don't necessarily recommend you use this

29:31

for, uh, diagnostic purposes,

29:35

but for, uh, for particularly saying is there stenosis

29:38

or not, but from a, is there anything here that I need

29:42

to be aware of, like where the graphs come from?

29:45

This can actually be quite helpful in some

29:47

of these complex cases.

29:49

You can see how the graft connects here.

29:51

See, you can see that very clearly

29:53

how this arterial graft tends to follow down

29:55

and connect one twice.

29:56

Here you can see how the,

29:59

the graft here connects here towards the diagonal

30:03

and then there's an additional arterial graft down here

30:06

that tends to rotate and, and go through.

30:09

And then you can follow this other

30:11

arterial graft on the right side and,

30:14

and follow it down all the way into that vessel.

30:17

See? Very good. You guys are asking very good questions.

30:20

So that's, that's why we use those.

30:24

Yeah, of course, of course. Any other questions?

30:27

This is a tough case and a lot

30:29

of you guys did a good job with it.

30:30

But again, in this cases we often get overwhelmed with like,

30:34

oh, there's extensive disease, there's

30:35

so many findings on the native coronary arteries.

30:38

I might miss a complete total occlusion there.

30:41

It's irrelevant. I think you really should focus more on

30:44

what does the graft looks like

30:46

and what does the arteries look like after that graft.

30:49

In this particular case, when you think about it, right,

30:52

there's only a moderate stenosis in this saphenous venous

30:55

graft, right in the, in that first component

30:58

of the vein graft, which is not uncommon, right?

31:00

Right at the osteum is where we,

31:02

we see the disease in this particular case.

31:04

And, and I'll point it out here, you can see

31:06

that narrowing right there.

31:08

That's the pathology of this

31:09

and that's why this graft is not as noticeable as,

31:11

as you'd want it to be.

31:13

But that really is what's going to determine your CAD rats.

31:16

The distal targets really,

31:18

they have no significant stenosis in there

31:21

that would say we need to redo open heart surgery

31:24

or we need to do any type of additional uh, uh, testing.

31:28

So it answers the question of what's a pathology of disease?

31:31

If there are symptoms, what did the graphs look like?

31:34

And pre-procedural planning for revascularization,

31:37

if the patient has significant symptoms, et cetera.

31:40

It's quite helpful. Back in the day we used to be able

31:43

to say like, oh, let's go through this graft

31:45

and try to open it and fill it with stents, et cetera.

31:47

But that has not been very successful.

31:50

A lot of the strategies now focus on

31:52

what are the coronary anatomy findings that we can use

31:55

to be able to determine if we can get this native RCA

32:00

open and revascularize the vessel itself to,

32:04

to alleviate the symptoms.

32:05

So we're focusing revascularization now

32:08

of the native vessels rather than opening off venous grafts

32:12

or arterial grafts that could potentially get thrombose

32:15

and disease because of the native nature of the, of,

32:18

of their endothelium really,

32:20

which is quite fenestrated 'cause it's a venous.

32:22

So very good. Very good. Any other questions?

32:26

Those are two tough cases from this one.

32:32

Okay. Let's see. How do we identify coronary dissection?

32:36

Excellent. So that brings us back to that cool case.

32:39

Yes, you're asking all the, all the good questions.

32:42

So I think this one case, case two is the one

32:45

that we had evidence of a prior coronary artery dissection.

32:48

So when you have, uh, a native coronary artery dissection,

32:53

you're gonna have a couple of of options when it comes

32:56

to cardiac ct.

32:58

And I think on the references for case two report

33:01

or one of the other cases coming up, I, I can't remember,

33:04

I know for a fact I sent that as a reference.

33:06

So throughout this course you will have a review article

33:09

written by one of my colleagues and fellowship Dr.

33:12

Uh, Sumit Gupta, about

33:15

how we can use coronary CT findings to identify

33:18

coronary artery dissections.

33:20

And it's a great article,

33:21

but in summary, there's obviously the type of

33:26

anatomical finding in the arterial wall that's going

33:28

to be able to help alleviate some of this in.

33:31

Let, let's get to it. In this particular case, we noticed

33:35

that there's an intriguing amount

33:37

of black characteristic in the native left main,

33:40

particularly we're talking about the degree of, uh,

33:44

the thero sclerotic appearing type

33:47

of disease in the proximal vessel.

33:50

So one of the things that kind of helps distinguish

33:52

coronary artery dissections from not coronary art from

33:57

atherosclerotic disease is one, the presence

33:59

of atherosclerotic disease in the other vessels.

