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Hello and welcome to Noon Conference, hosted by Modality

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Noon Conference connects the global radiology community

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through free live educational webinars that are accessible

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for all and is an opportunity

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to learn alongside top radiologists from around the world.

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Today we are honored to welcome Dr.

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Ronney Keff for a lecture entitled evaluation

0:21

of HCC Treatment Response.

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Dr. Campbell lab completed his radiology residency at the

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University of Chicago

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and abdominal imaging subspecialty training at

0:31

MD Anderson Cancer Center.

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He's on the abdominal imaging staff at the University

0:36

of California Irvine.

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And his academic interest include the imaging of HCC

0:40

and inflammatory bowel disease.

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As a heads up, there will be polling questions throughout

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today's lecture, and please join him in a q

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and a session where he will address questions you

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may have on today's topic.

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After the lecture ends, please remember to use that q

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and a feature to submit your questions so we can get to

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as many as we can before our time is up.

1:00

With that, we're ready to begin today's lecture.

1:02

Dr. Campbell laugh, please take it from here.

1:05

So I'm gonna talk today about the evaluation

1:08

of HCC treatment response.

1:10

Thank you so much for that introduction.

1:13

Um, so it's a bit of a confusing topic.

1:15

Um, and so there are a couple things I'd like to address

1:19

to help maybe clear up, uh, the confusion around, um,

1:23

evaluation of HCC treatment response.

1:25

Um, so by the end of this talk, uh, I'd like you to be able

1:29

to apply the 2024 RADS treatment, uh,

1:33

response algorithm in patients with HCC treated

1:36

with local regional therapy,

1:37

and then understand the most important changes in the new

1:40

treatment response algorithm.

1:43

Uh, particularly understanding why the new algorithm

1:45

contains, uh, uh, separate decision trees for radiation

1:49

and non radiation based therapy.

1:51

So if you don't know about my institution,

1:53

this is University of California Irvine.

1:55

It's the only academic, um, university affiliated, um,

1:59

hospital in Orange County, California.

2:01

Uh, this is our main hospital located in the city of Orange.

2:05

It's a 450 bed plus, uh, hospital.

2:08

And, uh, opening early next year is our new hospital.

2:11

This is gonna be about 30 minutes south, uh,

2:13

of the main hospital in the city of Irvine.

2:16

Uh, and this is expected to open in, um, early 2026.

2:20

So at our institution, we do a lot of local regional therapy

2:23

for HCC.

2:24

Uh, the last year I checked, um, we did, um,

2:28

about 12 ablations, 36 embolizations,

2:31

and, uh, almost 60, uh, y 90 radio embolizations, uh,

2:35

in patients with, uh, suspected or with with HCC.

2:43

So, uh, let's talk a bit about local regional therapy.

2:45

So what, what is the purpose of local regional therapy?

2:48

Well, uh, four big categories.

2:51

One is to downstage

2:52

or debulk tumor in patients, uh, who are, uh,

2:55

transplant candidates, um, achieve local tumor control, uh,

2:59

in patients who, um, uh, are undergoing transplant

3:03

to reduce the risk of recurrence

3:05

and to reduce the rate of tumor progression

3:07

or prolonged survival in patients

3:09

who are not surgical candidates.

3:11

And local regional therapy comes in two main flavors, right?

3:13

Non radiation therapy

3:15

and radiation based, uh, local regional therapy.

3:19

So the non radiation based therapies can be further

3:21

subdivided into arterial based therapies

3:24

and percutaneous therapies.

3:27

So in arterial based therapies, you're basically, um,

3:30

introducing some sort of embolic agent via into the HCC

3:34

arterial blood supply, either chemotherapy coated or bland.

3:38

Uh, and the goal is to eliminate arterial inflow

3:40

to the tumor and cause cell death.

3:43

The other type of non radiation based therapy is

3:45

percutaneous, um, therapy radiation, uh,

3:48

radiofrequency ablation or microwave ablation.

