0:03

Hello and welcome to Case Crunch Rapid Case

0:05

Review for the core exam hosted by Medality.

0:08

In its rapid-fire format, faculty will show

0:11

key images and you'll respond with the most

0:13

likely diagnosis via the live polling feature.

0:16

After a quick answer explanation, it's onto the

0:19

next case. Recording of all of these live board

0:22

prep videos will be available starting next week.

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Sign up for your free account

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now to have your access secured.

0:29

Today, we're honored to welcome Dr. Elizabeth Hawk

0:32

for a nuclear medicine board prep case review.

0:35

Dr. Hawk is a physician-scientist with dual board

0:37

certification in radiology and nuclear medicine.

0:41

We are thrilled she's here

0:42

today to lead us in this case.

0:43

Questions will be covered at the end of

0:46

time allows, so please remember to use the Q&A

0:48

feature to submit any of your questions.

0:51

And with that, we are ready

0:53

to begin today's board review.

0:54

Dr. Hawk, please take it from here.

0:58

Alright, everyone. I am absolutely thrilled to be

1:01

doing your nuclear medicine case review

1:03

for the ABR core exam this evening.

1:06

Um, just a couple of disclosures.

1:07

Obviously, I'm not gonna be talking about anything

1:09

AI-related this evening, although I'd love to,

1:12

um, perhaps we'll save that for another day.

1:15

So what will we cover today over

1:16

the course of the next hour?

1:19

Nuclear medicine is my favorite

1:21

subspecialty of imaging because it really

1:23

does cover the entire body, head to toe.

1:26

Now, when I normally do a board review case

1:28

style, it's six hours for my UCSD residents.

1:31

Um, and then we can be more comprehensive and, and

1:33

cover sort of all the different things you could see.

1:36

But for tonight, we only have one hour, so it's

1:38

gonna be sort of a rapid-fire, uh, tour through the

1:41

human body, um, with all things nuclear medicine.

1:44

Now, if you're studying for the core exam, uh, I'd be

1:46

remiss if I didn't recommend that you review things

1:48

like radioactivity, radiopharmaceuticals, um, your

1:52

AU and radioisotope safety and hot lab pictures.

1:55

Um, but for tonight, we're not gonna be covering that.

1:57

Uh, what we will do is cover a lot of image

1:59

rich and case-based questions, um, broken

2:03

down, uh, the following four questions on

2:05

PET/CT and then two CNS/MSK and so on.

2:08

Um, I hope you enjoy it and, uh, look forward to

2:11

answering any questions at the end, time permitting.

2:14

So let's start with case one.

2:16

We have a 47-year-old woman

2:18

presenting for breast cancer staging.

2:21

I'll leave a few minutes on this image to

2:23

let you familiarize yourself with

2:25

it, and then we'll move on to the question.

2:30

So, finding annotated by the arrow in this image is

2:36

go ahead and give me your best multiple choice answer.

2:45

We'll give a few moments for everyone

2:47

to, uh, share their thoughts, enter their

2:50

poll, and see how it all turned out.

3:02

See that we've closed and most people said

3:04

metastatic internal mammary lymph node.

3:07

All right, let's, let's break this down a

3:10

little bit and talk about what's going on.

3:14

So in the answer, the answer is

3:15

actually an imaging artifact.

3:17

And this is a really, really important

3:19

thing that I want all of you to recognize.

3:20

Let's go through the case question

3:22

by question panel by panel.

3:23

So the first one is just a MIP showing

3:25

that there is an obvious hypermetabolic

3:27

thing in the region of the mediastinum.

3:30

Uh, now in panel A we have our

3:32

non-contrast-enhanced CT.

3:34

And you can see here that there's a super dense

3:38

thing there where the arrow's pointing to, and

3:40

what that actually is, is that's contrast.

3:42

Entering into the circulatory system, and that looks

3:45

very, very hypermetabolic on the fused image, which is

3:48

panel C. On panel D, we've got our attenuation-corrected

3:52

image, and you can see it still looks very, very bright.

3:55

But panel E, and this is the crux of the question,

3:58

is a non-attenuation-corrected image, meaning

4:01

that it's no longer there, it goes away on the

4:03

non-attenuation-correction image. If you think

4:06

about it, the background of the physics is

4:08

uh, we use attenuation correction or CT images to

4:12

tell the machine and the detectors what the path of

4:16

the signal had to go through to get to the detector.

4:19

So if it sees something super, super

4:20

dense like bone or metal or contrast or

4:23

calcification, it's gonna turn up that signal.

4:27

It thinks that that particle must have had to

4:29

go through something very, very dense to get to

4:31

the detector, and in this case, it's contrast.

4:34

Contrast is very, very dense.

4:35

So it's very important to, to remember that

4:38

this is an attenuation correction artifact,

4:40

that that's not a hypermetabolic lymph node.

4:43

And the crux of the, the question lies on recognizing

4:46

that E is the non-attenuation corrected image.

4:49

All right, let's move on.

4:54

Case two, the cause of this artifact.

4:56

So I'm gonna go ahead and tell you this is an artifact.

4:58

Go ahead, familiarize yourself with these images.

5:07

And let's go on to the question,

5:08

what is the cause of this artifact?

5:20

What do our answers say?

5:22

So some people say photo-multiplier tube.

5:24

Some people say motion.

5:25

Some failure in bed position and

5:27

some have failed CT detector.

5:28

So a little bit of each.

5:29

Um, and those of you that said, uh,

5:32

patient motion are absolutely correct.

5:34

So the most important thing to think about on

5:36

this one is that this artifact presents

5:39

across all the different imaging modalities.

5:42

So it's a PET artifact and it's a CT

5:46

artifact, and it's a fused image artifact.

5:48

Now, if it were a failure in the bed

5:50

position or just one of the individual

5:52

imaging modalities, we'd see it on.

