0:00

Thank you for attending the lecture today.

0:03

Um, Dr.

0:04

Lorenz will be reviewing introduction to coronary CT Angi.

0:09

Um, as usual, we encourage you to turn on your cameras

0:13

and, um, let us know if you have any questions or comments.

0:15

You can use the hand raise emoji in Slack,

0:19

or you can just ask Dr.

0:20

Lorenz directly, or if you're more comfortable,

0:22

you can put your questions in the chat.

0:24

So, Dr. Lorenz, whenever you're ready.

0:27

Okay, so I've got about 53 minutes

0:30

and, um, there is a PowerPoint presentation,

0:33

which is available to you, Dr.

0:34

Fontes and I, uh, one of the cool things, uh,

0:37

about the military is there is no payment

0:42

for extra personality.

0:44

You just get slung into a place and you get to work it out.

0:47

So, cardiology, radiology, if you did your fellowship,

0:50

you went to great places, um, then guess what,

0:53

you're on the cardiac imaging.

0:55

And so that's something fantastic.

0:57

Uh, some programs, of course, are very, very strict, um,

1:02

in terms of pathways

1:03

or, uh, specialists taking care of certain things such

1:06

as cardiac imaging, cardiology

1:08

or cardiac imaging or radiology.

1:10

Um, good things and bad things, of course, with that.

1:12

So, multidisciplinary multispecialty, um, in the military

1:17

where we both worked together

1:18

and when we created this, um, PowerPoint presentation.

1:22

So outline for today is we're gonna go through some

1:24

of the very, very nuts

1:25

and bolts, um, of, of, uh, cardiac imaging acquisition

1:30

and reporting, and some things

1:31

that we threw in there in terms of just

1:34

to keep you thought process wise on how

1:37

to deploy a cardiac imaging program.

1:40

This is just a starting spot.

1:41

In fact, I was just looking at some of our, um, um,

1:44

text group threads,

1:46

and we're already talking about, um, how to deploy out, uh,

1:49

systolic only acquisition, which allows you then

1:52

to have no nurse and, um, you know, NTG paste

1:56

and no medication for heart rate optimization.

1:59

Um, so you can deploy that at essentially

2:01

autonomous imaging centers.

2:03

And so the cardiologist, radiologists, all of us are kind

2:06

of inputting on that and how we can do it.

2:07

So by no means is this definitive.

2:10

This is just starting spot.

2:12

I also have two, um, um, articles that I wanted

2:16

to review just because they,

2:17

they are just cornerstone articles, and so we'll get, so

2:20

unless there's any, uh, questions the moment,

2:22

then we will get started.

2:24

And, uh, looks like I got my little chat message up here

2:27

so we can see how this goes.

2:29

But for many of you, you're, you have had an introduction

2:34

to coronary, um, angiography in terms of seeing, um,

2:38

angiography acts with acquisition for the vascular tree,

2:41

either of carotid neuro neurovascular,

2:44

and abdominal and lower extremity.

2:46

So the idea of an anatomic based assumption

2:51

that from a linear standpoint, that the higher the degree

2:55

of stenosis from zero to 100%

2:58

correlates may not be causative,

3:00

but correlates anatomically

3:04

to a stenosis percentage that you can deliver in a tree

3:08

of decision making to a clinician as to how

3:12

to best deploy resources is essentially

3:14

what coronary imaging

3:16

and coronary functional, um, decisions are made on.

3:20

So the anatomy base of zero to 100%.

3:25

Um, and of course the interval breakdown of

3:28

that is essentially what we've done

3:30

for many generations in other angiographic evaluations

3:34

of the, the human body, that part's not different.

3:38

The names obviously the nomenclature

3:40

and some of the other components are a little bit different

3:43

in the nitty gritty interpretation of it.

3:46

I'll also side note that anatomy was not, interestingly,

3:50

the first way of evaluating cardiac, uh,

3:54

cardiac disease.

3:55

It was actually the opposite, which is functional.

3:58

And, uh, interestingly functional did not turn out

4:02

to be the best way of evaluating coronary disease.

4:05

Um, it's not very specific

4:08

or potentially sensitive, um, to, based on the type of

4:12

detector, um, or image acquisition, um, to nailing out

4:16

what is the root cause.

4:18

So although functionality was

4:21

used primarily in cardiac imaging

4:23

and cardiac imaging disease, um, the methodology to do

4:28

that was not very good, uh, for a very long time

4:31

until CT based, um, has come along to kind

4:34

of nail out the anatomy portion of it.

4:36

But interestingly, functional is how you treat it still.

4:41

So are we gonna come to a point

4:42

where the functional treatment is still the

4:45

best case cost-effective?

4:46

Um, may, you know, something

4:48

that avoids major adverse cardiac events?

4:51

We don't know yet. There's actually some really good studies

4:53

that are going out there right now.

4:54

If the diagnostic of anatomy first

4:59

trends out to be that the diagnostic, uh,

5:02

in clinical treatment of anatomy first is best, particularly

5:05

as we move into preventative medicine.

5:07

So I can't wait to see your comments on that.

5:10

But in the interim, let's just dive into this PowerPoint

5:12

real quick and just, um, kind

5:14

of go through a few little things.

5:15

So what factors, of course, many factors play into role.

5:18

What kind of scanner do you have?

5:20

What kind of scanner constraints in terms of the cost

5:22

of the scanner, where it's located,

5:24

where your patient's located, and what kind of deployment?

5:27

Cardiac imaging for acute coronary disease.

5:30

Um, so such as, um, you know, uh, a urgent care center

5:34

or, um, you know, a a another type

5:36

of facility like an ER facility.

5:38

What kind of patient related factors?

5:40

And these are probably the biggest thing.

5:42

And by patient related, of course, we're talking morphologic

5:45

such as how big your patient is, BMI, um,

5:49

or sometimes if your patients are more male

5:52

or more female, contrast related factors, of course,

5:55

play a role into this too.

5:58

So the right fit, right patient is always the big thing.

6:00

There's several different guidelines that kind of go

6:03

through this in detail.

6:05

I would highlight, um, hopefully you can see my screen here,

6:08

the, the 2021, um,

6:10

chest pain guideline is probably the better one

6:13

in really breaking it down.

6:14

Now, even further than that, I have my cheat sheet.

6:18

I have cheat sheet for academic, one for outpatient center,

6:21

and then autonomous, um, imaging patient centers.

6:24

Uh, we have one specifically for Texas

6:27

because there's a little bit of a larger BMI in that area.

6:29

And then, um, I also read for several LA locations on both

6:34

of our US coasts, so New York and, um, California

6:37

and West Coast and stuff.

6:38

And that's not the same BMI,

6:40

but there is an absolute importance on

6:44

arriving at the right BMI for, um, milli amper penetration

6:48

and obviously dosing.

6:51

Okay, contraindications. Let's just get these out quick.

6:54

You, as the subject matter expert, are the one who can say

6:57

what is allowed, not allowed.

6:59

Although these are guidelines,

7:00

there is no real strict rule on it.

7:03

Even the a UC criteria guidelines don't really

7:08

tie your hands behind your back

7:10

and say, you are not allowed to do this.

7:11

They're guidelines, you as the performative, um,

7:15

and physician gets to decide this.

7:18

But as usual, in use of radiation contrast, um,

7:23

size, the patient and, um, the current fitness

7:26

of the patient that is pregnant, not pregnant, postpartum,

7:28

whatever is really going to deliver

7:31

what is the appropriate acquisition.

7:33

So of course, um, there are some things related to pregnance

7:37

and, and possibly a pregnant.

7:39

I would advise you to consider that most

7:42

of the Millie Seaver acquisitions right now are just

7:46

fantastically low in the normal acquisition comparatively

7:50

to, um, nuclear

7:52

or some other methodologies such as, um,

7:54

invasive coronary angiography.

7:55

So don't discount CT comparatively

7:58

unless you're looking at an Appleton apple,

8:01

milli seavert temple resolution.

8:03

This is probably the bigger one.

8:05

Really, we need something that's gonna be able to, um,

8:09

acquire something on an individual

8:11

who has an optimized heart rate.

8:14

Now for my current machines, um, you know,

8:17

this is second generation 2.5 ish, so not naone

8:20

or photon counting, but something a little bit, uh, less so,

8:24

uh, Siemens force sort of level stuff.

8:26

Um, canon equian, uh,

8:30

GE has some apex, um, things.

8:32

Those can definitely have a,

8:34

a larger range from obviously 50, um,

8:37

to about 75 depending on what kind

8:40

of iterative reconstructions

8:41

and algorithmic reconstructions are available there.

8:44

Poor image quality, hate to tell you this,

8:47

but you're going into a field where there's gonna be motion.

8:50

This thing is moving. Um, the heart

8:52

and the pulsatile nature of the coronary arteries, um, is

8:56

that there's gonna be motion.

8:58

And so I'm gonna, we're gonna teach you on how to take

9:00

that motion and potentially learn how to discount more

9:04

of the, um, the larger components of motion.

9:07

But obviously the acquisition should be the,

9:09

the best starving place for that.

9:12

Um, unable to receive vasodilatory medications such as,

9:16

um, nitroglycerins.

9:18

There are of course some medications that could be involved

9:21

with that and may not be the, the best,

9:24

uh, situation for you.

9:26

Um, do, do, do contrast contraindications, anaphylaxis,

9:30

higher risk for contrast induced nephropathy.

9:33

Uh, I mean, we not really in that area anymore

9:37

where there's a high, uh, molar, you know, concentration of,

9:41

of, of a type of iodine that causes that.

9:43

In fact, in usually the a CR pushes something, um,

9:48

early in the spring American cardio, uh, college

9:51

of radiology, and then by summer fall they retract that

9:55

and say, well, well, you know, it, it may not.

9:58

But essentially contrast

10:00

and contrast related contraindications to other organs,

10:03

solid organs such as the,

10:04

the kidneys hasn't really burned out.

10:06

So I try to not think about that as being a consequence

10:11

of not doing the exam.