34:02

If you have extensive coronary thro sclerosis,

34:04

the likelihood that you had a coronary dissection

34:06

as the etiology of symptoms and disease is much lower

34:10

because disease breeds disease.

34:13

So that's one of the tell signs.

34:14

There's not a lot of extensive thro sclerosis.

34:17

There are cases, and I've come across this in clinical,

34:19

where patients can have both minimal thro disease

34:23

and then have dissections,

34:24

but in general, as a rule there,

34:25

coronary thro sclerosis does not tend to be as extensive.

34:28

So that's one. Two, the characteristics of the actual wall

34:32

or the atherosclerosis in the, in the vessel.

34:35

And, and this is where I wanted to point out a lot of this,

34:38

in these dis heeled dissections

34:41

or in dissecting coronary arteries tends

34:43

to be this particularly, uh, wall stranding that you see.

34:47

It's what we think of it as pericardial wall,

34:50

uh, fat stranding.

34:51

And in this pericardial fat stranding

34:54

you can actually see some of the residual, uh, inflammation

34:59

or or edema edematous findings.

35:02

Usually it tends to be more in the recent

35:04

acute or acute cases.

35:06

In this particular case,

35:07

the patient had had recent bypass surgery shortly

35:11

after her event of the dissection

35:13

and she had recurring chest pain.

35:14

So we wanted to reevaluate her disease given

35:17

that she had recurring chest pain

35:19

with at least a minimal implant of instrument station

35:21

with direct angiography to be able to assess.

35:24

So that's what you can see some of this, uh, fat stranding

35:27

that's still kind of residual.

35:29

Last but not least, there's this plaque you'll be able

35:32

to kind of see around the vessel walls

35:35

and oftentimes people think like, well, could

35:37

that be noncalcified plaque or ths cardiac plaque?

35:41

A lot of it and still have the house full unit attenuation

35:46

of thrombus like an acute hematoma.

35:48

And we're talking in the 45 household unit range up

35:51

to a hundred and forty five, a hundred ninety house full

35:54

unit ranges.

35:55

That kind of hounds for range tends to be more indicative

35:58

of like a dissecting hematoma.

36:01

Sometimes if the hemo, if the flap tends to be significant,

36:04

you'll be able to know, uh, to see it better.

36:07

But overall the three main teal signs tend to be important.

36:10

Now if you see that, you know,

36:12

this vessel like right here tapers down

36:15

and the vessel itself does not have a lot

36:18

of a ths caric disease,

36:19

but has like very unusual type of focal stenosis

36:22

that mimics a ths sclerosis

36:24

with the pericardial advanced stranding

36:26

and then the inma wall thickening that tends to match that

36:29

of a heel hematoma or an ocurrent hematoma.

36:33

Those tend to be some of the, the 10 tail signs of, of,

36:37

you know, a recent healed dissection.

36:40

So, or, or a recent, uh,

36:43

umca spontaneous coronary art dissection.

36:45

So I know that there's gonna be another case in the course

36:48

that you'll have that specifically focused with that,

36:52

that we have MRI correlation for and we included it.

36:55

So being on the lookout for that,

36:57

and I know on that particular scan we provide you

37:01

with like the instructions

37:03

and the mapping for plaque analysis on POM tech to be able

37:07

to kind of show you how you can measure those houseful units

37:10

and assess that plaque.

37:11

But more importantly also being able to utilize some

37:15

of the other findings since they were so classic on

37:18

that case and the article for your reference for you

37:21

to be able to look at that.

37:23

So, so be on the lookout and here you can see it,

37:25

but it's not as classic as it would be for more

37:28

of a consistent teaching case.

37:30

So very good. Any other questions?

37:38

Any others good questions? This is a, this is a tough one.

37:46

Okay. And then in this particular case, you know, the,

37:50

the thing that kind of tends to do this case over is, uh,

37:54

you know, we did not go all the way up above the clavicles.

37:59

So you can get pretty coronary CT

38:01

that are non-diagnostic if you don't end up going

38:03

to the clavicles to, to find the disease

38:06

with where you need it to.

38:08

So then that can be a certain limitation of the anatomy.

38:12

So very good. Any other questions? Any other concerns?

38:18

Graft complications? So complications of grafts, right.

38:23

In general, when it comes to graft anatomy,

38:26

the most common complication you're going

38:28

to have are gonna be associated with the venous grafts.

38:30

The venous grafts tend to have

38:33

a fenestrated lamin propria, meaning that they're prone

38:37

to a lot of early sclerotic disease, a lot of inflammation

38:42

and a lot of thrombosis.