3:52

Um, in these therapies, um,

3:54

an electrode is gonna create high temperatures using

3:57

different types of energy, uh,

3:59

creating coa coagulation necrosis of the tumor.

4:02

There's also cryoablation,

4:03

which uses a cold energy source to cause cell death.

4:07

So here's an example, right?

4:08

Here's a patient with Hepatitis B

4:10

and HHCC who is treated with microwave ablation,

4:13

and this is the post-treatment scan.

4:15

So on your left is the pre contrast, uh, image,

4:18

and you can see there's, um,

4:19

there's a lesion here in the anterior right hepatic lobe

4:21

with some intrinsic T one hyperintensity probably

4:24

representing blood products, coagulation necrosis.

4:27

You can see on the arterial phase

4:28

and the venous phase images, there's no, uh,

4:31

arterial phase, hyper enhancement.

4:32

So this is an expected, uh, good result from successful, uh,

4:36

microwave ablation.

4:39

So radiation based local regional therapy.

4:42

Um, two main types.

4:44

Um, the type

4:45

that interventional radiologists use most often is

4:47

transarterial radio embolization.

4:50

Uh, we're injecting Y 90 microspheres into the hepatic

4:53

arteries to give a target irradiation uh, dose

4:56

and a small micro embolic effect.

4:58

Uh, this is important. The therapeutic effect of, uh,

5:01

tear is mostly due to the radiation

5:04

and much less so due to the embolic effect.

5:07

The second type is SBRT stereotactic body radiation therapy.

5:11

Here we use beams from

5:12

outside the patient focused on the area of interest

5:15

to deliver higher doses of radiation to the tumor

5:18

and spare the surrounding parenchyma hopefully.

5:22

Um, so

5:23

after therapy follow-up, uh, imaging is

5:27

decided mostly based on the discretion

5:29

of the treating physician, either interventional radiologist

5:32

or the, uh, radiation oncologist At our institution,

5:36

we use multi-phase CT or MRI, um, usually four to six weeks

5:40

after taste, six to eight weeks after tear

5:42

and more, more, more

5:44

or less every, uh, three to six months thereafter.

5:48

Um, so I forgot

5:50

to mention I do have some audience response questions in

5:52

this, uh, in this talk.

5:53

So I wanted to start with the first question,

5:56

and that is, at your institution, what modality do you use

5:59

to evaluate HCC, um, um, after local regional therapy?

6:04

Is it only cd, ct?

6:06

Uh, only MRI mostly CT or mostly MRI.

6:09

And I'll give you a few seconds to answer that.

6:16

Alright, great. So it looks like, um, a, uh,

6:21

a good percent of you, uh, percentage of you,

6:23

51% use mostly MRI, um, followed by mostly CT

6:28

and the minority use, uh, exclusively CT or MRI.

6:31

Okay, very good. Moving onward.

6:34

Okay, so I'm gonna talk about rads.

6:37

Um, the rads, um, algorithm, as you know, uh, probably was,

6:42

uh, trademarked by the A CR in 2011.

6:45

Um, it's a method of standardizing, um,

6:49

and introducing a, a standardized nomenclature, um,

6:52

for findings in patients at risk for, um, HCC.

6:57

Uh, and it helps us communicate

6:59

with our referring physicians.

7:00

It helps, um, standardize categories

7:03

and then it, it helps facilitate research.

7:05

Um, in 2000, in the 2017 version of IRADs, um,

7:10

the algorithm Inc included a treatment response algorithm,

7:14

uh, which offered guidance, uh, on how to evaluate, um,

7:18

patients who had been treated with local regional therapy

7:21

to determine whether the therapy was successful.

7:24

So in 2024, the treatment response algorithm was revised

7:29

and the main change was

7:30

that there's now a different treatment, um, decision pathway

7:34

or a different algorithm for non radiation

7:36

and radiation based therapy.

7:39

So why is that? Um, the reason the authors

7:42

of the algorithm had to make that change was

7:44

because radiation based therapies create a very different

7:46

post-treatment appearance

7:47

of HCC than non radiation based therapies.