10:12

We're talking chest pain just like we do for pulmonary em.

10:15

Um, embolism evaluation.

10:17

It's sort of one of the things you're just gonna do.

10:19

So you try to optimize the factors, right?

10:22

So a little bit more about optimization.

10:24

There are some really important things to kind

10:26

of consider here, but I think the most important one is

10:29

that the patient is appropriately prepared

10:32

that there are some things that they're going to need to do

10:34

before in the morning of.

10:36

So, uh, drink fluids, that's a big thing, particularly

10:39

for our older crowd because the vessels can get smaller

10:41

and there is of course a microvascular disease differential

10:45

if you are of a, you know, female

10:47

or, uh, potentially even younger

10:49

that you might wanna worry about.

10:51

But for the most of the part,

10:52

you want a bigger fatter vessel.

10:54

And, and sometimes that has to do with blood volume.

10:56

Now, I'll tell you that most of the healthy individuals,

10:58

the body's pretty smart, so it's not gonna leave all that

11:02

blood volume in the primary space, um, for you just

11:07

because you wanted big plumpy, um, coronary arteries.

11:10

Um, it's actually gonna move it out

11:11

and there's gonna be an excretion thing

11:13

that you're gonna work with.

11:14

So that theory doesn't really hold too much.

11:18

I think the main one probably is gonna be

11:20

as medications that could do it.

11:21

Caffeinated products potentially can contra, uh, indicate,

11:25

you know, some of the, the blood pressure medications.

11:29

Um, yeah, that's a possibility.

11:30

But I think one of the hard

11:33

and fast ones is maybe va vasodilatory medications

11:36

that are already in use.

11:39

Okay, well, just so that we're all on the same page here,

11:42

um, for most of my facilities, um, anything above a GFR

11:46

of 45 is good to go.

11:48

I think you start getting into this gray range when you're

11:51

about 30, um, or less,

11:53

and that's probably not too much of a stretch.

11:56

Maybe have a conversation

11:57

or have at least, um, some, uh, chronicity of, uh, reduce,

12:02

um, renal function.

12:04

Um, before, you know,

12:06

you start just diving into the contrast.

12:07

Now, how much contrast are we using?

12:09

We'll get into that one there,

12:10

but essentially we're just looking at somewhere around, um,

12:14

60 to 80 milliliters of a 300, um, milligram,

12:19

uh, or a 300 density of an iodinated contrast.

12:25

Okay? Procedural medications.

12:27

This is probably one of the better slides to keep in mind,

12:30

one of them, which is

12:31

because the optimization of heart rate really makes

12:34

or breaks everything, and this is just no matter the expense

12:38

of the scanner, no matter the, uh, technical capability

12:41

of your technicians

12:43

or your nurse, if you cannot get a very good heart rate

12:47

optimization, so 50 to 70, somewhere around there,

12:50

you're gonna have problems in the interpretation

12:52

port portion of it.

12:53

So as this slide indicates, anything around the 60

12:56

or less is probably a good way, you know, good time

12:59

to do, do the acquisition.

13:01

That of course, is a rolling dynamic number.

13:03

It is dynamic as the patient may be sitting in a cold,

13:06

dark room, um,

13:07

and you do a, a, a heart rate optimization evaluation,

13:11

and all of a sudden they're 50, no problem.

13:13

But then as soon as you start walking 'em, getting onto

13:15

that scanner, laying 'em down, it's a brighter room,

13:18

the technician starts talking to them,

13:19

and all of a sudden in our 30 year olds, right,

13:22

that shoots up to about a hundred.

13:24

It's not because you didn't have good heart rate

13:27

optimization and control, it's just that's, you know,

13:30

that's a, a good working and dynamic nervous system.

13:33

So I tend to have a little bit of five milligram,

13:36

maybe 10 milligram of iv, um,

13:39

medication available metoprolol available so

13:42

that if the technician or the nurse is seeing that

13:45

after they gave, um, the, you know,

13:48

after they've taken their optimized heart rate

13:50

and they had it noted that if there still is some, um,

13:54

dynamicism to the heart rate

13:56

and they're able to calm 'em down through breath holds,

13:58

then um, then we can give the IV medication.

14:03

Um, little chat about averdine.

14:05

This is typically done in academic centers.

14:08

This is considered the, the hammer, the sledgehammer to, um,

14:12

help out for individuals who have very consistently

14:16

tachycardic, um, rates.

14:19

Uh, I would say it's probably about 60%.

14:22

Uh, if we do use it, that it, it is successful, um,

14:25

that probably has nothing to do with the medication,

14:29

but more to do that, just a very

14:32

anxious patient is still gonna be an anxious patient

14:35

regardless of the medications you do.

14:36

And that's just their survival instinct.

14:38

So if you find that, um, maybe there's other methodologies,

14:42

but after you've, uh, maxed dose about 300 milligram po

14:46

metoprolol, and then you start on the evine train

14:49

and you're still not getting any results,

14:51

they're still hovering around 70, 65, maybe once

14:54

or twice, then

14:55

that's probably not gonna be the right patient.

14:57

I would probably still elect

14:58

to get then a full retrospective, um, acquisition.

15:04

But, um, some of my colleagues say, Nope, we'll just send it

15:06

to something else to get, um, that, the coronary evaluation

15:09

or chest pain evaluation.

15:11

But I like to scan just so that I can see

15:13

what I can learn from that.

15:14

And typically what we're dealing with in terms

15:17

of a population sensitivity wise is low risk

15:20

or any immediate risk.

15:22

It's not the higher risk where we're dealing with 70,

15:24

you know, to 99% stenosis where we really need a good,

15:28

quiet, slow, you know, um, still study to evaluate.

15:32

Does that make sense so far? Okay, positioning.

15:36

Um, this is typically what we have where, um, IV access

15:40

and then, um, uh,

15:42

and then leads are typically from the right side

15:44

of the patient field of view, obviously

15:47

centered on the chest, um,

15:48

and then leads off to the side in the periphery

15:51

of the chest wall here.

15:52

Typically, um, there's lead one and two,

15:55

and then, um, you know, uh, frontal lead, so above the head,

16:00

IV arms straight, um, ECG lines outside cranial side

16:04

for contrast line, of course, um, their metal items.

16:08

Um, not usually a problem.

16:10

I mean, this is pretty standard for every place, um,

16:12

and for essentially any acquisition of the chest.

16:15

So, um, lots of patients like to have their, um, a bolster

16:19

underneath their legs if they're on the scanner

16:22

for more than five minutes, I would suggest

16:25

changing the routine of your medication optimization.

16:28

Um, typically we have them on the table less than two

16:32

minutes, and that is a, an an area of really great,

16:37

um, uh, performative improvement.

16:39

So quality assurance, uh, assurance

16:42

and quality, uh, sort of quips.

16:45

So where you, if you're spending more than five minutes,

16:47

that's where you take that chunk of that

16:49

of cardiac imaging workflow and, and management

16:51

and you start dialing and figuring out out how that,

16:54

and why that patient's staying on there five minutes.

16:56

Is it because you didn't have two confirmative heart rates

17:01

that are less than or wherever your window is for 60 to 70?

17:05

Is it because you are transporting from a nurse center, um,

17:09

down to the CT center that's too far,

17:12

and then all of a sudden then the IV medication starts to,

17:15

um, dwell off?

17:17

So there are a couple different things that you can work

17:18

with it, but I usually see how long and I ask them,

17:21

and in fact, in some of my outpatient centers,

17:24

I have a little number space there

17:26

where they then are supposed to put in

17:28

how much time they spent on the table.

17:30

Most of them do check in a certain number, you know,

17:33

just try to keep me off their back.

17:35

But, um, I have some that are videotaped so

17:38

that I can just see, you know, exactly how long it's taking.

17:42

Procedural, uh, for the acquisition,

17:45

we typically do a breathe in, breathe out,

17:48

breathe in, hold your breath.

17:50

Some people can do an expiratory, so breathe in,

17:52

breathe out, hold your breath.

17:55

And then others are just a simple tidal volume breath.

17:58

So all three of them are especially acceptable.

18:01

There is no, from what I've seen, one

18:04

that works better than other, I would suggest tailoring it

18:08

in your checklist to the type of patient.

18:11

So if you have a small patient,

18:14

you want more tidal vol, uh, more volume.

18:17

So an ary hold is probably a good thing

18:19

because you want to expand the seat, um, the field of view,

18:23

uh, to make sure

18:24

that your heart is centered right in the center

18:27

of the field of view.

18:29

ISO centered, right? If you have a larger patient maybe

18:32

taking breath in and ex

18:34

and then expiring it out so

18:37

that the heart then is concentrated there,

18:39

that's probably another good way

18:40

of going that Oh, about it too.

18:41

I've also seen small tidal volume, you know, five

18:44

to 10 milliliter tidal volume, and that can work out well.

18:48

You don't need to typically do a val Salva.

18:51

What that does is tends to rush in lower extremity,

18:56

non contrasted volume, um, at the same time

18:58

that your contrasted volume from your right, um,

19:01

upper extremity comes in

19:02

to the right chambers at the same time.

19:05

And most of the, um, uh, generation two,

19:09

2.5 CT scanners, they are fast enough now

19:13

that you actually will see the mixing

19:15

and sometimes the mixing can cause then, um,

19:18

some issues in terms of attenuation and reporting.

19:21

So I don't usually have anybody squeeze, squeeze their butt,

19:25

squeeze their legs to try to pull in all the blood.

19:28

It just never works out that way very well.

19:31

I think tidal volume is fantastic, um, for most places

19:34

that are, for us automatically run working really well.

19:39

In terms of the breath hold time, most of

19:43

scanning is acquired within six seconds, eight seconds.

19:49

Um, the newer ones, um, uh, do spin faster

19:53

or have, you know, a detector, a z detector length

19:55

that is whole heart.

19:57

So you definitely get like one to two seconds

20:00

of acquisition in there.

20:02

So what this means for your patient, really not much

20:06

because the whirl of the, the worrying of the motor, um,

20:09

is occurring at the time of the Topo Graham or the scout.