5:54

One but not the other.

5:56

So you'd see it maybe on the PET 'cause the

5:57

PET is taken in bed positions, but not the CT

6:00

because we don't use bed positions for the CT.

6:02

Um, motion is a really common problem that

6:04

we see all the time and usually the most

6:07

problematic area is around the diaphragm.

6:09

'Cause even if the patient's holding still, they're

6:11

still breathing or hopefully they're still breathing.

6:13

Um, and that motion caused by the diaphragm

6:16

going up and down often causes the

6:18

hepatic dome to have a phantom

6:20

or a floating, um, look to it.

6:23

Uh, and it is very, very confusing when we're

6:25

trying to stage tricky things like pulmonary

6:27

nodules at the base of the lungs or, um,

6:29

subtle hepatic lesions in the hepatic dome.

6:31

So really important to recognize that

6:33

this goes across PET and CT images.

6:35

So it's gotta be a problem with the patient, not

6:38

necessarily the equipment on one side or the other.

6:41

All right, moving on.

6:46

Case number three.

6:49

So for this case, I want you to assume that

6:51

this is the same patient imaged four times,

6:53

and I'll show the question on the next slide.

7:00

So here's the question.

7:01

You don't necessarily need the images for the question,

7:04

but I like to have images in my practice questions.

7:17

I know it's a lot of words.

7:18

Sometimes it's hard to work through the words, but

7:21

questions like this will come up over the course of

7:23

the core exam, and it's important to stay sharp and

7:25

resilient and try and wade your way through the words.

7:35

Let's see what people said.

7:36

Great.

7:37

So you guys almost all got this question right?

7:39

The same patient can have highly variable myocardial

7:42

uptake from scan to scan, and, uh, that's super important

7:46

to remember, um, because that, oops, that patient, uh.

7:53

Could present at multiple times, depending on

7:55

diet, depending on many, many different factors.

7:58

Um, the myocardium will look very, very different from

8:00

scan to scan, and it doesn't mean that there's ischemia

8:03

or neoplastic involvement in the heart or pericardium.

8:06

It's just that the heart looks very

8:07

variable across different scans.

8:09

All right, moving on, case number four.

8:13

So this is a 64-year-old male with prostate cancer.

8:20

Let's move on to your question.

8:24

Appearance of the bones is most consistent with,

8:28

and I'll go back to the image if that helps you.

8:41

Let's see what you guys had to say.

8:43

So most people said widespread

8:44

osseous metastatic disease.

8:46

A couple good responses to therapy.

8:48

No one thought it was radiation.

8:49

A couple people thought it was normal.

8:51

So let's see what the answer is.

8:54

The answer is that it's a good response to therapy.

8:57

And let's go back to the image

8:59

to just take a look at why.

9:01

So if you look at this image, the bones look

9:04

diffusely bright, right?

9:06

There are, there's bright bones all over.

9:08

Now, right away you think this could be

9:09

widespread osseous metastatic disease, or you

9:12

think, okay, maybe the patient is receiving

9:15

G-CSF or some kind of marrow stimulation therapy.

9:19

So when I'm kind of stuck in that decision

9:22

point, I always look to the spleen.

9:24

Because if the spleen is also very, very bright

9:26

in a PET CT, um, you know that that marrow system,

9:31

that hematopoietic system is ramped up in responding

9:34

to the therapy, which in this case was G-CSF,

9:37

'cause the patient was very, very neutropenic.

9:39

Now if the bones had been diffusely

9:41

hypermetabolic, but the spleen wasn't, uh,

9:44

then you start thinking of metastatic disease.

9:45

But in this case, there's renal

9:47

excretion, there's bladder excretion.

9:48

This is not a super scan, and the spleen is also bright.

9:51

So then I start thinking along the decision

9:53

making tree of, okay, this is a good response

9:55

to therapy, and the therapy was probably

9:57

G-CSF or some kind of marrow stimulation.

10:00

It's a little bit of a tricky question, but, um,

10:03

important to really think about the whole picture

10:06

and why I'm giving you that picture and what

10:08

organs are bright that necessarily shouldn't be.

10:11

All right, moving on case five 37-year-old male

10:15

history of trauma and we're imaging with TNIC, DTPA

10:22

can almost guarantee you'll see a

10:23

question like this on the core exam.

10:25

It's one of those sort of classic

10:27

do not miss type questions.

10:29

Let's go to the, uh, actual question.

10:43

Let's see what people said.

10:44

Some people say absence of intracranial flow.

10:47

A few people say presence of intracranial

10:49

flow, and some people say, "terant."

10:51

So the reason why I chose to show you this.

10:54

And the reason why I specifically tell you

10:56

that the patient's image with TECHNETIUM 99 D

10:59

TPA A is 'cause you have to understand what

11:01

the radiotracer is and where it's going.

11:04

So some radiotracers will cross the blood-brain barrier

11:07

and go into the brain, and others do not cross the blood

11:11

brain barrier, and they do not go into the brain.

11:14

So this is actually present intracranial flow.

11:16

It's a normal brain scan for brain death,

11:19

and it's important to understand that

11:21

TECHNETIUM 99 DTPA doesn't go into the brain,

11:25

it doesn't cross the blood-brain barrier.

11:26

So what we're looking for here is not

11:29

radiotracer within the brain parenchyma.

11:31

We're looking for present radiotracer within

11:33

all the venous structures of the brain,

11:34

in this case, the sagittal sinus, and the

11:36

coronal sinus and the sigmoid sinuses.

11:39

So it's very, very important to really think

11:41

about which tracer you're using, whether

11:44

or not it crosses the blood-brain barrier.

11:45

And then whether or not it's a normal distribution.

11:47

And in this case, it was a negative brain

11:49

death exam or present intracranial flow.