7:51

Uh, namely the, uh, response of tumor to radiation is slow

7:55

and prolonged as you have inflammation, DNA damage,

7:59

which can act over a long period of time.

8:01

So, as I said earlier, Y 90 radio embolization,

8:05

the effects depend more on the radiation effect,

8:07

much less on the embolic effect.

8:09

So at the cellular and the radiographic level, the evolution

8:12

of changes after radiation are very slow.

8:16

So for US radiologists, what that means is

8:19

that persistent tumoral arterial phase hyper enhancement can

8:23

persist for six months, 12 months, or even longer

8:25

after radiation based therapy.

8:28

Basically, you have sleepy cancer cells undergoing radiation

8:31

related changes, um,

8:33

and, uh, the effects on tumor size may also be slow.

8:37

Meanwhile, to the surrounding liver,

8:39

you have these microvascular changes.

8:41

You have these geographic peritumoral

8:43

enhancement edema and hemorrhage.

8:45

Um, and sometimes and often you develop fibrosis

8:48

with delayed enhancement, capsular retraction

8:50

and intrahepatic bili dilatation, which we'll see coming up.

8:55

So with this new treatment response algorithm

8:57

after radiation, really the emphasis is more on the changes

9:01

over time rather than the appearance at any

9:03

one given time point.

9:05

Um, so like I said, mass like enhancement can persist

9:09

after successful therapy, but new

9:11

or increasing mass like enhancement is suspicious,

9:14

particularly if it occurs

9:15

after a long period of stability, uh,

9:18

and new diffusion restriction

9:20

and T two hyperintensity can be helpful in

9:22

cases that are equivocal.

9:25

Okay, so let's go to the algorithm.

9:27

I'm gonna start with non radiation therapy,

9:29

the non radiation therapy algorithm,

9:31

'cause that's probably the most familiar.

9:34

Um, so step one, you have these four categories, right?

9:37

LRTR, non evaluable, um, non LRTR, non-viable,

9:42

LRTR, equivocal and LRTR viable.

9:45

So what you're assessing

9:46

for when you do your initial assessment of the imaging,

9:49

look, you're looking for mass like enhancement.

9:52

So no mass, like enhancement means LRTR, non-viable

9:56

uncertain mass, like enhancement is LRTR, equivocal

10:00

and mass like enhancement is LRTR viable.

10:03

This is after non radiation therapy.

10:06

So what is mass like enhancement?

10:08

So it's an enhancing area, any degree, any phase

10:11

that occupies space.

10:13

So nodular enhancement, irregular peripheral enhancement,

10:16

or a thick rim of enhancement all count

10:18

as mass like enhancement.

10:20

So here's an example. Here's a patient who was treated

10:22

with microwave ablation.

10:24

Um, this is three months after microwave ablation.

10:27

Uh, here's the T one pre contrast imaging.

10:30

Uh, on your right is the arterial phase imaging.

10:33

Uh, so you can see that there's nodular arterial phase,

10:36

hyper enhancement around the treated area.

10:38

This is considered mass like enhancement.

10:40

So this is LRTR viable disease.

10:44

So we've seen mass like enhancement,

10:46

what's not mass like enhancement.

10:48

So complete lesion disappearance, no enhancement

10:52

of the lesion, a smooth rim of enhancement around the lesion

10:56

or surrounding parenchymal perfusion changes.

10:59

None of these count as mass like enhancement,

11:01

but these are all findings that you may see after treatment,

11:04

and these do not necessarily represent viable disease.

11:08

Uh, here's an example of HCC status post, uh, taste,

11:12

and you can see the treated area here in the

11:15

right hepatic lobe.

11:16

And then on the post contrast image, you can see sort

11:19

of this geographic wedge-shaped enhancement in the

11:21

parenchyma, uh, around the lesion.

11:24

This is not considered mass like enhancement.

11:26

So this is LRTR non-viable. Uh, here's another example.

11:30

HCC, uh, status post microwave ablation.