38:44

And what that leads to is a very variable amount

38:47

of graft patency.

38:48

You know, we're talking this graft can go down as early

38:52

as two weeks or same day

38:54

after surgery within 24 hours up

38:56

to like weeks after surgery.

38:57

And it can last up to 10 years post-surgery.

39:00

Meaning if you see a vein graft that's been there

39:02

for 15 years, take a picture, send it to me

39:05

and let me know who the surgeon was

39:06

because that person has got an outstanding

39:09

outcome beyond that.

39:10

So those graphs tend to in general be, be graphs

39:15

that are not, are not known for their longevity.

39:18

Uh, a lot of them can from both, a lot of them can dissect,

39:22

a lot of them can have severe stenosis

39:25

and a lot of 'em tend to have a lot

39:27

of embolization if they get instrumented on.

39:30

Meaning unlike the coronary arteries, when we go in there

39:34

with wires and balloons

39:36

and stents where we can kind of get away with some

39:38

of the injury to those vessels in vein grafts, any movement

39:41

that touches those grafts essentially leads to, you know,

39:44

earlier deterioration of the graft,

39:45

more aggressive atherosclerotic disease

39:48

and more importantly, the type of absorption

39:50

of the stent tends to be significantly different in a vein

39:53

than it is in an artery.

39:54

As you know, we have known in vein graft disease for,

39:58

for a very long time.

40:00

So that's the most common complication

40:02

you see with vein grafts.

40:03

Vein grafts in general can also have issues

40:06

with their ostia, right, right where the graft is implanted,

40:11

how the graft is implanted varies, right?

40:14

Looking at the, the aneurysms that can develop here, uh,

40:18

they can actually have giant aneurysms there

40:21

that can develop from the graft itself depending on the type

40:24

of pressure that they get,

40:25

particularly if there was recent instrumentation

40:28

or prior instrumentation.

40:30

And also you can also look at disease

40:32

and more importantly, how well they

40:34

develop a thro sclerosis.

40:35

Here in this particular case, you know,

40:37

even though the graft is relatively new, you can kind of see

40:41

how the graft itself tends to have a lot of like on,

40:45

you know, endothelial abnormalities already developing.

40:49

And this graft is not something

40:51

that's been old enough for a long time.

40:53

So the endothelialization

40:56

for them tends to be a little different.

40:57

Thanks thing about this venous graft is they really don't,

41:00

they need a significant stenosis, a greater than 60,

41:03

70% stenosis for them to mature.

41:06

Unlike arterial grafts, they don't necessarily need that 99,

41:10

almost a hundred percent stenosis for them to mature as well

41:13

as an arterial graft.

41:14

That that's, that's a complication.

41:16

So that's an important thing to know As far as, uh,

41:22

arterial grafts are con are concerned,

41:24

the most common complication

41:26

that you're gonna have from an arterial

41:27

graft is a dissection.

41:29

And that dissection can occur from

41:32

either instrumentation at the time of surgical implantation,

41:35

meaning when you're clipping these grafts,

41:38

you can actually dissect the vessel.

41:40

That's an actual awful feeling that occurs to,

41:43

to some unfortunate patients, but it's not unheard of.

41:47

And more importantly, iatrogenic dissections that tend

41:49

to occur when we do an invasive diagnostic angiogram

41:53

and we can dissect a vessel that can cause an intimal tear

41:57

that can potentially be fatal in

41:58

some patients as a complication.

42:00

'cause if they are bypassed to a major LAD like in this case

42:04

and that vessel is suddenly obstructive

42:05

and has an acute infarction,

42:07

that could lead into a significant bad outcome.

42:10

The nice thing about these arterial grafts,

42:12

they are actually, uh, not fenestrated

42:16

in their lamina propria, meaning that arterial wall tends

42:20

to be pretty resistant to atherosclerotic disease,

42:23

meaning they tend to have a very long, long survival,

42:27

meaning the patency rates on arterial grafts,

42:30

particularly Lima grafts, tends to exceed that

42:34

of the patient's expected mortality

42:36

and survival, meaning patients will die without,

42:39

with their gra lima grafts still being patent from other

42:42

causes even though they had bypass surgery 20,

42:45

30 years before.

42:46

So their patency are definitely there,

42:48

not the same can be said from like reads

42:51

and radial grafts that tend to be free arterial, uh,

42:55

grafts overall compared

42:57

to a vein graft in the right patient, they tend

42:59

to have much higher patency,

43:01

but in general you'll find that the arterial grafts tend

43:04

to have less complications outside of, you know,

43:06

the recent instrumentation and placement

43:09

and more importantly, assuming that when they are evaluated

43:11

with a diagnostic angiogram that the operator's comp

43:15

competent and, and has experienced engaging those graphs.