11:52

Um, and it's a little bit sneaky 'cause

11:55

it does look empty, but it's important

11:56

to understand that radiotracer.

11:59

All right, let's move right along to the next case.

12:01

This is a 68-year-old female

12:02

with a history of memory loss.

12:06

This is the scan.

12:07

Let's move on to the question.

12:11

So the radiotracer used in this examination is, and I,

12:14

I hate these questions of what is this tracer question,

12:17

but try and see if you can put it all together.

12:19

It's a little bit of a cutting edge neuro question.

12:24

I can go back to the image while we're waiting.

12:26

If you want.

12:30

A lot of it tends to look like alphabet soup.

12:41

So most of you got this right?

12:43

That's great.

12:43

This is PET beta-amyloid or an Amyloid scan.

12:46

Uh.

12:48

It's really important to recognize what a normal

12:50

and what an abnormal amyloid scan looks like.

12:52

So this is a scan that we do specifically

12:54

to look for amyloid plaques

12:56

in the setting of Alzheimer's disease.

12:58

And I kind of snuck a second bonus

13:00

question or a bonus teaching case in here.

13:02

Um, I've got a normal example on the right hand

13:05

side and an abnormal example on the left side.

13:08

The radio tracer normally goes to all the white

13:10

matter and produces that beautiful sort of spider-like

13:12

outline of the white matter in a normal distribution.

13:16

If the case is abnormal or positive for amyloid,

13:18

you see these clustered bits of radiotracer

13:21

all over the cortex where it shouldn't be.

13:23

So good job on that case.

13:26

All right, moving right along to case seven.

13:29

We've got a 77-year-old male with a history of prostate cancer.

13:33

Here is the scan.

13:36

I know a lot of you are thinking right away.

13:38

I know this, I know this case.

13:40

I've seen it before.

13:40

Let's see what the question is though.

13:44

So a lot of you probably knew what the case was.

13:46

It's classic, but a lot of board questions

13:49

like to take you to that next level

13:50

and see if you understand the tracer.

14:02

Let's see what people said.

14:04

Chemosorption.

14:05

Near the osteoblast is what most of you said, and

14:09

the answer is chemosorption near the osteoblast.

14:12

So this is your classic MDP bone scan

14:14

and, uh, it's a bonus teaching case.

14:16

I tried to cover as much ground as I could in the hour.

14:18

This is a super scan, so you don't see the

14:21

kidneys or the urinary bladder very much.

14:23

You see a little bit of bladder, but

14:24

this is what we would call diffuse

14:26

widespread osseous metastatic disease.

14:28

And a lot of you would recognize the super

14:30

scan right away, but what I really want

14:31

you to understand is how MDP accumulates.

14:34

Um, and in this case, this radiotracer, um, goes

14:37

on the chemosorptive end of the osteoblastic

14:40

activity, which is why it's really, really great

14:43

at visualizing sclerotic metastatic disease

14:45

and not so much lytic metastatic disease.

14:47

Metastatic.

14:49

Great job.

14:51

All right, next case.

14:51

68-year-old female with a history of breast

14:54

cancer coming in for a staging PET CT.

15:02

Let's go to the question.

15:15

and see what everyone says.

15:16

Great.

15:17

So most of you are saying osteopenia,

15:19

which is the correct answer.

15:23

And what are we looking at?

15:24

What is this?

15:24

This is the classic H or Honda sign.

15:28

Um, I like to think of it as a butterfly, but

15:30

you can think of it as whatever you like, but

15:32

it's classic for sacral insufficiency fractures.

15:35

Um, a lot of these patients are also on different

15:38

therapies that, uh, can lead to osteopenia

15:42

in the bones, um, and then they can develop sacral

15:45

insufficiency or vertebral body insufficiency

15:47

or other insufficiency fractures over time.

15:49

Um, very, very important to recognize that

15:51

this is not usually metastatic disease.

15:54

Uh, now if we were really pressed, could

15:55

there be a metastasis hiding in there?

15:58

Sure, absolutely.

15:59

Um, can a fracture due to trauma also be hypermetabolic?

16:03

Yeah, but it's usually not

16:04

bilateral in a pattern like this.

16:06

Um, and we don't see any signs of osteo erosion

16:09

or, um, sacroiliitis to indicate infection.

16:12

So this is really a, a classic sign.

16:15

The Honda sign or the H that's.

16:16

Related to a sacral insufficiency

16:18

fracture, um, which is osteopenia.

16:21

Okay.

16:22

Case nine 28-year-old presenting for evaluation.

16:28

So I want you to look at this image,

16:29

think about what we might be imaging,

16:34

what we might be using to image.

16:37

And this is the question.

16:50

I've got some six hours, some 13 hours, a

16:54

couple eight days, and a couple 110 minutes.

16:57

Okay, great.

16:59

So the tricky thing about this is some things on

17:03

the core you just need to memorize and I, I hate

17:06

that, but when I was studying for the core, I had.

17:08

Piles and piles of flashcards 'cause some

17:10

things you can't think your way through.

17:12

Now, what makes, uh, this question kind

17:14

of fun or fun for me at least, is that

17:17

you have to take it a step further.

17:18

You can't just recognize the radio tracer.

17:19

You kind of have to recognize which one.

17:21

Right?

17:22

So the answer is eight days because this is I-131.

17:28

Now some of you said 13 hours, uh, because

17:31

you recognized that this was an iodine scan.

17:34

Now you've gotta take it one step further and say, well,

17:36

this is a low dose or a high dose thing, and we can see

17:39

a really, really beautiful star artifact on the neck.

17:42

And that star artifact is created when the

17:45

radiotracer has such a strong energy that it's

17:47

penetrating the collimators, um, and bleeding out,

17:51

you know, beyond where it's supposed to be imaged.