11:33

On your left is the pre contrast image.

11:36

You can see that there's a treated area here

11:37

in segment eight of the liver.

11:39

Uh, it has some intrinsic T one hyperintensity.

11:42

Um, but on the post contrast image,

11:45

you don't see any nodular enhancement.

11:47

You see a thin rim of per lesional enhancement.

11:50

Again, this is not mass like enhancement,

11:52

this does not indicate viable disease.

11:54

This is LRTR non-viable.

11:58

Okay, so once you've, um, looked for mass like enhancement,

12:02

step two in the non radiation algorithm is

12:04

to apply ancillary features in this case

12:07

with the treatment response algorithm.

12:08

Ancillary features are diffusion restriction

12:11

or mild to moderate T two hyperintensity in an area

12:14

of uncertain mass like enhancement.

12:16

And the presence of these ancillary features can be used

12:19

to upgrade an equivocal lesion to a viable lesion.

12:23

So here's an example. This is a patient with, um, chronic,

12:26

um, HBV

12:27

and HCC, uh, status post treatment

12:31

to the right hepatic lobe,

12:32

but they've never had treatment to the left hepatic lobe.

12:35

And on one of the follow-up scans, we see this lesion, uh,

12:38

and there's sort of this ill-defined, um, enhancement,

12:41

and it's really sort of more visible on the, uh,

12:44

portal venous phase image

12:45

where you have a hypo enhancing new lesion here

12:48

in the left hepatic lobe.

12:50

Uh, this is what the T two

12:52

and diffusion weighted images look like.

12:53

You can see there's a little bit of, um, mild

12:56

to moderate T two hyperintensity as well

12:58

as some ill-defined, uh, DWI, um, diffusion restriction.

13:03

Okay, so this patient underwent taste

13:05

and you can see that the, the area here does again,

13:08

does not demonstrate arterial phase hyper enhancement.

13:11

There's sort of this ill-defined sort

13:13

of hypo enhancement on portal venous phase images associated

13:17

with this, uh, this capsular retraction.

13:19

Uh, so what does this mean? It was kind of unclear to us

13:22

and difficult to know whether this was, um,

13:24

equivocal disease or was it viable, non-viable.

13:28

Uh, in this case, the T two

13:30

and the diffusion really helped us.

13:31

Here. You have quite striking moderate T two hyperintensity

13:34

associated with that hypo enhancing area, as well

13:37

as really marked diffusion restriction.

13:40

So we use those ancillary findings

13:42

to upgrade this from an equivocal lesion

13:44

to an LRTR viable lesion.

13:46

And then you can see on the subsequent imaging,

13:48

five months later, this area has grown.

13:51

So it, it, it did bear out, it was really a viable disease.

13:56

Here's another case. Uh, a 68-year-old male five months

13:59

after, uh, taste, um, with this treated lesion.

14:03

Um, so you can see there's a lesion here on these pre

14:06

contrast images and on the art, uh, post contrast images,

14:09

there's sort of this thick rim of enhancement.

14:12

It's kind of a little bit difficult

14:15

to know is this just the smooth para lesional enhancement

14:18

that we expect after taste,

14:19

or is this more something more insidious?

14:23

Um, in this case, the diffusion helped us, um, on this,

14:27

these diffusion restricted images, you can see

14:28

that there's pretty significant diffusion restriction

14:31

associated with that rim of enhancement.

14:34

Uh, here in this case it w it helped us upgrade from

14:38

equivocal to viable disease.

14:42

So, uh, the last step, uh, in the non radiation algorithm,

14:45

um, if you are unsure between two, um,

14:48

treatment response categories,

14:49

choose the category reflecting the lower certainty in this

14:53

case LRTR equivocal.

14:56

Okay, so now we're going to the radiation algorithm.

14:59

Uh, and this is a little bit different from the

15:01

non radiation algorithm.

15:03

Um, uh, so here's step one

15:05

and the main difference between the radiation

15:07

and the non radiation based algorithm is

15:10

this category right here.