43:18

So that's what I would tell you or for that perspective.

43:21

So hopefully that answers your question.

43:24

Any other questions we have?

43:32

Okay, excellent. Very good.

43:37

So let's see. We've looked at the Y graph case,

43:40

which is a great one.

43:41

Uh, we can look at case one, which was one that has like,

43:45

you know, some of the graph complications

43:46

that, that we tend to see.

43:48

So I'll load it up so you guys can see it.

43:54

And in this case you can see exactly those,

43:58

those complications from it.

44:00

Now, when you look at vein graphs, it's important to know

44:03

what kind of graphs you'd expect to go where.

44:05

So if you look at your coronal case, right,

44:07

you're gonna have graphs that tend to come across

44:11

and go into the diagonals

44:13

and graphs that will come into your Optus marginals.

44:16

Uh, graphs that tend to be higher up, tend

44:19

to be more diagonal, re-oriented graphs that tend

44:22

to be lower down tends to be more, um,

44:25

obtuse marginal oriented given the, given the orientation.

44:29

Now in this particular case, you can can see how

44:32

there is a graft that's been accessed,

44:37

uh, here, see there's this graft

44:40

and then there's this other graft.

44:42

And this particular graft is completely occluded already

44:45

from exactly the things that we talked about earlier.

44:47

Th sclerosis, very thrombotic disease, uh, in manipulation,

44:52

while these other, uh, venous graft still relatively patent.

44:56

And you'll see this big wide thing here,

44:58

they're called markers, arterial graft markers, meaning

45:02

where the surgeons used to not anymore leave, uh, markers

45:06

that you could see on x-ray markers

45:08

that you could see on invasive angiogram that will tell you

45:11

where the grafts were inserted.

45:13

So when you were doing an invasive coronary angiogram,

45:15

you would just move your cath diagnostic catheter in

45:18

that direction and engage the catheter for that purpose.

45:22

So here you can see that there's one separate graft here

45:25

that tends to be the graft that goes towards the, uh, PDA

45:29

and then there's this other venous graft that was going

45:31

to another part of the RCA that we, we really don't know

45:35

where, where that would've been given

45:37

that the graft itself is secluded and,

45:40

and the graft anatomy here tends to be more of that.

45:43

So this one's a posterior lateral graft

45:46

that's still open while the other one was likely a serial

45:49

descending artery graft that's, that's now occluded graft

45:52

to the diagonals here probably occurred.

45:55

You can see some of these aneurysms that could be component

45:58

to that, but I'm guessing they're not

46:00

because if a surgeon left markers for a PD, a graft,

46:03

it probably would've left markers for the other graphs.

46:06

Sometimes in bypass patients you'll see this from pledges,

46:09

surgical pledges, and sometimes you'll see some aneurysms in

46:12

the early ascending aorta, very focal ones that those tend

46:17

to be the sites where the, uh, pump was initially inserted

46:20

or, or where they arrested the, the,

46:22

the heart when they did the injection, uh, cardiac arrest

46:26

or cardioplegia at the time of surgery.

46:28

So you'll see that again, a high quality exam

46:31

where you can see the origin

46:32

of the le left internal thoracic artery

46:34

and you can actually follow that into the,

46:38

into the arterio site here.

46:39

So when it comes to arterio site, make sure you align them

46:43

and then really just follow it on the, on the,

46:46

on the sagittal

46:47

or corona, whichever one gets you the, the clearest view of

46:51

of that anastomosis.

46:52

And you can kind of move things around in your planes

46:56

to kind of ensure that you are in that location

46:59

that allows you to clearly see the vessel without any,

47:03

any complications or issues.

47:04

So, very good. Any other questions? Any other concerns?

47:11

How do we identify by spirogram?

47:13

So we have an entire section on that, on coming up

47:17

with the TAVR cases, right?

47:19

And a couple of those tend to be pretty distinct

47:22

bipa uh, bicuspid valves.

47:24

The defacto for sure way to do it is

47:27

to see the valve open and close.

47:28

It's kind of hard to admit a bicuspid aortic valve if you

47:32

see it open and close

47:33

and you see only, uh, a raffi with, with fusion of the left

47:38

or right coronary cusp

47:39

or any of the other coronary leaflet, uh,

47:42

that tend to be fused.