20:12

It's also occurring, um, at during the feeding.

20:16

So they're not really gonna know the difference on the

20:18

acquisition from the pre-procedural acquisition.

20:22

Um, but your technician only has three seconds

20:26

of acquisition, so it's really affects more

20:28

of your technician in terms of that this is so fast compared

20:32

to five, 10 years ago when we were all in 64 row.

20:36

Now, most of the scanners that I see these days,

20:38

we've gotten, have gotten about 10 years

20:40

of life out of those 64.

20:42

So everything is sort of moving on to the one 20 eights,

20:46

two forties and the omes, um,

20:48

or, um, photon countings, which are faster.

20:51

Um, so, um, I think around five seconds is still the goal

20:56

to tell your technician as well as your patient, that of, of

20:59

how long this is gonna take.

21:00

That's also reassured to them

21:02

that they can just relax a little bit more.

21:05

Contrast media, what is, uh,

21:06

the right amounts in the right time.

21:08

Um, there's a lot of discussions about

21:10

what is the best contrast media, um, while, uh,

21:14

probably three years ago, you and I would also agree the the

21:16

best one is the one that we can get, right?

21:18

Because we did have that contrast shortage.

21:20

Oh man, what a, what a crazy time that was

21:24

trying to find contrast.

21:25

Contrast on the black markets. I mean, all this craziness,

21:28

it was just nuts, right?

21:29

Um, and so what it really allowed us

21:32

to do was dynamically get down to what is important

21:36

and the importance is delivering that small bolus.

21:38

If you've actually looked at it, you can do, we tried this,

21:42

what is the, how low can we go, right?

21:44

Like, how low can we go? It was around 20 to 40.

21:47

If it delivered correctly, it was enough to cover the heart,

21:51

um, but also allow then for some of it,

21:54

which was still just right in the middle

21:55

of the, the IV line.

21:56

So 20 to 40 really is all you need.

21:58

And you guys see this too, right?

22:00

How much of your bolus, your 80

22:02

and uh, maybe 90 milliliter is still in the right, you know,

22:06

AC or traveling through the subc clave at the time

22:09

that acquisition's already occurred, probably half of it.

22:11

So start playing with that

22:12

and how do you deliver that at the time of acquisition,

22:15

but also at the same time have an interval padding,

22:18

you know, as we like to call it in terms of the acquisition,

22:22

but also the contrast in there.

22:24

Anyway, that being said, the concentration

22:27

of iodine should be somewhere, magic number,

22:29

somewhere around 300.

22:30

I think that's really optimal.

22:32

So we have a couple different products,

22:33

Omnipaque 300, we like to use that.

22:36

I think that's a pretty good one. And that's through ge.

22:39

They actually opened up two different facilities

22:41

in two different parts of the world.

22:43

One in their Norway plant.

22:44

They still have that one,

22:46

and that one is still kicking out a ton.

22:48

The problem was, is that the Norway plant had a contract

22:51

to send it to, um, it wasn't Shanghai

22:55

du it was a, a really well-known, you know, um,

23:00

great city in in in China that did very well.

23:03

But unfortunately they were under covid

23:04

restrictions, so they couldn't do any work.

23:06

They actually had to stop.

23:07

So it wasn't the oaring in the, in the, the pre material.

23:11

It was actually the finishing material in China

23:13

that was a problem for our, at least mine,

23:16

US related shortages.

23:17

So GE opened up another one in South America,

23:20

um, for processing.

23:22

Um, so that kind of helped alleviate potential one,

23:26

you know, pathway concerns.

23:28

So that sort of just in time model is now a just in case.

23:32

So I, I don't think we're gonna have iodine concentration

23:37

issues as I'm now like calling the gods to, uh,

23:41

reign contrast on me.

23:44

ICVU is also another one.

23:45

It's, it's a little bit more expensive, um, mainly

23:48

because it can pack in more iodine in there.

23:51

And to be honest, you don't want too much iodine, um,

23:55

in there if you haven't prior to in,

23:58

what I typically do is I get the image right, just like you,

24:01

you can potentially just do a bone window, right?

24:04

So you bone window down, that gives you an opportunity then

24:07

to, it's a little bit higher than bone window,

24:10

but essentially that's a good starting point,

24:11

and then you can go up maybe a little bit more.

24:13

Um, but basically you're getting rid of all the,

24:16

the contrasting that I assume you three 70 gives you.

24:19

So that's why I just, I don't wanna

24:21

pay the premium for that.

24:22

I have too many centers, and then a lot

24:25

of our other vascular work doesn't really do very well

24:28

with three 70.

24:29

Um, so I don't, I'm not a big fan of having

24:34

so many different types of contrasting for one,

24:37

for cardiac one then for neurovascular one, then

24:40

for, you know, body and stuff.

24:41

So, um, I'm gonna pick 300, not that I'm endorsing it

24:45

or I have any shares or anything,

24:46

but that seems to work out very well for our facilities.

24:48

And like I said, they figured out on the backend, uh, how

24:52

to ensure duplicative

24:53

and reiterative, um, safety controls in the

24:57

contrast supply chain.

24:58

So, fun times, right? But I do would wanna foot stomp this.

25:02

I think a a right AC is absolutely, it's the shortest,

25:07

it's the most, um, I would think the safest route to go.

25:11

You do have a little bit of anatomic, um, uh,

25:16

anomalies that can occur with a left SVC,

25:19

maybe the brachiocephalic not being all

25:21

that great it dumping into all these other places

25:23

if you do a left route.

25:24

But I mean, you have to do what you gotta do.

25:26

So, I mean, don't worry,

25:28

but starting out in one place saying like, okay,

25:30

baseline's always gonna be a right ac it's gonna be a 17

25:33

or 18 gauge, or I'm sorry, 18

25:35

or 16 gauge if you're really lucky.

25:37

16 is really great. Um, even that's fantastic on our young,

25:40

um, sorry, our older patients, we have to, you know, try,

25:44

uh, go to a, um, you know, a smaller needle.

25:48

And so unfortunately that gauge will pop up, right?

25:51

And then we're getting down further

25:52

into the lower extremity.

25:54

Um, that's a tough one

25:56

because you want to stay on a baseline in terms of quality,

26:00

in terms of interpretation,

26:02

and then at the start, if you start deviating from that

26:04

or allowing the tech, the nurses to deviate,

26:06

you're gonna get a lot of different acquisitions

26:09

with different attenuations within your coronary arteries.

26:12

So don't, don't try to get too far into, you know,

26:16

cutesy technique with butterflies in the hand, just

26:19

because it's 78-year-old female or anything like that.

26:22

Try to toe the line if you need to get the, uh,

26:26

ultrasound out so you can find the vein

26:27

or colon, you know, the, your, your pick team

26:32

or whatever like that to get it.

26:34

I, I think that's a good way to go.

26:35

Um, but don't try to, you know, just for whatever you need,

26:40

you don't, you know, to get a, a butterfly in there

26:42

and let's roll because the amount of pressures

26:45

that we're gonna be using, which will be in the next

26:46

slide, it's not fun.

26:48

They blow fairy more commonly when they're further down on

26:52

the lower on the upper extremity towards the hands.

26:55

So let's talk a little bit about that contrast volume.

26:58

We sort of hinted upon this a little bit earlier.

27:01

Essentially we're looking for around 60 to a hundred.

27:04

Um, I would say around 40, um, is where I try to be,

27:09

but um, a lot of my autonomous places, they like, um, quats

27:13

of 80, I don't know why I keep telling 'em,

27:15

let's bringing down a little bit smaller to 40.

27:17

We could get more patients with, uh, less contrast

27:21

with this, but 60 to 100, uh, 10 to 12 second duration,

27:25

where if you're doing, um, a different type,

27:27

couple different types of bolus techniques,

27:29

we'll get into that in the next slide.

27:31

Uh, but the rate, so the rate, there's a lot

27:34

of different rate practices out there based on BMI.

27:38

Why? Well, there's a linear sort of correlative

27:41

that the bigger your patient is, the more contrast you need.

27:46

I don't believe that I, I, I think what

27:48

that means is essentially is that we are not, um,

27:51

conning down to the heart.

27:53

Um, and more importantly, we are not timing it critically,

27:58

but essentially if you have a larger patient in the AP

28:02

diameter, if you have more contrast delivered, uh,

28:05

that could be timed correctly within the, the coronary tree,

28:08

then that will help out with the attenuation

28:11

that's gonna occur just because there are a larger portion

28:13

and a lot of the anterior

28:15

and the posterior aspects are going to attenuate.

28:18

And you're gonna get that, um, uh, that modeled look, um,

28:22

that's just sometimes unavoidable with a larger BMI patient.

28:27

So somewhere around the six is my personal, no,

28:30

don't go any lower than that.

28:32

So six to seven milliliters per second.

28:35

And that might seem fast in terms of, um, what is,

28:39

what do we use in other places?

28:40

So if you're gonna do, um, abdomen pelvis work,

28:43

if you're gonna do, um, neurovascular, it's usually

28:46

around four, right?

28:47

I mean, three to four, you know,

28:49

a nice kind of gentle sort of thing.

28:51

Mr. For instance, uh, cardiac MR usually is two to,

28:54

you know, two to three.

28:55

That's a different substance of course, right?

28:57

Um, but that's in terms of the rate,

28:59

it's the same gauge needle, but we're packing quickly.

29:03

And why, because we're trying to get this all in the fastest

29:08

velocity tube in the entire body, which I would suggest is,

29:13

well, it's probably the second.

29:14

I think your renal vascular bed is probably your first,

29:16

but you can just get the entire thing

29:18

'cause it's a smaller bed, but the corners is must deliver

29:22

very quickly, everything else to the thoracic aorta.

29:24

And so then you gotta hit it fast.

29:27

You can't allow a slow train to go there.

29:30

Or else the, the non pass, non pacified contract, uh,

29:33

blood will be mixed within there

29:35

and it's gonna be a really crappy exam.