15:11

Uh, LRTR non progressing is new nomenclature

15:15

for the 2024 treatment response algorithm.

15:17

And it means mass like enhancement, which is stable

15:21

or decreased in size over time after local regional therapy.

15:24

The other categories are the same.

15:26

No mass, like enhancement means non-viable

15:29

and mass like enhancement, which is new

15:31

or increased in size over time is LRTR viable.

15:35

Um, step two, similar to with the non radiation algorithm,

15:39

um, any um, new or increased diffusion restriction

15:43

or mild to moderate T two hyperintensity enables you

15:46

to upgrade from non progressing to LR TR viable.

15:51

Step three, apply the T braking rules.

15:54

If you're unsure about two categories,

15:55

choose the one reflecting lower certainty in this case

15:58

LRTR non progressing.

16:01

So here's an example of a patient.

16:02

Uh, this is a patient with um, uh, cirrhosis obviously.

16:07

Um, this is a pre-treatment MRI.

16:08

You can see that the liver's nodular

16:10

in the right hepatic lobe.

16:11

There's an arterial enhancing lesion, uh,

16:14

which washes out on portal venous phase,

16:16

and you can see there's a delayed enhancing capsule.

16:18

This is, so this is an LR five

16:20

RADS five lesion pre-treatment.

16:22

So again, here's the pre-treatment arterial phase image.

16:25

The patient underwent Y 90 radio embolization

16:27

and here's the post-treatment image.

16:29

You can see that there's still this rim of enhancement

16:32

as well as some sort

16:33

of mass like enhancement within the lesion,

16:35

but it's clearly decreased since the um,

16:39

uh, pre-treatment imaging.

16:40

So this is LRTR, um, non, uh, LRTR non progressing.

16:46

Um, on the subsequent follow-up examination,

16:48

this is 35 months

16:49

after, um, treatment, you can see

16:52

that the patient has developed these characteristics, sort

16:54

of fibrotic changes in the treated segment.

16:57

Uh, in this case, the patient has developed liver capsular

16:59

retraction, um, as well

17:01

as intrahepatic biliary ductal dilatation.

17:05

Okay, so the rest of my talk is gonna be devoted to,

17:08

uh, practice cases.

17:09

Uh, so all of these are associated

17:11

with some audience response questions.

17:13

Uh, and we're gonna start out with some non radiation, uh,

17:16

some patients treated with non radiation based therapies

17:18

and then go on to radiation based therapies.

17:21

So this is practice case one.

17:23

Um, so this is a, um, sorry,

17:26

69-year-old patient with cirrhosis.

17:28

Um, there was a, um, lesion in segment two four centimeters,

17:32

um, and it was RADS five.

17:34

You can see that there's a segment two lesion

17:36

with arterial phase hyper enhancement wash out on portal

17:38

venous phase with a, uh, an enhancing capsule.

17:45

Uh, this is one month aftertaste.

17:47

I'll give you a second to look at these images.

17:54

Okay, so moving forward, what's the diagnosis here?

17:57

A-L-R-T-R, viable, B-L-R-T-R, non-viable, C-L-R-T-R,

18:02

equivocal and d LR or D-L-R-T-R non progressing.

18:07

I'll give you a few seconds.

18:14

All right, excellent. So, um, LRTR viable,

18:17

65% of you got that right.

18:19

It's LRTR viable.

18:21

Um, so you can't use non progressing on this case

18:24

because the patient was treated with taste.

18:26

So this is a non radiation based therapy.

18:28

Uh, so the non progressing category is not,

18:31

um, not appropriate here.

18:33

So here again are the post-treatment images,

18:35

one month aftertaste, you have nodular enhancement

18:38

around the periphery of the LE lesion here,

18:41

and then more superiorly here

18:42

and here this is mass like enhancement aftertaste.

18:45

So this is LRTR viable. Very good. Next case.

18:50

This is an 85-year-old, uh, female.

18:53

Um, and she has a 2.7 centimeter LRADs five observation here

18:58

in the right hepatic lobe.