47:43

So that's easy. There are some of us that believe

47:46

that here in diastole, as you can tell here,

47:49

you can see the, the rafes

47:51

or like the sub, the commissural lines in the coronary in

47:55

the coronary leaflets.

47:57

And you can follow these commissural lines all the

48:01

way into the al tubular junction.

48:02

See, you can see it here, you can see it here,

48:04

you can see it here and then they

48:06

kind of gradually disappear.

48:08

But you can see three distinct previous, uh,

48:10

indentations from that mo uh, there's some of us

48:13

that believe that that is sufficient for you to be able

48:16

to say tri leaflet versus bicuspid, meaning

48:19

that indentation tends to be absent in patients where

48:22

that fusion of the commiss lines occurs.

48:25

Meaning you won't see it if it's bicuspid valve,

48:28

but if you want to know

48:29

with a hundred percent certainty without any degree of

48:34

of failure, you need to see the valve open and close.

48:37

And if you have a diastolic diastolic gated CT scan,

48:41

you're not gonna be able to do that without doing that.

48:44

So most of the cases in your reports, you'll see

48:47

that we put the tri leaflet aortic valve based on

48:50

that particular finding.

48:51

When we get to the TAVR cases, you'll be able

48:54

to identify bicuspid versus non bicuspid

48:57

and we go over the specific anatomical nomenclature

49:00

and findings for, for those valves.

49:03

'cause that's important and it's more importantly an

49:05

implication what it has on TAVR cases.

49:07

So very good. Very good. Very good. Any other questions?

49:12

I think we got all the, all the cases that we needed to do.

49:15

We, we kind of went through and

49:17

and answered all the important questions that that,

49:20

that we had in that perspective.

49:25

Very good. And then let me pull up case four

49:28

so we can see this one, this was a case of somebody

49:31

that had an aortic replacement

49:33

that the valve was put in place

49:36

and you can see the valve here in this particular case when

49:39

the roots were repaired

49:40

and there, there were those things, I like

49:42

to orient my planes into the valve itself

49:46

and then follow the, the graft anatomy itself.

49:50

And here you can clearly see

49:51

how this is severely anastomosis without having

49:54

to do much investigation.

49:56

So you can see how the left main had been previously opened

49:59

and evaluated and then you can kind of see how

50:03

that stent ended up looking for stent graft anatomy.

50:07

I like to zoom in, I like to move my windows

50:10

and I like to really trying to soften that kernel, uh,

50:14

to decrease the blooming artifact.

50:16

So I move the, I move my, um,

50:21

access orientation in place

50:22

and you can kind of see how really y coronary ct, at least

50:27

by the current, um, scanner technology outside

50:31

of photon counting scanners can allow you

50:33

to see for patency.

50:34

But the degree of instant rib stenosis becomes really

50:37

challenging because of the natural blooming artifact.

50:40

No matter what way you window, no matter what kind

50:43

of sharp kernel reconstruction algorithm you have,

50:46

if it's a stent greater than three millimeters,

50:48

this will be no problem assessing its patency.

50:51

But any stent usually in the lower end of

50:53

that becomes more challenging.

50:55

Photon counting CT images for some

50:57

of these stents have demonstrated that they're just as good

51:00

as an invasive coronary angiogram, particularly

51:03

with larger stents

51:04

and in particularly where the, uh, the

51:09

reconstructions for those tend to be in the extra sharp

51:13

reconstructions and in some

51:15

of the more sophisticated photon counting algorithms.

51:18

So very good.

51:20

But yeah, you can see the osteo RCA stenosis there

51:24

and then the bypass graft

51:25

and the thickening from the graft repair itself.

51:28

Right, right. Along that very good.

51:31

Last but not least, any other questions? Anything else?

51:34

We got about eight minutes left.

51:35

I'm here for you to answer any questions about these cases

51:39

or any other, um, information you have.

51:42

Hopefully you're enjoying this course.

51:44

It's the, the cases have gotten a lot more challenging

51:46

as you could go on from week one all the way

51:49

to now starting week, uh, next week, week six review.

51:53

So very good. Or week seven. Yeah, you guys are week seven.

51:58

I'm ready. Nope.

52:04

Okay, well now that we have that, uh,

52:07

I won't take any more of your time.

52:09

So if you think of anything else, please email us

52:12

and I will be grading your week seven cases

52:16

and we'll have office hours next week,

52:17

same time, safe place.

52:19

And hopefully I will see you all here

52:21

so we can get all this taken care of.

52:23

Of course. Happy to help. I'm here for you.

52:25

Hope you're enjoying it. Of

52:26

course, you guys have a good evening.

52:27

Take good care.