29:37

So around six to seven at milliliters per second,

29:40

um, is about right.

29:42

I think you can try to make it faster if you have a bigger

29:46

patient only to try that maybe once or twice.

29:49

I'll be honest, it was never very successful for me.

29:52

Um, but I do like younger patients with that fast flow

29:56

and mainly because, uh, younger patients tend

30:00

to Val Salva a little bit more.

30:01

They take that, you know, breath thing there,

30:03

and then all of a sudden, um,

30:05

the lower extremity mixes in within there if

30:07

you have a longer train.

30:08

So if you have a lot of contrast, 80 milliliter

30:11

for instance, and a longer train,

30:14

five milliliter per second, God forbid,

30:16

four milliliter per second,

30:18

and a younger patient where they're valve saling,

30:20

all the lower extremity in there,

30:22

it's gonna be a suboptimal examination.

30:24

Your attenuation in your

30:26

thoracic aorta is gonna be like 200.

30:29

It's gonna be terrible. In fact,

30:30

you might get a better PE than, um, a good, uh,

30:33

coronary vascular, uh, evaluation if you do it that way.

30:40

So that's one of the things that, um,

30:42

I think is really important to kind of keep an eye on here.

30:45

So let's go through some of these other things here.

30:47

Um, start the scan after contrast diminishing.

30:50

When do you know it? There's two different methods

30:52

of course we've got, uh,

30:53

which is called the bolus tracking technique.

30:56

I don't think anybody's still doing that.

30:57

If you guys are still doing it.

30:58

It's a, there are some really great literature on why it

31:02

works so well because you've tested,

31:04

so known is known, right?

31:06

You've tested it and you've seen it,

31:07

and so then you can model against it.

31:09

Things we know with dynamically with the heart, the patient,

31:12

and then just the next go round.

31:14

That may not always be the case.

31:16

So it's actually not gonna be the same curve.

31:18

It's gonna be maybe shift a little bit more

31:20

earlier or a little bit later.

31:21

So, bolus tracking, we don't do in any

31:24

of my facility centers, academic centers anymore.

31:27

We actually just do test bolusing.

31:28

And so the test bolusing is where it's a small scout of the,

31:32

um, of the area of interest.

31:34

And then typically an ROI is placed, um, in, if you were

31:38

to take this image here and divide into quadrants,

31:41

it's usually into this upper right, uh, left quadrant here.

31:44

Uh, radiology left around here.

31:46

If you get it too close to this side here,

31:47

it could hit a lot of this low attenuating fat around here,

31:50

or, or maybe the AZA is vein.

31:52

Um, so somewhere around here,

31:54

and it should be about two thirds of the size, your circle

31:57

of your, um, descending thoracic aorta.

32:00

This will give you, um, an opportunity to test bolus, uh,

32:04

where your threshold is set at a hundred

32:06

to 120 household unit.

32:08

That's really the best space in the best time to kind of,

32:12

um, then, um, start the contrast.

32:14

The movement through there. Typically the, um, acquisition

32:18

of your test bolus to then the acquisition of the image is

32:21

around two to four seconds.

32:23

That's the hold your breath period of it.

32:25

And so then that's where, um, usually then the, uh,

32:29

the attenuation will increase

32:31

from whatever threshold you set.

32:33

100, in this case, one 50 was, um, was

32:36

where the acquisition began.

32:37

So somewhere around one 20 was where the testing said,

32:40

this is what I'm gonna tell you at.

32:41

And it's gonna continue to, um, increase in a density within

32:46

that descending thoracic aorta, which if you know,

32:49

the coronary arteries is reperfused diastolic, um,

32:53

from the descending thoracic aorta flow.

32:55

So if the descending thoracic aorta flow is at 200

33:00

to two 50 household unit,

33:01

your coronary arteries are gonna be, uh,

33:04

very well attenuated.

33:05

They're gonna be just fine in terms of the attenuation

33:08

as opposed to if you do the ascending thoracic aorta,

33:12

this has not had time to, um, potentially

33:16

meet the maximal amount of, uh, attenuation here.

33:21

So this could be a little too early.

33:23

So I don't, and nobody should be putting an ROI in the US

33:27

sending thoracic aorta.

33:29

I can't think of any good reason why you would

33:31

put it in the US sending thoracic aorta.

33:34

That's of course a good place for neurovascular, right?

33:37

If we want, um, you know, circo of Willis

33:38

and carotid, typically we place it on there.

33:41

If we're gonna do our CTA head neck runs, we put it on the,

33:44

on on right in that space there.

33:46

But really it's this, um, uh,

33:49

I gotta think about that one for a bit.

33:51

I don't think that there's anything,

33:52

or maybe a coarctation, uh, maybe, I don't know.

33:56

Probably not. Okay.

33:58

What is the right injection rate and the right delay matter?

34:02

Um, so optimal signal to noise ratio requires

34:05

that there's an opacification difference, right?

34:07

If we're gonna review this image

34:08

or the one on the, on this side here, we want to be able to

34:12

contrast look at what's inside the coronary vessel

34:16

as opposed to what's outside the coronary vessel.

34:19

And in this case here, we have at least 250 household unit

34:22

in the proximal RCA, uh, whereas this yes, is probably is

34:27

a pacified to around 200 maybe,

34:30

but as you can see here, it's just poor contrasting

34:34

to the remainder of the structures around here.

34:36

And so that's gonna be obviously a, a very difficult thing

34:39

to, to interpret.

34:41

Not that you couldn't, but of course, okay. Right.

34:43

Settings for the highest image quality,

34:45

lowest radiation dose, the elara, uh, methodology here.

34:49

So there are a couple different things.

34:50

This is, um, a, a slide meant

34:53

to show you all the complexities involved in it,

34:56

but we really don't need to involve ourselves

34:58

behind all a lot of this stuff.

35:01

A lot of the preset conditions

35:03

that you will find in your Siemens, uh, your GE

35:07

or your Canon, um,

35:09

equipment will have them designed specifically

35:13

to the optimized capabilities of that, um,

35:17

um, piece of equipment.

35:18

So you won't really need to change it too much.

35:20

What you will need to do is try to determine what do you do

35:24

for your, just in cases, about 60 to 70%

35:28

of your patients will fall in into the presets

35:31

that are available on your machine.

35:33

That's totally fine. You wanna do prospective?

35:35

Well, about 60 to 70% of them should fall neatly within

35:39

that prospective capability.

35:40

It's when, what do we do for the big patient?

35:43

What do we do for the really tiny patient?

35:45

What do we do with the patient that's in an academic center

35:47

and then has a ton of comorbid disease?

35:50

Well, that's where then we have

35:51

to get a little bit more creative.

35:52

We have to learn other techniques, other ways

35:54

of doing things such as, um, how do we play with the pitch?

35:58

How do we, uh, determine then, um,

36:01

the gating are we gonna do Then some type of, um,

36:04

combination like the force allows you to where you have, um,

36:08

or, um, um, you know, where there is that fast moat

36:13

where you can do then a little bit, uh, in,

36:16

in one methodology, but then switch to another.

36:18

And then how do we potentially cover our butt so

36:21

that we have a good data set to review?

36:23

And that's then of course the padding and so forth.

36:26

Image recon, um, we'll get into that just a little bit.

36:28

So here are some scanner, um, recommended

36:34

scan ranges and some protocols here.

36:37

Don't need to take pictures, don't worry about it.

36:39

I'm sure your, your presets already have this on here,

36:42

but one thing to kind of keep in mind here is

36:45

as you start looking along here, there really isn't that,

36:48

well, okay, so maybe the,

36:50

and these need to be updated a little bit more

36:52

because we're probably a little

36:53

bit higher than that right now.

36:55

But the Z axis coverage is essentially the big

36:57

one that we want to do.

36:58

And as you can tell, scan range to z axis coverage,

37:01

essentially one heart, right?

37:03

So those, um, do try to offer that there.

37:05

Um, there are some very nice machines that Siemens have

37:08

that are not, um, dual source.

37:11

They are, um, they're a little bit less than that

37:14

and they do very nice temporal resolution in ranges here,

37:17

but this is a little bit in terms of field of ra, field

37:19

of view, uh, Z axis coverage and scan range.

37:24

Alright, a little bit more into the physics portions of it.

37:26

Here you have a source that provides the radiation

37:30

to then the, um, typically 180, um, offset,

37:35

which is the detector array.

37:37

And that's a array, um, in a, in a way that will cover, um,

37:41

the fanning of the, um, heterogeneous spray of radiation

37:45

that comes through there in the center, uh,

37:47

between the source and detector is typically the patient.

37:50

And so this is rotating in the 360.

37:52

Uh, obviously if you have a dual source,

37:54

the 180 degree is then halved,

37:57

where you then have another source offset

37:59

90 degrees to this.

38:01

So it will then do, um,

38:03

or able to acquire the image data set in half the time

38:08

because it has to rotate only half 90 degree

38:11

instead of 180 degree.

38:14

As we look at this, um, tracing here, this EKG tracing here,

38:18

we have a QRS complex.

38:21

And if we were to take this, this portion here, this r

38:24

to then this next r this is considered the cardiac cycle.

38:28

You can divide this up into percentages, zero to 100%,

38:31

or you can divide it up in milliseconds, zero

38:35

to 1000 milliseconds.

38:36

Those nicely coincide with systole.

38:39

So anything 50% or 500 milliseconds and less,

38:43

and then diastole 501 to then,

38:46

or 51% to then 100%.

38:49

And so the acquisition will tend to occur in the area

38:52

that is best optimized for the coronary artery in terms

38:55

of opacification heart rate optimization,

38:59

where there's less movement due to the squeeze

39:03

or the systolic movement of not only just the valves,

39:06

but also the chambers as well.

39:07

So you get less valvular movement,

39:09

less chamber movement in when sary, diastole diastole.

39:14

So typically a lot of the presets

39:17

and protocols are in diastole, mainly

39:20

because that's where less of the move motion

39:22

and movement is

39:23

occurring in the dual source.

39:28

As I mentioned here, we have a 95 90 degree offset,

39:31

so they're able to acquire that in half the time.