17:53

And that creates that star, um,

17:54

artifact when we're imaging it.

17:55

So we know we're dealing with

17:56

something that's very high dose.

17:58

Something that's very high energy, which means

18:00

this is an I-131 exam, not an I-123 exam.

18:04

And then unfortunately, you just need

18:06

to have your half-lives memorized.

18:07

Um, so that, for those of you that said

18:09

six, that's the Technetium-99m half-life and

18:12

110 minutes, of course, is our workhorse

18:15

in oncologic imaging, F-18 for PET imaging.

18:18

Um, but the important thing to know is that this must

18:20

be a high dose exam and that this is an I-9 exam.

18:23

So eight hours is the right answer.

18:28

Case 10.

18:31

We're staying with our head and

18:33

neck imaging as we tour the body.

18:35

This is the case.

18:36

Let's look at the question.

18:53

All right, so what do we have?

18:54

It looks like a lot of people went for

18:56

a bone pain, vomiting, and depression.

18:58

Some people, uh, voted for B muscle spasm, abnormal

19:02

heart rate, tingly fingers, no votes for C. That's good.

19:05

And uh, just a couple votes for

19:07

sweating, nervousness, and insomnia.

19:10

So, one of the things that I love

19:13

the most about nuclear medicine is.

19:16

We still very much practice patient care and

19:19

the art of, um, medicine with our patients.

19:22

And symptoms matter and a lot of times we get

19:24

consulted to talk about cases and think through

19:27

things, um, and the clinical history and the

19:29

patient symptoms become very, very important.

19:32

Um, now this is a classic parathyroid case.

19:34

We're looking at, uh, parathyroid adenoma.

19:37

And a lot of you probably recognize that when you first

19:39

saw the image, but the question really lies in, well,

19:42

do you know what hyperparathyroidism presents us and.

19:45

Question, uh, answer A has all the sort of

19:48

classic symptoms of hyperparathyroidism.

19:51

B is hypoparathyroidism, uh, C and D,

19:56

uh, deal with hyper- and hypothyroidism.

19:58

So, uh, parathyroid versus thyroid.

20:01

Um, and then it's important to know hyper versus hypo.

20:05

Uh, a lot of these images, and I've annotated them,

20:08

are from a book Metler Essentials of Nuclear Medicine.

20:11

Um, if I had my wish for all of you, it would

20:14

be that you read that book cover to cover.

20:15

It is an excellent book for studying

20:18

for the core for nuclear medicine.

20:19

If you feel like you need a little bit of extra, um,

20:22

material, and all of this is usually covered in there.

20:28

Alright, case 11.

20:30

49-year-old male, history of testicular

20:33

cancer, presenting for staging evaluation,

20:36

and we've got these interesting findings.

20:44

Let's move on to the question.

20:57

What did people say?

20:59

A little bit all over the place.

21:00

So we've got some votes for metastatic

21:02

disease, uh, some for vaccination, some

21:05

for infections, some for foreign body.

21:08

I love this case.

21:09

My UCST residents know that I love showing this case,

21:13

uh, when I do board review because every now and

21:15

then, um, they just like to throw in something fun.

21:18

And this is a fun case.

21:19

I think it's a very interesting case, um,

21:21

and something that's very, very practical.

21:24

I. So what is this?

21:25

This is a foreign body, and this is tattoo ink

21:27

as a foreign body, um, more common than we think

21:30

it is, and more practical than we think it is.

21:32

Um, now if you look back at the case,

21:34

there were bilateral axillary lymph nodes.

21:36

Right now, can you get hypermetabolic, axillary

21:39

lymph nodes in the setting of vaccination?

21:40

Yes, but almost always they're unilateral

21:43

and some, unless someone got.

21:45

Shot in the same arm at the same time that had

21:47

the same kind of reaction to the axillary lymph

21:49

nodes, which would be, um, very serendipitous.

21:52

Um, could it be metastatic disease?

21:54

Sure, it, it could, but those lymph nodes were

21:56

pretty small and it was just in a very symmetric

21:59

and even distribution, which doesn't really,

22:02

um, fit the pattern of metastatic disease.

22:04

And could it be infection?

22:06

Yes.

22:06

But again, so perfectly symmetrical and bilateral,

22:10

um, in small lymph nodes that are not very enlarged.

22:12

Um, you're thinking something else.

22:15

Um, and in this case it's tattoo

22:16

ink, uh, which is a foreign body.

22:18

Um, it's not an infection, it's not an infected

22:20

tattoo, it's just that the ink particles can

22:23

get taken up if they go a little bit deeper.

22:25

Um, and they often get, uh,

22:27

taken up by the lymph system.

22:29

And can, uh, produce an inflammatory response

22:32

or, or hypermetabolic appearance on PET CT.

22:35

So sometimes it's important to think outside the

22:37

box and to really think through different patterns

22:40

of potential disease presentation and to just use

22:43

your general knowledge to sort of help you work

22:45

through why the other answers may not be correct.

22:50

All right.

22:50

Case 12.

22:51

I hate these, but inevitably they'll

22:55

probably show up on the exam.

22:57

So, um, it's a classic one.

23:01

And here's the question for you.

23:14

See what people said.

23:16

Wow, you guys are superstars.

23:18

Everyone said gallium now.

23:21

Don't feel bad if you said indium or sulfur colloid.

23:23

'Cause I almost always get these

23:25

wrong in my own practice questions.

23:27

Um, but this is gallium-67.

23:29

The important thing to think about is that the gallium

23:32

likes to image or, or label the lacrimal glands.

23:35

And you have that kind of classic,

23:36

almost panda face, uh, appearance.

23:40

In this case, it was a positive

23:41

sarcoidosis scan, I believe, from Mettler.

23:43

Um.

23:44

Think about liver and spleen, uh, when you're

23:47

thinking about sulfur colloid or indium-111.