18:59

You can see there's, um, diffuse arterial phase,

19:02

hyper enhancement, and then a capsule, um,

19:04

on the delayed phase images, uh,

19:08

this is a repeat MRI performed

19:10

after radiofrequency ablation.

19:12

I'll give you a few moments to look at these images here.

19:20

Okay, so what's the diagnosis here?

19:22

A-L-R-T-R, viable B-L-R-T-R, non-viable C equivocal

19:26

or D non progressing.

19:34

Uh, very good. Uh, the majority of you got LRTR non-viable.

19:37

I think that's correct. Uh, let's take a look.

19:42

So this is a patient treated with radiofrequency ablation,

19:45

so non radiation based therapy.

19:47

So here you're gonna either categorize it as non-viable,

19:50

viable or equivocal.

19:52

Uh, and then you can see that this treated area,

19:54

it's a little bit larger than the original lesion, uh,

19:58

which is expected.

19:59

Uh, but on these images you have a non-contrast arterial

20:02

phase, portal venous phase,

20:04

there's really no mass like enhancement.

20:06

So this LRTR non-viable practice case three,

20:12

there's a 53-year-old lady with alcoholic cirrhosis.

20:14

She has a 2.3 centimeter lesion in segment two of the liver.

20:19

Um, you can see that there's diffuse, uh,

20:21

or there's faint arterial phase, hyper enhancement.

20:24

And then on the portal, venous phase images, there's washout

20:26

and then an enhancement of a capsule.

20:28

So this is consistent with RADS five.

20:33

Uh, the patient underwent taste and this is the repeat ct.

20:37

So I'll give you a few moments to look at this image.

20:45

So what's the diagnosis here?

20:46

LRTR viable, LRTR, non-viable, equivocal or non progressing.

20:56

Okay, very good. The majority of you got LRTR non-viable.

21:03

So again, this is the repeat CT

21:05

performed one month after taste.

21:06

Here's the lesion. You can see that there is, um, a thin rim

21:11

of, uh, peripheral, um, enhancement,

21:14

which is not considered mass like enhancement.

21:17

So this is an expected finding aftertaste.

21:19

Um, this is not consistent with vi uh, viable disease.

21:22

This is LRTR non-viable.

21:26

Next case, 65-year-old lady

21:31

with, uh, hepatitis B, no cirrhosis,

21:34

and a segment eight LR five observation.

21:37

You can see this LR five observation here in the right

21:39

hepatic lobe on these arterial phase images.

21:42

This is the repeat MRI after radiofrequency ablation.

21:51

What's the diagnosis here?

21:53

Viable, non-viable, equivocal or non progressing.

22:01

Okay, uh, 40, 46% of you thought viable.

22:05

37% of you thought equivocal. Let's take a look.

22:11

So again, here's the, uh, treated area

22:13

after radiofrequency ablations,

22:15

this non radiation based therapy, um,

22:19

medial to the treated area.

22:20

There's this enhancement. So this isn't thin.

22:23

Um, this isn't a thin rim of peripheral enhancement.

22:26

This is more sort of nodular

22:28

and mass like than we've been seeing in other cases.

22:31

Um, so this is suspicious

22:32

and this is not an expected finding

22:34

after successful therapy.

22:36

This is LRTR viable. Good.

22:41

Next case. This is 70-year-old, uh,

22:45

with cirrhosis and an LR five observation in segment four.

22:48

A little difficult to see, but it's right here.

22:50

Um, you can see this artily enhancing, uh,

22:52

lesion in segment four of the liver.

22:56

Uh, and this patient underwent, uh, radiofrequency ablation.

23:00

Um, here is the treated lesion on arterial phase images,

23:04

portal venous phase images.

23:10

And then I have one more set of images to show

23:11

before I ask you to make a diagnosis.

23:14

Here's the diffusion weighted images and a DC map.

23:24

So what do you think LRTR viable, non-viable, equivocal

23:29

or non progressing?