39:37

Okay? Uh, rotation.

39:41

Rotation has to synonymously deal

39:44

with temporal resolution.

39:46

So we have spatial resolution, which is associated with

39:50

how many detectors are on the, on from source to detector,

39:55

how many detectors do you have in there,

39:57

and what kind of septation is in there

39:59

or not, depending if you have a photon

40:01

counter that's spatial.

40:03

So how much can you acquire in the radiation

40:07

that's being spt spat out there.

40:09

Temporal resolution is how quickly

40:13

is the source moving to acquire it?

40:17

So what is the highest temporal resolution imaging

40:20

modality that we have?

40:22

Is it nukes? Is it mr?

40:25

Is it x-ray, what do you guys think?

40:28

Ultrasound it's What do you think?

40:32

And this will be probably one

40:33

of the only questions I'll ask you guys.

40:38

Any thoughts? Do you think it's CT is

40:42

166 milliseconds the highest

40:45

and best temporal resolution in imaging?

40:48

No, ultrasound probably is considered, uh, one

40:52

of the highest diagnostics for cardiac imaging, mainly

40:56

because it's essentially a motion

40:58

or a view of what's occurring there.

41:01

Now, the spatial resolution is not what CT imaging is like,

41:06

hence why it's had, has a very limited degree

41:09

of use in cardiac imaging.

41:11

But the temporal resolution, how,

41:14

and you can see something move in time

41:16

as you're seeing my hand move, that is

41:19

where ultrasound shines

41:20

and why then we try to optimize that in CT in terms

41:24

of evaluating for temporal resolution.

41:27

So how do we get higher temporal resolution, reducing

41:31

the amount of spin necessary for the source to complete

41:35

that a hundred, that 180 degree or 360 rotation.

41:39

So if you have two sources instead of one source,

41:42

your temporal resolution's gonna go down.

41:45

If you have more detectors

41:47

or a longer paddle of detectors,

41:49

that could make your spatial resolution go down.

41:56

Okay? So the recommended pitch, this is

41:59

how quickly you move in the Z axis from, uh, for instance,

42:03

from the top to the bottom or my diaphragms up.

42:06

So, um, most coronaries have a very flashed

42:09

or high pitch, um, with if you're gonna do this dual source.

42:13

Um, but for the most part,

42:14

the recommended pitch is somewhere

42:16

around just a little under one in why that is, is

42:20

because we want to over sample an area, have more data

42:25

so that we can then ensure that there is, um, less motion

42:29

or gaps in the evaluation.

42:32

So if we're covering a large area such

42:35

as the abdominal aorta, thoracic aorta,

42:38

we have a high pitch, fast pitch, right?

42:40

That's where, um, those really shine

42:42

because there isn't a lot of variability in one centimeter

42:47

to the next centimeter in terms of the abdominal ATA aorta,

42:50

for instance, or the carotid arteries.

42:52

However, in coronary the real estate is smaller

42:57

and so there is much more variability in one centimeter.

43:00

And so therefore you want to unders sample

43:02

or to have a smaller degree of motion along the Z axis,

43:06

obviously you need the motion to move it there

43:09

or you aren't gonna get from point A to point B,

43:11

but it's extremely important.

43:13

So perspective gating,

43:14

what this means is if we were gonna take a look at the

43:17

sample volume here, we're going to evaluate six to 80% of,

43:21

um, that cardiac cycle, which I told you was a,

43:24

the diastole, the, um, table's going to x-ray on 40

43:29

for about 40 millimeters,

43:30

and then we're gonna then move the table X-ray on

43:33

for the next 40 millimeters and then move the table

43:36

and then x-ray on on so

43:38

that we could cover the stack from the bottom of the heart

43:41

to the top of the heart

43:42

or the top of the heart to the bottom.

43:45

This is called the step and shoot

43:48

or axial methodology as opposed to,

43:52

uh, CT chest.

43:54

Very interesting, right? So we have two organs

43:56

that are in the same cavity, uh, let's say the lungs

43:59

and the, and the heart, but the helical

44:02

or spiral acquisition is not useful at all for cardiac, not

44:06

because of of other reasons, but mainly

44:10

because we're just not getting that fine spatial resolution

44:14

that, uh, will be extremely useful.

44:16

Um, so it was very interesting

44:18

because for a lot of of time the cardiac ct, um,

44:23

coding was in the same basket

44:28

as the pulmonary or lung evaluation

44:31

because it was assumed that the technique was the same.

44:34

Now, of course, there was obviously a lot more in cardiac

44:37

imaging, coronary cardiac imaging than, uh,

44:40

a pulmonary angiogram of the chest, uh, for the lungs,

44:44

for instance, or for, um, the thoracic aorta.

44:47

So it actually is not the same, um, and should

44:50

and rightfully so, has been in, in my country, been moved

44:53

to a different separate coating, um,

44:55

because it does involve a separate different technique.

44:58

So that was actually a really good win, um, to kind

45:01

of help people understand that retrospective instead

45:04

of the stop shoot, we just have the, um,

45:07

source on all of the time.

45:09

And you can see that it's just acquiring

45:11

a 100% source on acquisition, a dataset, um,

45:15

from the, um, bottom of the heart to the top of the heart

45:18

or the top of the heart to the bottom high pitch.

45:21

Um, essentially it just has, um, you know, that pitch.

45:24

So there is less duplicative sampling

45:27

and more of motion, um, potentially prone.

45:31

Now we like to do this in, um, again, vascular imaging.

45:35

So if you're gonna do a thoracic aorta evaluation

45:37

for aneurysm or post tvar, um, plus your coronary arteries,

45:42

you want to do one that's the coronary artery technique

45:45

first retrospective, get the entire data set

45:47

and then do a flash technique while the contrast is still

45:50

there to acquire the, the thoracic ata.

45:52

Of course, you'll capture the thora, uh,

45:54

the coronary arteries one more time,

45:56

but it will then allow you then to capture that amount

45:59

of real estate at a smaller spatial resolution comparatively

46:03

to the coronary arteries.

46:05

So that's just a typical, uh, TAVR technique, right?

46:09

Padding. You might have heard this term,

46:11

and I'm only talking very quickly about it,

46:14

but we can get into a little bit more.

46:16

It's where there is just a little bit of fluff.

46:18

The tube is on 100%,

46:19

but there tube could be on a little bit more, uh, on,

46:23

but at a less so maybe 90%, 50%, 25% in terms

46:27

of the, of the, uh, amount of, of dosing,

46:32

but at different parts of it.

46:33

So a little bit before and a little bit

46:34

after your main acquisition.

46:36

Why is that useful? Well,

46:38

you can still iteratively reconstruct some of

46:40

that imaging into your, um,

46:43

what we call an idealized dataset

46:46

to get you a good looking coronary tree.

46:50

It's interesting because it's actually, um,

46:52

using the same coronary arteries,

46:54

but a picture is not the same picture as another picture

46:58

of the same thing, right?

47:00

So if I were to take a picture of, um, you know, this tree

47:03

behind me here and I take it one time

47:05

and then I take it another time,

47:06

those are two separate pictures,

47:08

but I'm gonna fuse 'em together of the tree.

47:11

And that's supposed to be a good representation

47:13

or a finalized representation of the tree,

47:15

but it actually is two separate pictures of the tree.

47:19

So you can get superimposed artifact, you can get modeling,

47:23

or you can get an over

47:25

aggressive re iterative reconstruction.

47:28

I only make that up because you may want to,

47:31

as you're deciding to create a program,

47:32

look at the raw imaging.

47:34

It's a big dirty data set, but it's a thin, you know, 0.25

47:39

and then see what you like,

47:41

how much iterative reconstruction, how much, um, you know,

47:44

filter back versus the iterative,

47:46

you know, do you want in there?

47:47

And you can play with that. How thin, thick,

47:50

how much padding, not so much padding do you want involved

47:53

to be sent to you for the acquisition.

47:55

Now, me, I try to use,

47:59

uh, the least amount of acquisition, the least amount

48:03

of images sent to me.

48:05

I believe that just hones my clinical skill as opposed

48:09

to having a ton of data sets, a ton

48:12

of imaging, and to go through it all.

48:14

Um, not only is there an efficiency standpoint,

48:16

but also it allows me then to say, look, I need

48:20

to change some things in my protocol to ensure

48:23

that this type of patient with this thing, I don't,

48:26

I I get the best thing next time.

48:29

So how do you become better?

48:31

I don't know if it is because you have more tools

48:34

or that you constrain your tool set

48:37

and try to hone to the areas of, um,

48:40

where you can optimize it.

48:42

So for me, I don't have a lot of padding.

48:44

I know that my cardiologist who work with me,

48:46

they love a lot of padding, um, but it's less work.

48:50

It is more efficient, um, sending it,

48:53

receiving it across different areas of the country.

48:56

In my country anyway, it's prone to less error.

48:59

And, um, I think it's a good way of, like I said,

49:02

honing my own personal technique.

49:03

I don't know what you guys think about that,

49:05

but this is one of the ways that we can use

49:09

to make more images that might be good

49:12

or not good depending on where you want to be in terms

49:14

of a cardiac imager.

49:19

Okay. Field of you. And, uh, we'll stop here

49:22

for a little bit just so I can ask, uh, uh,

49:25

get some questions from you guys.

49:26

Again, this PowerPoint extensive so much a lot in here,

49:32

um, and I'm hoping when we go to office hours that, uh,

49:36

you have some more questions about this based on, you know,

49:39

not only the interpretation,

49:40

but also then some of these things, protocols and factors,

49:44

but field of view, the matrix

49:46

and spatial resolution are correlative.

49:48

So, um, how big you make your matrix

49:52

will have an inverse relationship to the spatial resolution.

49:56

So you make a really large matrix

49:58

that then could potentially invert the,

50:00

your spatial resolution

50:01

because obviously you have to fill that data

50:04

with the limited amount

50:05

of photons we're going through there.