23:50

Indium-111 loves a super, super, super hot spleen.

23:53

Um, go, um, flip through a textbook or some literature

23:57

and just familiarize yourself with the

24:00

look of how these different radio tracers appear.

24:03

Um, gallium is probably one of the most classic

24:05

because of that lacrimal gland appearance.

24:07

Um, so it's kind of the easiest to point out

24:09

out of the, uh, other ones in this group.

24:13

All right.

24:14

Moving along to the cardiac section

24:16

in our whirlwind tour of the body.

24:18

It's a 58-year-old male with a history of chest pain.

24:23

Here are your images.

24:24

We'll give you a minute here to

24:27

familiarize yourself with these.

24:34

There's a lot of different theory about how to

24:36

approach multiple choice, but some people say.

24:40

You should already see the answer or know what

24:42

they're getting at before you see the question.

24:43

And this is the case in this one.

24:45

Um, but here's the question nevertheless.

24:58

So most of you are saying

24:59

reversible anterior wall ischemia.

25:02

Um, a couple saying irreversible.

25:04

Irreversible scar.

25:06

Um, let's, let's walk ourselves through this answer.

25:11

So this is a reversible anterior wall ischemia.

25:15

Um, if we go back really quick just to the annotation,

25:17

you're gonna see lots of annotations when you take an

25:19

exam and everyone's kind of nervous and they're like, oh

25:21

my gosh, I don't know what all these letters stand for.

25:24

But just take a step back and think logically something

25:27

ends in an "s," it's probably gonna be your stress.

25:29

If something ends in an "R," it's

25:31

probably going to be your rest.

25:32

And if you can't figure out the rest of it, that's okay.

25:35

Um, but just try to think logically.

25:36

through different annotations 'cause.

25:38

Different weird annotations can show up.

25:40

Um, oftentimes there's what I call an

25:43

iatrogenic arrow or an arrow sign where

25:45

they like to point out what's going on.

25:47

And this is the case in this question.

25:50

Um, and just in case you're not used to looking

25:52

at these different, um, SPECT images, often they

25:55

provide this bullseye diagram that kind of shows

25:57

you a different perspective on what's going on.

26:00

And in this case, it's very

26:01

clearly labeled stress and rest.

26:03

So what you have is an area of photo or a defect.

26:07

In the stress imaging that then normalizes

26:10

on rest imaging, and that's a classic

26:12

pattern for something that's reversible.

26:14

So it's only present on stress, not present on rest.

26:18

Um, there's a lot of different

26:19

diagrams that you can look up.

26:21

Again, this one's from Mettler.

26:23

And you can memorize them for the parts of the

26:26

wall because it's very, very important to know

26:28

your coronary artery anatomy and your wall anatomy.

26:31

So understanding which part is anterior,

26:34

inferior, septal, and lateral is gonna

26:36

be key to getting questions like this.

26:38

Correct.

26:39

So spend some time with the bullseye diagram.

26:41

Um, just familiarize yourself

26:43

with the anatomy and the terms.

26:45

Um, and then just.

26:48

Kind of take a breath when you see annotations

26:50

or presentations that you don't know and

26:52

allow your logical brain to work through them.

26:54

I know it's easier said than done under

26:56

a stressful situation, but usually

26:57

you can work through what's going on.

26:59

So in this case, this is

27:00

reversible anterior wall ischemia.

27:04

All right, moving on

27:07

Case 1480: 2-year-old woman presenting

27:09

for cardiac clearance evaluation.

27:12

A lot of these cases are for pre-op clearance,

27:15

so I'll give you a few minutes with this image.

27:18

Familiarize yourself with it.

27:27

And let's go to the question

27:40

and let's see what people say, a

27:42

little bit all over the board.

27:43

Some people say acute ischemia.

27:45

Some people say hibernating myocardium.

27:47

Some people say an aneurysm.

27:48

Some people say hypertrophic cardiomyopathy.

27:52

Maybe this isn't the best question in the

27:54

world because there are a lot of sort of

27:56

potential, um, answers or potential things

27:59

that could be going on at the same time.

28:01

But in this case, this is a

28:02

super classic sort of anterior

28:06

image of a left ventricular apical aneurysm.

28:09

Now remember when we say aneurysm, it

28:10

doesn't necessarily mean it's an aortic

28:12

aneurysm or a, a different vessel.

28:15

It could be an apical aneurysm.

28:17

Um, and in this case it's not, uh, acute, uh, ischemia,

28:20

because it's not, doesn't change on rest and stress.

28:24

Um, we can't really tell if it's hypo-, hibernating,

28:26

myocardium or not because we don't have the viability

28:28

images to be able to see if that's the case.

28:32

Um.

28:32

Could this person have hypertrophic cardiomyopathy,

28:35

underlying, maybe, but usually you see sort

28:37

of a diffusely enlarged ventricle without

28:40

this giant aneurysmal defect at the apex.

28:43

So it's probably not what we're

28:44

trying to get at for this case.

28:46

In this case, this is the really classic left

28:48

ventricular apical aneurysm, and it'd be really

28:50

important to, to recognize this and let them know

28:52

about this prior to, uh, cardiac clinics for surgery.

28:56

All right, case 15.

29:01

On to, uh, pulmonary.

29:08

So again, look at these images.

29:11

Uh, you can probably already tell what type of question

29:14

is gonna be written with these types of findings.

29:17

So think in your head, what would she

29:19

ask if she was writing a question?

29:21

And

29:24

here's our question.

29:36

Let's see what everyone says.

29:39

So a lot of people are saying large pulmonary embolism.

29:42

Some people are saying congenital defect.

29:44

Some people are saying neoplasm, and

29:46

some people are saying infection.

29:48

Nope, no one's saying infection.

29:49

That's great.