50:06

So if you constrain your matrix size, um,

50:09

five 12 is typically what we keep it at

50:12

and you constrain your field of view, that amount

50:16

of photons in will

50:17

and displayed in your matrix, your, your visual matrix

50:22

will then be at a better ratio as opposed to then, um,

50:26

doing, uh, the opposite.

50:28

So what I try to do is I try to tell my technicians,

50:30

make the smallest box possible, smallest box possible.

50:34

I need the coronary arteries, you know,

50:36

and that's there in the larger, the extra coronary.

50:40

What we have to do for atypical coronary CTA, that's

50:43

where you go from shoulder to shoulder,

50:45

but my coronary view should just be the coronaries.

50:48

It's not even the rest of the heart

50:51

and honestly it's just the coronaries

50:52

because I'm dealing with a limited amount of, of radiation

50:56

that I want to put into the coronary arteries as opposed

50:59

to the extra coronary, um, organs of the body.

51:03

So in this case here we have a very high spatial resolution

51:07

due to the constrained voxels, um,

51:10

and, uh, voxel, uh, uh, matrix here, the two 50

51:14

by 2 55 12,

51:16

and as you can see here, it can be difficult to always, um,

51:20

artistically change this on every patient.

51:23

So make sure that you have a sized box based upon typical

51:27

anatomy markers.

51:29

So the anatomy marker that we typically do is the anterior

51:32

aspect of the sternum, as you can see here,

51:34

and the first third of the vertebral body

51:37

that typically gets the, uh, thoracic aorta,

51:40

descending thoracic aorta

51:41

and the ascending thoracic aorta, which will always be

51:45

the coronary arteries, will always be bounded

51:47

by those two structures anterior

51:49

and the descending thoracic aorta.

51:50

Never knock on wood,

51:52

have I ever seen the coronary arteries extend

51:54

beyond the field of view of those two structures there.

51:56

Um, just wait until the next exam I guess. Okay.

52:01

Alright, so iterative reconstruction and quality.

52:04

This has always been a hot topic for many,

52:06

many years, decades, right?

52:08

You and I have always gone back FVP, uh,

52:11

how much acer admire do we want on these?

52:13

And we get to play with that and look at it.

52:15

Some guys love it, some gals don't, da da on

52:19

and on it, it's personal preference

52:21

because this is just the image interpretation standpoint.

52:24

It's not the image acquisition.

52:26

So you can always change it, change it within two weeks,

52:29

because sometimes you,

52:30

you get the data dump on your CT scanner, right?

52:32

But, um, but anyway, I'll, I'll leave that up

52:35

for another thing because there's some really fun things

52:37

that AI is doing

52:38

where you can actually reduce your dose down to, I've seen,

52:42

I work with some companies,

52:43

they're like down at like 25, 30 milli seaberg, you know,

52:47

really tiny amounts, like a third of current dose.

52:50

I'm about a hundred, 105 most in most

52:52

of my centers right now, but they're at 25 30

52:55

and they're AI based iterative reconstructions,

52:58

and they look just like the, the normal ones,

53:00

the diagnostic ones, they're fantastic.

53:03

And it's not just in your Joe Schmo

53:05

idealized patient, right?

53:06

I mean, it's like big old chunky dudes, you know, and, and,

53:10

and so forth and calcified, you know, coronary arteries,

53:13

like these are legit coronary disease patients.

53:16

So, um, it's kind of fun to see that stuff

53:18

that AI is constantly improving this area of it.

53:21

It's never gonna take away us yet,

53:24

but I think it's doing some really great stuff in terms of

53:26

that soft kernel, sharp kernels.

53:28

There are some importance of utilizing

53:30

or having the opportunity

53:32

or at least knowing when would I use a soft kernel?

53:34

That's when I want to have more gray

53:37

and open up than that spatial resolution a little bit more.

53:40

Um, sharp kernel is where there is a contrasting difference

53:45

between the edge of the coronary artery

53:47

and the next thing around it.

53:48

So the fat. So if you have calcium for instance,

53:50

or if you have stents, you're gonna use a sharp kernel.

53:53

What's another name for a sharp kernel long window?

53:56

What's another name for maybe a soft kernel?

53:58

Probably, you know, a body window or a bone window.

54:05

Okay, so I'm gonna stop right there just so that I can kind

54:08

of show you a few of the other do, do, do.

54:12

We're gonna share. Hmm,

54:17

where's the screen?

54:18

Okay, very quickly, I, I think you all had gotten a, a quick

54:23

tutorial on Terry recon,

54:25

maybe you've visited in the past or not.

54:27

Um, the way that I, I've known it

54:30

for a very long time, I think it's fantastic.

54:33

We, um, all the cases will have a week one and a case one.

54:37

There'll be five cases per week, um, like I said, try

54:40

to do one per day just so you get used to the program just

54:44

so there aren't any issues,

54:45

but essentially have it outlined here.

54:47

Um, you may have then, um, you know, a little window,

54:51

a visualization window that will then show down here

54:54

where you can scroll through as well.

54:56

But, um, these were typically acquired on a Siemens.

55:01

So this is Siemens, no nomen, uh, nomenclature here.

55:05

So, um, the 55 obviously means that, uh, heart rate,

55:10

cardiac cycle, it was considered the best diastole.

55:13

And you can see then that's probably somewhere right around,

55:15

although this image says 70, um, it's,

55:18

it's probably more true to 55.

55:20

Okay, so I'm going to click then on the load button here,

55:24

I'm gonna find this is anatomically.

55:26

So the top of this row is for neuro neck

55:29

and then we get into cardiac pulmonary, um,

55:32

abdominal, mss, K and so forth.

55:34

So we're gonna find a coronary, uh, cardiac one here.

55:37

You can do cardiac cardiac one, cardiac tech.

55:40

It's all it does is as we move from patient list

55:43

to then the viewer and back

55:45

and forth, all it did was rearrange these mini apps here.

55:48

So, uh, as you can see here, this uh, has your, um,

55:54

axial, coronal and sagittal view,

55:55

and then it also has then a 3D, uh, volume rendered.

55:59

The chest wallet is in there.

56:00

If it didn't automatically remove it,

56:02

you can click this button here to remove it.

56:05

And so then now you have your volume rendering.

56:07

The volume rendering is not usually designed

56:10

for a diagnostic or interpretation,

56:11

but it is a good idea to see then,

56:13

because this is based on contrast, how

56:17

well contrasted is the LAD

56:19

and all its, um, branches here to, uh, to the RCA, uh,

56:23

to the, I'm sorry, to the LCX and then to the RCA.

56:26

Uh, and so, um, I'm sorry, so that's LCX

56:29

and that's RCA down in that area right around there.

56:32

So how do they look? Are they isometric, iso attenuating?

56:35

Do they have, you know, a pretty good look view?

56:37

You can remove, um, you know, some of that tissue

56:40

by holding down your left and right mouse

56:42

and that essentially windows and levels it off.

56:45

Um, as we're kind of doing some work here, um,

56:48

I'll show you this row is the volume renderings Uh,

56:52

so it'll just move them accordingly.

56:54

Here. Let's go ahead and just take this right corner artery.

56:57

I'm gonna click the shift button.

57:00

And as you can see, that should,

57:02

uh, no.

57:06

Oops. Okay. Yeah. So once you're on this row here,

57:08

if you hold down the shift button, you've got a cross hair,

57:11

you can see the cross hair, then you can click on the

57:13

coronary artery and it'll just then do a full width half max

57:17

on the attenuation of there,

57:19

and then, um, be able to show you that, uh,

57:21

from the origin all the way down to the, the tail.

57:25

These are 90 degrees to each other.

57:26

So once you turn this one, this one will turn you,

57:29

you've got these handlebars here

57:30

that can then help you measure

57:32

then the length of the plaque.

57:33

There is of course, a, uh, an A to B ratio,

57:37

which can give you a, a percentage ratio.

57:40

Um, that's kind of important. Down here is the SMPR.

57:44

So straight, um, multiplanar reformat,

57:47

and so you can straighten it.

57:49

Now, what is the highest spatial resolution?

57:52

The highest spatial resolution is the one that is,

57:54

looks like, acts like the one that, um,

57:59

that is similar to what was acquired.

58:03

So if your patient's laying on their back

58:06

and we're actually acquiring,

58:07

the highest spatial resolution image is gonna be

58:10

that the done your axial acquisition.

58:13

So this will have always, always, always, always

58:17

the highest spatial resolution comparatively

58:21

to your volume rendering, comparatively to your

58:25

CPRS curved plan reforms or your straightened plan reforms.

58:28

So what I'm saying is the more that you have to take

58:32

this amount of data

58:33

and three dimensionally place it into this, and then this

58:37

and this, you corrupt the data.

58:39

That is, it becomes, as you can tell,

58:42

less spatial resolution compared to this.

58:45

So this should not be your go-to,

58:47

or your first wave interpreting.

58:48

This is your real estate view.

58:50

You are looking at this to see what are the areas

58:53

of concern, what are the areas of interest?

58:56

And so if we're evaluating from the origin its course

59:00

and its termination,

59:02

and then what is inside here, attenuation wise,

59:05

we are making sure that it has a normal origin,

59:08

a normal course for this particular artery,

59:10

for the atrial ventricular groove,

59:12

and the posterior inter ventricular groove

59:14

and terminates deeply in the, um, posterior aspect

59:18

of the chambers.

59:20

And then of course, attenuation is the same,

59:22

and there's no luminal blockage running along in there.

59:25

These will give you less information compared to this.

59:29

Now, what this gives you is real estate view.

59:31

You can see the entire thing,

59:32

whereas this is the higher spatial resolution.

59:35

So we will find more information if we follow this

59:38

guy all the way down.

59:40

It's actually faster to read it axial off your PACS than it

59:44

is to try to, you know, speed this thing up, turn it on,

59:48

forget your password, reenter a password, find a patient,

59:51

oh no, images are not there yet.

59:53

Upload the images again,

59:54

and then come in here and then do this.

59:57

Whereas if you were to learn how to read from your,

60:00

from your packs, it's better and easier.