29:50

All right, so what are we dealing with in this case?

29:53

Let's talk about it.

29:54

So the answer is actually neoplasm.

29:56

This is a case of lung cancer and a lot of

30:00

you're gonna say right away, whoa, wait a minute.

30:02

Why isn't this a large pulmonary

30:03

embolism and a very, very large pulmonary

30:06

embolism that takes out the entire lung?

30:08

Yes, that could happen.

30:09

That could create that massive perfusion defect.

30:12

But the reason why this case is put

30:14

together in this manner is because we're

30:16

looking at a large mass on the chest x-ray.

30:20

A mass that's big enough that we can actually

30:22

just see it on the single view radiograph.

30:25

Um, if it were a very, very large pulmonary

30:27

embolism, we wouldn't necessarily see a mass there.

30:31

Um, but in this case, there's a large

30:33

mass in this region, which, um, ultimately

30:36

constricts the left pulmonary artery and

30:38

results in absence of flow to the left.

30:41

He has, and just to walk through it completely.

30:44

Our ventilation images are, are normal.

30:46

That's pretty uniform ventilation.

30:48

Depending on the position of the patient,

30:50

sometimes there'll be a little bit of

30:51

decreased ventilation at the apices, but that's

30:54

sort of to be expected with the technique.

30:56

Perfusion image shows complete absence

30:58

of perfusion to the left hemithorax, and

31:01

then we move down to our radiograph.

31:02

Remember, in order for a VQ scan to be, um,

31:06

technically sensitive and specific enough

31:09

to be used, we need a chest radiograph,

31:11

uh, in close proximity to the VQ scan.

31:15

In this case, you really need to scrutinize that

31:16

radiograph, and you can see that very, very large

31:18

mass, which pushes us toward the most likely answer of

31:22

being a neoplasm rather than a large pulmonary embolism.

31:27

All right.

31:28

I know that's a little bit tricky, but I just

31:30

want you guys to not jump at the very, very

31:32

obvious nuclear medicine finding, but to use

31:35

all of the information that's given to you,

31:37

and in this case, the chest radiograph is key.

31:43

Here is another bit of an Ant Mini.

31:50

We'll spend a few moments on this image just

31:53

so you guys can get your lay of the land,

32:00

and let's go to.

32:13

Let's see what you guys thought.

32:14

We're a little bit all over the place.

32:16

Uh, a little bit of votes for everything.

32:18

Um, this one's a hard one.

32:19

It's a hard one to tease apart

32:21

piece by piece.

32:21

Piece by piece.

32:23

Um, some people may think, uh,

32:25

free protect something like that.

32:28

Um, some people may think, well, there's a

32:30

right to left shunt, but we're not really

32:31

seeing the brain or, or other things like that.

32:33

Um, what this is, is this underlying

32:36

pathology, and it is, um, hepatic steatosis.

32:39

So this is a classic, uh, ventilation image for a

32:42

pulmonary exam, and it was done with Xenon-133.

32:45

And with Xenon-133, it's a well-known fact

32:48

that it actually will accumulate in the

32:50

liver, in the setting of hepatic steatosis.

32:53

It's kind of one of those T-minis that you

32:54

just need to see, know, learn, understand.

32:58

Um, this is because xenon is soluble in fat.

33:01

Uh, so we see it in hepatic steatosis.

33:05

Uh, if you wanna read more about this or see

33:07

this case in particular, it's in Mettler as well.

33:09

Um, it's one of those ones that I kind of just had

33:11

to learn when I was studying for boards as well.

33:14

But a really good aunt, many for all of you guys to see.

33:19

All right, here's another one we're moving on to

33:22

GI. Uh, for me, there's a lot I could have shown

33:26

you in GI. Uh, there's all sorts of things from

33:29

acute GI bleeds to tagged white blood cell scans

33:32

to Meckel's diverticulum, to all sorts of things.

33:35

But I only had two cases and when I was studying for

33:38

boards, what I struggled with the most was liver.

33:41

I know about you, but I thought

33:42

the liver lesions were super hard.

33:44

So we're gonna do a couple liver questions.

33:46

This is a 37-year-old woman who had a liver lesion

33:50

and they're trying to figure out what it is, so go

33:52

ahead and familiarize yourself with the images.

33:59

Let's see what kind of question we're gonna ask.

34:12

See what you all said.

34:14

We've got a few votes for everything.

34:16

Most of you are calling this a hemangioma.

34:19

Um, let's see what we have.

34:23

So this is indeed a hepatic hemangioma.

34:25

Good job.

34:26

So what we have first are, uh,

34:29

the technetium-99 sulfur colloid scan.

34:31

Um, and we've got a cold defect where that lesion is.

34:34

So it doesn't take up sulfur colloid, or it

34:36

takes up less than the surrounding hepatic tissue.

34:39

Um, then you've got your, um, tagged red blood

34:41

cell scan, and you know that that's a red blood

34:43

cell scan in panel B in the bottom panel.

34:46

'Cause you can see all the vessels

34:47

and the heart is lighting up.

34:49

Um, it looks like an angiogram

34:51

or a very unclear angiogram.

34:53

Um, so you know that that's

34:54

a tagged red blood cell scan.

34:55

So that lesion is just lighting up

34:57

on that tagged red blood cell scan.

34:59

Um, and then we've got our SPECT-CT.

35:02

So we've got a CT to go with that red blood cell

35:04

scan, and we've overlaid them on a fused image to

35:07

show that that intense radiotracer localization in

35:10

the red blood cell scan localizes to that liver.

35:14

So you've got something that's cold on

35:15

your sulfur colloid scan and then hot

35:18

on your tagged red blood cell scan.

35:20

Um, and that's really classic for a hemangioma.

35:23

It's a great way to sort of work up that lesion.

35:25

Um, before MRI was widely popular.

35:28

Nuclear medicine will really, the experts in this and

35:30

uh, a lot of these questions tend to still show up.

35:35

Show.

35:35

All right, let's do one more liver question.

35:37

This is a 37-year-old woman with a liver lesion.

35:40

Let's see what you guys say.

35:47

Here's our question.

35:58

Let's see what you guys thought.

35:59

A few.

36:00

Hepatocellular carcinomas.

36:02

One vote for mets, uh, a bunch of FNH.

36:05

Great.

36:06

And no one voted for angioma.

36:07

Of course, I wouldn't show you two.

36:08

Angios in a row.

36:09

That would be a little bit cruel.

36:11

So the answer is FNH.

36:14

So first we've got our just standard

36:15

contrast-enhanced CT of the liver.

36:18

Um, we gave you a little bit of a

36:19

hint because this is a young woman.

36:22

Uh, if I really wanted to give you an extra

36:23

hint, I would've said on oral contraceptives.

36:26

Um, and this is a well-defined focal low-density lesion.

36:31

Sort of classic rounded appearance.

36:33

And then we have a liver spleen scan, right?

36:35

Your sulfur colloid scan.

36:37

Um, and that scan shows, uh, similar distribution, uh,

36:43

in the region of the, in the region of the liver.

36:46

So there's normal, we really don't see

36:48

any uptake in the sulfur colloid scan.

36:50

So it's a discrepancy or a mismatch.

36:53

Um, and it's really, really classic

36:54

for FNH or focal nodular hyperplasia.

36:57

Is a prime consideration.

36:58

It's, um, really, really important that you

37:00

don't send this, um, young woman down the path of

37:04

hepatocellular carcinoma or metastatic disease.

37:08

Um, this is just a classic FNH type case.

37:14

All right, let's move on to renal.

37:19

Renal transplant tends to be a little extra

37:21

tricky, uh, beyond just the renal case.

37:24

So since we only have two, I thought

37:25

I'd give you a transplant case.

37:27

You can go ahead and familiarize

37:28

yourself with these images

37:36

and let's look at the question.

37:47

So most of you are saying ATM or acute

37:50

tubular necrosis, which is great.

37:52

These questions can be a little tricky.

37:55

Um, and sometimes just the fact that

37:57

it's a renal transplant scares us a

37:59

little bit 'cause it's unfamiliar.

38:01

And although many of you have seen

38:02

probably a lot of renal cases only, um.

38:05

Handful of transplant cases

38:07

come across us in our training.

38:09

Um, but this is really, really classic,

38:10

uh, ATN or acute tubular necrosis.

38:13

So we've got our anterior perfusion images,

38:15

that's a right pelvic transplant kidney

38:18

or right iliac fossa transplant kidney.

38:21

And we've got normal perfusion.

38:23

Initially, we've got our 1, 2, 3, 4 second flows.

38:26

Um.

38:27

Then our renogram show sort of this

38:29

increasing sort of growing parenchymal

38:32

activity over the next, um, up to 45 minutes.

38:35

We've imaged this patient.

38:37

And so the radiotracer is just kind of sitting

38:39

in the renal cortex and just staying there.

38:42

Um, and that's really, really classic for acute

38:45

tubular necrosis, which is a very important diagnosis

38:48

to recognize in the setting of transplant medicine.

38:52

Um, a leak, usually you would've seen progressive

38:54

pooling, uh, in the pelvis from, uh, urine

38:58

that's leaked out of the renal collecting system.

39:00

It's a very common complication in renal transplant.

39:03

Or sometimes you'll see leaks in post

39:05

cholecystectomy cases for bile leaks.

39:07

Um, this isn't a normal exam 'cause you

39:09

shouldn't have that persistent sort of

39:10

perfusion that's just growing over time.

39:13

Um, and it's not chronic rejection.

39:16

It's acute tubular necrosis in this case.

39:21

One more renal case for us.

39:24

Evaluate worsening renal function,

39:27

really common clinical history.

39:31

There's a lot going on in the slide, so

39:33

I'll stay some extra minutes to let you

39:36

really process everything that's going on.

39:43

I feel questions like this, especially toward

39:45

the middle or the end of the exam, are really

39:47

taxing when our brains are already a little

39:49

fried from being stressed out for so long.

39:52

And although they may be patterns and curves that

39:54

you're used to seeing, it's really important to

39:56

read all of the words that are labeled so that

39:59

you know exactly what it is you're dealing with.

40:01

'Cause this is a little bit out of the ordinary.

40:08

Let's move on to the question.

40:19

All right.

40:19

We've got a few votes for mechanical

40:21

obstruction, some for arterial stenosis.

40:23

No one fell for the venous stenosis strap

40:26

and one vote for pilo, and the answer is.

40:31

Arterial stenosis.

40:32

So, uh, a lot of times when you see these renal

40:34

exams, it's gonna be pre and post Lasix, right?

40:37

Uh, Lasix is the classic drug that kind of stimulates

40:40

the kidneys to give up the urine and push it through,

40:43

uh, the outlet, uh, and into the urinary bladder.

40:47

This is not a Lasix evaluation.

40:49

This is a captopril evaluation.

40:51

And captopril is the agent that we use

40:53

to evaluate for renal artery stenosis.

40:57

So these are classic mag three grams.

41:00

Um, pre captopril, uh, they're

41:03

slightly asymmetric activity, right?

41:05

If you look at those two curves

41:06

that are still up, the, uh,

41:08

right.

41:08

Kidney is struggling a little

41:10

bit more than the left kidney.

41:11

Um, but post-captopril, you get sort

41:14

of an exaggeration of what's going on.

41:16

Um, and then you get that marked abnormal retention

41:19

of radiotracer, um, activity in the right kidney.