60:02

So I personally read a axial.

60:05

I of course have access to the these

60:08

and have it for just, you know, di some

60:10

of the difficult cases where I really need

60:11

to make sure my 70 to 99% is correct,

60:15

and how much, um, iso attenuation is there, is there any

60:20

abnormal hypo enhancement of the myocardium?

60:22

Because obviously we're de delivering

60:24

iodine to the myocardium.

60:26

So if there's areas that are hyperintense

60:28

or hyperintense, I wanna make sure I see that and so forth,

60:30

and as well as some of the other structures there.

60:32

Okay. So that is a little bit about, um, this, I, um,

60:37

as you can tell, there's so much more I could go into

60:39

and I'd love to, but we're gonna stop right there, um,

60:43

and, uh, open up for any questions that you may have about,

60:48

um, again, acquisition and protocol design.

60:55

Hi, I have a question.

60:57

Uh, Dr. Lawrence, can you hear me?

61:02

I can hear you. Can You hear me? Yeah. Okay.

61:04

Um, so you said to, uh, look at the aal,

61:08

but we were told yesterday that

61:10

because coronary angiogram, you're supposed

61:12

to assess it in the longitudinal

61:14

because it's different from like carotid a**l.

61:18

Um, so you will still do your recon to a,

61:23

to, if you see a stenosis, you're still elongated

61:27

and measure, right?

61:29

Right. You have to because that's, that's the goal standard.

61:32

That's what he said yesterday.

61:34

No, there are many, many different ways

61:38

of evaluating this.

61:39

What is important is ensuring the accuracy of it.

61:43

And so we're gonna teach you probably three different ways

61:46

of evaluating it.

61:47

And so if you look on here,

61:48

the first row is your volume rendering, which gives you

61:50

that quick view.

61:52

The second row is the curve planar view,

61:56

which like you said, is gonna not gonna be a long axis,

61:59

or allow you then to evaluate the,

62:03

if you were looked down the barrel, the of the circle

62:05

and see then how much percentage stenosis.

62:08

But it does give you a quick view

62:09

because you can have your, uh, line right here,

62:12

and I'm just gonna, and if that's 50%,

62:14

then there's probably less than that.

62:16

That's probably less than 50%.

62:17

And then I'll give you a, a quick view.

62:19

When we go to something, for instance, on this view,

62:22

this is called a vessel track or short access view.

62:25

You can then very quickly see then by circle wise, if

62:28

that amount of luminal stenosis

62:30

or plaque is at 50%, so forth and so on.

62:35

What you forget, though,

62:36

or what my, some of my colleagues

62:37

who teach this forget though, is

62:39

that this double iterative acquisition takes the same amount

62:43

of information on the axial view,

62:45

and it has to duplicate it into this view.

62:48

So as you can tell, it's blurry, it's probably less

62:53

accurate because then, um, you are trying to take

62:56

that same amount of dosing

62:57

and then apply it into a three dimensional view.

63:00

Now, because this is now x, y,

63:02

and Z axis, as we can see here, if you do this on the, um,

63:07

on your packs, by having this view here, uh, this,

63:12

uh, let's skip back over here.

63:17

Your axial, your coronal and your sagittal,

63:20

and then you start playing, for instance,

63:22

with these handle bars here.

63:24

So then you're always looking at down the barrel,

63:27

as you can see here, I'm at, you know, that,

63:29

that's fine too, but what do we know as being radiologists

63:32

or individuals who've been practicing image

63:34

before the coronals and the sagittals

63:38

or the obliques are less information

63:41

because they're not acquired in the way

63:43

because it wasn't the axle, which is the acquisition.

63:46

So even if we are gonna do our short access and da da

63:48

and follow it down there, it's still less information

63:51

because it's not a three dimensional acquisition,

63:53

it's a two dimensional acquisition.

63:55

And so I think that's important.

63:58

It is gold standard,

63:59

but know then that what is considered the gold standard is

64:02

because it was based on inter invasive coronary angiography,

64:05

not CT acquisition,

64:07

which is a two dimensional acquisition as opposed to a three.

64:10

So that's how we, um, work with those,

64:13

those diametric things.

64:15

Coming back to what you said

64:16

and what, um, what I would said earlier,

64:19

we're gonna teach you how

64:20

to take a look at all these different ways

64:23

of interpreting it in, um, our office hour session.

64:27

So you can see the benefit of on pacs two dimensional axial,

64:32

um, on performative, uh, software, so that you can see two,

64:37

uh, two dimensional plus

64:39

and three dimensional plus, which is the short access view.

64:41

So hopefully that answers your question. Thank you.

64:46

Yeah, of course. But uh, as you can see, yeah,

64:49

this thing has all those easily to go to.

64:52

So if you had this already up, many

64:54

of my cardiology colleagues like to only read on here,

64:57

mainly because it doesn't show the rest of the chest.

65:00

But if it's a chest pain,

65:01

you gotta see the chest and everything else.

65:03

And much of our reporting

65:05

that you're gonna be doing in coronary

65:07

and for this course is gonna say, whoa,

65:08

what about all these other structures here?

65:10

Did you look at them? Because we got a lot

65:12

of Easter eggs, um, in there too.

65:14

So something to keep in mind.

65:19

What other questions do you guys have? Does it seem onerous?

65:23

A lot of work? It's, does it seem like

65:24

totally within your wheelhouse?

65:34

Hi, Dr. Lawrence. I had a question.

65:36

Um, I know that you mentioned, uh,

65:38

the glomerular filtration rate, uh,

65:41

but is there a creatinine level

65:44

that you would recommend in order to do the, the study?

65:50

Most of the academic facilities that I work at, um,

65:53

trying not to use a creatinine

65:55

because the, um,

65:59

blood volume plays a big role in creatinine levels

66:02

as opposed to filtration rate, which is, uh,

66:05

although it's, it's not an abs uh, an objective, it is, uh,

66:10

an inferred reference to glial function,

66:13

but I would say somewhere around 1.3

66:15

and less is totally fine if as long as it's full, you know,

66:20

uh, creatinine will increase, uh,

66:23

again based on that blood volume status.

66:25

So typically our older patients will have less blood volume

66:28

and so therefore the will creep up.

66:30

And so, um, I don't try to worry too much about that in some

66:35

of our standing facilities, our imaging centers that I stat,

66:39

um, GFR, uh, is, is pretty good and it works really well

66:43

and I've seen that used,

66:44

but I'd say 1.3 for creatinine, GFR somewhere around 35,

66:49

um, you know, definitely have a conversation.

66:52

Anything less than that should be a chronic GFR.

66:55

You know, somebody who has chronic renal disease

66:57

that you're gonna just scan anyway

66:59

'cause you're not gonna change the

67:01

functionality of their kidneys.

67:03

Um, or you know, if it's brand new GFR low, you know, 30,

67:08

then maybe that's a great time to have a conversation

67:10

with the, with the referral.

67:12

Thank you. Yeah, of course.

67:16

Good evening, sir. Hi.

67:19

Hi. Uh, so let's say like, I don't have, I'm not able

67:23

to get a peripheral line, an anti cubital vein in,

67:26

and I have a central vein.

67:29

Mm-Hmm. What will happen to the protocol?

67:31

Uh, if I have access one lead to a central line?

67:35

Shorter, shorter, shorter.

67:37

Now, if you are doing, uh, uh, IV access

67:41

through the jugular, you know, vena cva, you know,

67:45

and you have for instance, like a, a power line.

67:48

So they, for instance, they are an oncology chemo patient,

67:52

they have then a, a power safe injector.

67:55

You know, something that's gonna be, you know, tri luminal

67:58

in here or dual lumen,

68:00

you know, all those other things there.

68:01

They're typically rated

68:03

and the rating you may have to check,

68:06

but usually they're good for five milliliter per second.

68:10

Um, some of them are six, uh,

68:13

but five is, is really a good one there.

68:16

In terms of what that means from your

68:17

acquisition standpoint.

68:18

You obviously have to begin the acquisition sooner.

68:22

So that bolus technique

68:24

where you're watching the ROI down in the descending

68:27

thoracic aorta, that's gonna kick off much sooner.

68:30

What that means then is your breath hold should not then be

68:34

a breath hold, it should just be tidal volume.

68:37

'cause you will not have enough time to swing

68:40

or sling the, the source to for your temporal resolution.

68:44

And wait the three seconds there.

68:46

So I typically omit verbal instructions to hold breath.

68:49

I typically omit the breathe in,

68:52

breathe out, hold your breath.

68:53

If I have a central line, just

68:55

because it's an, an immediate access into

68:58

essentially, I mean, what is that?

69:00

That's maybe 30 centimeters. 40 centimeters.

69:03

So you gotta get rid of all that, um,

69:04

those automated instructions if that's the kind

69:07

of patient population you're dealing with.

69:10

Thank you. Yeah.

69:11

But like I said, the main thing is make sure

69:13

that whatever you're gonna push the contrast through at

69:16

that rate is rated for that low rate.

69:20

And, uh, five seems to be where most of them are.

69:24

Um, in, in my neck of the world in, in the woods here, six,

69:28

I've seen very few of them that are around six.

69:31

So five should still get you a pretty good exam.

69:34

Okay, thank you. Yeah, of course.

69:37

Hey, Dr. Loren, this is Courtney.

69:38

Um, I received a couple of questions about how

69:42

to locate the cases once, um, the users log into Tara recon.

69:47

Is there a specific, um, location or button in Tara Recon?

69:52

I, I thought that they would just pop up once, uh,

69:55

they logged into their account.

69:57

Yeah, they need to pop up.

69:58

We'll, uh, check with the Tara Recon rep

70:00

to make sure that they're loaded correctly. But yeah,

70:03

I've already reached out to Tara Recon,

70:05

but I thought since we have you here, I would, I would ask,

70:08

but yep, I'm in contact

70:10

with Terry Recon trying to figure this out.

70:12

Yeah. And you guys should see 'em exactly like this

70:15

where it's week ones, then week twos and so forth.

70:18

And, um, your data set is exactly like mine.

70:20

I don't have a cheat sheet data set.

70:21

So I love this course

70:23

'cause I always have to, I keep it real.

70:25

I'm like, oh crap, I missed this,

70:26

or I gotta think about this.

70:28

And, and it's fun because on some of them, not all of 'em,

70:31

but some of 'em, I'm like, dude,

70:33

I totally over called this one.

70:34

Why would I do that? And other times I under called it.

70:37

So that sort of drift, you know,

70:39

inter radiology drift, it's a thing, right?

70:42

And especially when you're dealing with a cad rad system

70:45

where it's percentage zero

70:46

to a hundred percent, it's common.

70:48

So of course we're not gonna be testing you on that.

70:52

It's not like you said, 0% and it's actually 2%. No, no, no.

70:57

It's, if you say 0%

70:58

and actually there's a hundred percent occlusive plaque,

71:01

that's when we'll, we'll go through it.

71:03

But happy hunting and learning here.

71:07

Please send any questions you have to Courtney

71:10

and, and or to us.

71:12

And, uh, I can't wait to see you guys again

71:14

so we can do more, uh, classes together.

71:17

Thanks. Uh, Dr. Yeah. Um, Dr.

71:19

Lorenz looks like we just have one last question from Dr.

71:22

Yeah, I just wanna quickly show you what my problem is.

71:26

I can't see, I don't know if I'm clicking. No.

71:28

Like this is the page I get, so if I take a

71:32

Dr. Sure. Dr.

71:33

Yap, we actually, um,

71:35

we can take this off of the Oh,

71:37

Okay, sure. Yeah.

71:38

The Tara representative will have to assist us.

71:42

Okay, perfect. Thanks. Mm-Hmm.

71:44

We'll get, we'll get you guys on there

71:45

and if not, we have other ways of, of getting it through you

71:49

to via obra

71:51

and we have, so we have a backup to the, to this in case.

71:54

Okay, perfect. Thanks.

71:56

I just don't wanna be the one

71:57

who is not clicking the right button. That's all.

71:59

Thanks. We understand. Hi, Dr. Lawrence.

72:03

Hi. Sorry. I just have a couple of questions.

72:07

Uh, I just wanted to find out if you, uh, sorry,

72:10

I just wanted to ask if you could tell us a bit more about

72:13

photon capturing CT N if it's in mainstream use.

72:17

Uh, I just heard about it, uh,

72:20

just one center that was using it.

72:22

Mm-Hmm. Uh, as to my knowledge,

72:24

but, uh, I wasn't too sure as to what the difference was.

72:27

I, I hear it's a much better, um, acquisition

72:32

mode ra uh, for the cardiac imaging.

72:36

What, gosh darn it.

72:37

Um, I, um, so what it is is, uh,

72:42

I, there was a slide that I showed you

72:44

where the source was sending the radiation down

72:47

and then the detectors were down there.

72:49

Yeah. To define the detector

72:51

or the square, you need the septation in between.

72:55

And the septation is a material

72:56

that is not absorbing of the radiation.

72:59

So it could, the radiation could potentially send,

73:02

go into the, the pixel.

73:05

The problem is, if you wanted to get to the

73:09

spatial resolution that is defined by this artery

73:13

and many other organs, we need to remove the septation

73:17

as the last block of restriction to, um,

73:22

evaluating the, the, the, the material.

73:27

And so the citation is removed

73:30

in what's called a photon counting system, where every,

73:35

uh, peak of radiation from let's say, um,

73:40

uh, four 50, you know, to anything else,

73:44

every peak is counted for by a new material.

73:49

Um, melin molybdenum as it's called, um,

73:52

it's acquired in there.

73:53

So every radiation peak is a picked up.

73:57

There is no noise, which is not counted information

74:01

or counted dose.

74:02

And you are able then to subtract then that if you know

74:06

what it is and where it is.

74:08

So now you have theoretically the highest spatial resolution

74:11

possible because every peak in everything

74:14

there is accounted for.

74:16

Now what you still have is some compton scattering,

74:19

which is a physics component that

74:23

because not all of the, all of the tissue

74:25

of interest is absorbing all of the radiation.

74:28

You know, for instance, the, the fat and the skin

74:30

and all that stuff can absorb it

74:32

and then scatter the electrons in that space there.

74:36

But most of the radiation that's going

74:39

through somebody is not compton scatter image.

74:42

It's that it's not counted for

74:44

or it's below the threshold of the K edge.

74:48

So we are now able then to acquire much more

74:52

beyond just the K edge

74:54

and then subtract that noise out,

74:57

creating then a cleaner image.

74:58

We've been working with this for about since, oh, for me,

75:01

I've been working with it since 2018 at some

75:03

of my centers in the us and it's a very good for, um,

75:09

for coronary, it's very good for interstitial lung disease.

75:12

I'm a cardiovascular radiologist,

75:14

so interstitial lung disease, it's not so good for, um,

75:18

some things that I was really surprised about thoracic, uh,

75:21

or vascular imaging.

75:23

I'm not very happy with it.

75:24

I don't think it does as great as it could do.

75:27

And, but there, those are some technical concerns.

75:30

But essentially what photon counting is,

75:32

it's remove the septation, which is the,

75:34

the was the last threshold in being able

75:36

to get the cleanest image

75:38

and allowing for the counting of the noise.

75:41

Non-competent scatter. That is oftentimes in our image.

75:46

Thank you. Uh, one more question with regards

75:50

to coronary ct.

75:52

Um, how much functional imaging are we

75:55

able to get off the heart?

75:57

Uh, are we able to extract from the volume rather?

76:01

I love this question because this is my thing is like,

76:05

how can I gather more from this system

76:08

if I'm already capturing the system, you know,

76:12

anatomy without using mm-hmm.

76:14

Contracts. So there is correlatives that is the more, um,

76:19

calcium density, um, there is in your si in your tree,

76:24

typically the worse your function is.

76:25

So it's inverse, um, for that thing.

76:28

And it also leads to, on a population basis, um,

76:32

higher increases

76:34

or associations with major adverse cardiac events.

76:36

So that is the higher your CAC score,

76:39

the worse you are probability wise in a population

76:43

setting by race.

76:44

Because we use the MESA criteria that's been studied there,

76:48

but also just density wise, it tends

76:50

to just correlate as well.

76:52

Functionally, same thing that is the, uh,

76:54

metabolic equivalent of work.

76:56

Um, the, the met,

76:58

which is typically used in functioning

77:00

cardiac functioning evaluation.

77:02

So how many mets of work you can do?

77:03

So you and I would probably get up downstairs, we can go

77:06

for a walk, we can do all that stuff without taking a,

77:08

a shortness of breath or dyspnea.

77:10

We've got probably 10 to 14 mets easy, no big deal, right?

77:14

Okay. So that same thing has been correlative.

77:17

That is the more CAC you have, um, coronary artery calcium,

77:21

the worse your mets are.

77:23

So there is an inverse relationship

77:24

to the functionality of that.

77:26

How then can you deploy that in a preventative setting?

77:30

We are still trying to figure out,

77:32

because the calculator based functional assessment

77:36

and then looking at that in terms of then

77:40

what failure is gonna look like

77:41

or even event is gonna look like, that's not accounted for

77:45

yet because of the compensatory mechanism of this body.

77:49

Your body will compensatory, mech, um, you know, mm-hmm.

77:51

Compensate so well that it's not a straight linear,

77:55

it's probably u-shaped

77:56

or it has some other components behind it too.

77:59

Great stuff. I love it

78:00

because then we could combine lung cancer screen, we can do

78:03

that, you know, there's a lot

78:04

of really fun things we could do.

78:05

You know, capture, you know, the heart,

78:07

the coronary arteries, uh,

78:09

and then determine out, like you were saying,

78:11

functional assessments, lot of really great things.

78:14

Opportunistic biomarkers as well have been looked into this.

78:17

So how much, um, sarcopenia, how bone density associated

78:21

with coronary disease, calcium, for instance.

78:24

Um, and plaque for instance, has also been studied.

78:27

Uh, eat, which is the epicardial attenuation of fat, um,

78:32

that has been studied and correlated

78:34

to opportunistic biomarkers, again, sarcopenia

78:37

and bone density and so forth.

78:39

Uh, visceral fat also.

78:40

So we are really getting down into this in terms

78:43

of being able to, from, uh, preventative standpoints,

78:47

look at a lot of different biomarkers

78:49

acquired on a typical ct, um,

78:52

and then be able to make really educated guesses

78:54

on where we're gonna go next.

78:56

So I'm in it from the innovation standpoint.

78:59

I try to fund companies, um,

79:01

and do things, um,

79:02

more than just the interpretation standpoint

79:04

because I want people to get into this.

79:06

I want the, the physicists, I want, the, the,

79:08

the coders I want, you know,

79:10

we can really do some really cool stuff.

79:12

So there's a lot of really good work that it is.

79:14

But, um, in terms of what's out there right now

79:15

and what's guideline based, um,

79:18

coronary artery calcium is associated

79:20

with major adverse cardiac events in a

79:22

linear or uh, fashion.

79:24

And that's about as far as we go.

79:26

But it's not great because

79:28

that does not take into account many other factors

79:31

that have obviously lead to, um, atherosclerotic

79:35

related coronary debt.

79:37

So we'll see.

79:39

Thank you for that. Thank you

79:41

everybody for your questions.

79:43

So we wanna be respectful of everybody's time.

79:45

We're already 22 minutes over.

79:47

So thank you all again for attending.

79:49

If you do have any follow-up questions, feel free

79:52

to forward them to me at cRose@modality.com

79:55

and I will reach out to Dr.

79:58

Loren and Fenni for an answer.

80:00

Um, and just a reminder, this, uh, is being recorded

80:03

and will be made available, um, in 10 business days or less.

80:07

So thank you again Dr.

80:08

Lorenz, for staying on a little, uh,

80:10

while longer to answer questions.

80:12

You guys have a good one. Take care.

80:13

Thank you all. Bye.