41:23

It just kind of continues to retain radiotracer

41:26

and doesn't, doesn't let it go, and doesn't,

41:28

um, excrete it into the collecting system.

41:31

So this is a really, really classic case of, um.

41:36

Of, uh, renal artery stenosis.

41:38

And it's important to recognize even though those

41:39

slides are very, very busy, that you're dealing

41:41

with a captopril exam and not a Lasix exam.

41:46

All right, so we're gonna start wrapping up, um, and

41:49

I'll give you a few words of wisdom and how I would

41:53

love all of you to approach studying nuclear medicine.

41:56

Um, for the core.

41:58

Um, nuclear medicine, a lot of

41:59

people joke, it's unclear medicine.

42:02

You'll see lots of cases in the middle

42:04

of the test that look a little confusing

42:06

or just look like giant ink blobs.

42:09

Um, some people just say it looks

42:10

unclear because it's all fuzzy.

42:12

And, and that's true to some extent.

42:15

But what I love about nuclear medicine is it's

42:17

really just about common sense about thinking

42:19

through physiology and um, understanding how the

42:23

radiotracers interact with the human body and then

42:25

seeing what doesn't fit or what doesn't make sense.

42:28

And usually, you can work your way

42:29

through the questions that way.

42:30

Um, try to eliminate your obviously wrong distractors,

42:34

and then walk through the potential right answers, just

42:36

with your knowledge of the human body and physiology.

42:39

Uh, unfortunately, there are a few things that you

42:41

do have to memorize, and those are half-lives, um,

42:45

energies of radio tracers, and then a lot of the

42:48

stuff that we didn't cover today that has to do with

42:50

the regulatory requirements and the dose limits to

42:53

different parts of the body and things like that.

42:56

Um, I will say I've looked at a lot of different

42:59

board review, um, presentations over the months and

43:04

years over my training and my attending-hood, and

43:07

almost everyone builds their board reviews off of

43:09

MET One, which is the Essentials of Nuclear Medicine.

43:12

It's a great book.

43:13

It's, uh, fairly easy to read and all the

43:16

cases are ant-minis or classics that are

43:18

likely to show up in a testing scenario.

43:20

So, uh, I don't have any stake in the book.

43:22

Obviously, it's a conflict-free recommendation, but,

43:26

um, if you're looking for one fantastic source, uh,

43:29

Metler is supported as the go-to for nuclear medicine.

43:33

Um, so with that, good luck.

43:35

I will, uh, be happy to open it

43:36

up to questions, comments, uh.

43:40

Questions on other exam resources, whatever

43:42

you like, uh, open it up to the group.

43:47

Dr. Hawk, thank you so much

43:48

for that amazing case review.

43:50

That was awesome.

43:51

And, um, yeah, we will open up the floor for

43:54

any questions, so if you have questions, go

43:56

ahead and put them in that Q and A feature.

43:59

Dr. Hawk, I'm not sure if you're able to open it up on

44:01

your end to see we've got a question in there already.

44:04

I, yes, you can move it around so I can see it.

44:09

I see for case 19, how would chronic rejection appear?

44:14

Um, it depends on what, what, what we're looking at.

44:16

If it's really chronic, the

44:17

kidney just wouldn't be working.

44:18

Um, so the, the most classic chronic

44:20

cases, the kidney wouldn't be functioning.

44:22

There wouldn't be any uptake of radiotracer.

44:24

There wouldn't be any excretion of radiotracer.

44:27

Um, they could show you any spectrum of

44:30

acute to chronic.

44:31

But my guess is if they're showing you something

44:33

where it's cloudy and staying in the renal

44:35

cortex, it's gonna be a TN chronic rejection.

44:38

Is the kidney's just not working?

44:40

Um, like if we went back to that case and we

44:42

imaged up in the upper abdomen with the patient's

44:44

native kidneys that were no longer working, you

44:46

would just see no radiotracer there at all.

44:49

I hope that helps.

44:53

Any other questions from the group?

44:54

You guys are quiet.

44:57

Sometimes it takes a second, so we'll, we'll hold for

45:00

a couple, couple moments to see if any come flying in.

45:05

And also, I, I hope all of you, uh, follow Modality

45:08

online across their different social media outlets.

45:11

They've tagged me as well in this post.

45:13

If you wanna reach out and ask me additional

45:16

questions or connect in that space, I'm always happy.

45:19

To mentor students, encourage

45:20

students, and connect with students.

45:22

Boards are a super difficult and stressful time,

45:26

uh, and I know you guys all have a lot on your plate

45:29

and are trying to juggle a lot of things, uh, which

45:31

is why I'm really, really excited to partner with

45:34

Modality to sponsor some memberships to Modality.

45:37

So, um, please check out that info and, uh, hopefully

45:41

one of you that join me tonight will win a sponsored

45:44

membership to Modality that would make me really happy.

45:51

So nice of you, Dr. Hawk.

45:52

Really appreciate you paying it forward like that.

45:54

That's, that's awesome.

45:57

Let's see.

45:57

Do we have another question?

46:00

I will type an answer to that question.

46:02

All right.

46:03

Um, we can go ahead and wrap up if

46:05

anybody has any other questions.

46:07

Like Dr. Hawk said, uh, you can follow Medality

46:09

online and find her contact information there.

46:13

Thank you so much again, Dr. Hawk,

46:14

for this amazing case review.

46:16

It was awesome, and I hope everyone else enjoyed it.

46:19

And thank you so much for participating to our audience.

46:22

Thanks everyone.

46:24

Good luck.

46:26

Be sure to join us next Monday,

46:28

March 18th with Dr. Navid Raji.

46:30

Well, he will do a rapid review of MS & MSK cases.

46:34

You can register for it at the link

46:35

provided in the chat and follow us on social

46:37

media for updates on future case reviews.

46:40

Thanks again for learning with

46:41

us and we will see you soon.