23:35

Um, LRTR viable. 53% of you said lr TR viable?

23:38

Yep, that's good. Let's take a

23:40

look, Right?

23:45

So in this case, let me go back actually.

23:47

So in this case, after treatment,

23:49

there's this rim of enhancement.

23:51

It's thicker than we're used to seeing, um,

23:54

after successful therapy.

23:56

Um, and you can see that sort of persists on

23:59

the portal venous phase.

24:00

And then on this, um, this DWI image, you see this sort of,

24:05

um, um, uh, diffusion restriction that corresponds to

24:09

that rim of enhancement as well as, um,

24:12

a dark signal on the a DC map that really helped us

24:15

to upgrade this lesion from LR TR equivocal to LR TR viable.

24:19

And I think most of you got that next case,

24:23

radiation based therapy.

24:26

So this is an 88-year-old male with HCC.

24:28

You can tell there's a clear, um,

24:30

RADS five lesion here in the r hepatic lobe with sort

24:32

of diffuse arterial face hyper enhancement.

24:36

This is two months after Y 90 radioembolization.

24:42

Let's take a look at those for a second.

24:48

What's the diagnosis here?

24:49

Viable, non-viable, equivocal or non progressing.

24:58

Okay, so a little bit of disagreement here.

25:00

39% of you thought non progressing,

25:03

31% of you thought viable.

25:04

So let's take a look. Okay, so this is two months

25:09

after radio embolization.

25:11

And, um, sorry, let me go back real quick.

25:14

So this is the pretreatment imaging.

25:16

So you see diffuse this lesion

25:17

with diffuse arterial face hyper enhancement,

25:20

and this is two months after Y 90 radio embolization.

25:23

The lesion is basically unchanged in size.

25:25

There's no longer diffuse central enhancement.

25:28

There's nodular enhancement around the, um, lesion,

25:32

but it's much less than before.

25:34

And remember, this is radiation based therapy.

25:36

So the in summary, the degree, the amount

25:39

of MA like enhancement has really decreased

25:41

since the pretreatment scan.

25:43

So this is LRTR non progressing.

25:46

Remember, this is radiation based therapy.

25:48

So a, uh, persistent arterial phase,

25:50

hyper enhancement is allowed as long as it's stable

25:53

or decreasing in time, uh, over time.

25:55

LRTR non progressing.

25:59

Um, just to prove my point, this is um, um,

26:03

actually let's take a look at this six month,

26:04

uh, up, uh, scan.

26:06

This is a six months after Y 90 radioembolization.

26:09

The patient hasn't had any, um, additional therapy.

26:16

What's the diagnosis here?

26:18

LRT are viable, non-viable, equivocal or non progressing.

26:27

Okay? So, um, uh, kind of have all sorts

26:30

of different answers, viable, non-viable,

26:32

equivocal and non progressing.

26:33

Let's take a look. So again,

26:35

remember this is the same patient.

26:38

Um, this is now six months after Y 90 radioembolization.

26:42

So what we're seeing now is we've seen

26:43

that this lesion has shrunk.

26:45

Um, it's decreased in size, there's peripheral enhancement.

26:49

And this new finding here is this sort of

26:52

geographic wedge-shaped enhancement in the treated segment.

26:57

So, um, if you remember this, this sort of finding is due to

27:02

surrounding parenchymal changes as a result

27:04

of the radiation therapy.

27:06

Um, so this sort of geographic wedge-shaped enhancement

27:10

may be okay, um, and it may be an expected finding

27:13

after radiation, uh, based therapy.

27:16

So this is actually LRTR non-viable.

27:18

So the patient continues to have, um, no evidence

27:21

of viable disease.

27:24

Um, this is the follow-up scan.

27:26

Um, several months down the road

27:28

after that last scan I showed you,

27:30

and again, you have sort of more progressive findings

27:33

of fibrosis in the treated segment, right?

27:35

You have liver capsular retraction, wedge-shaped, um, uh,

27:39

parenchymal enhancement,

27:41

and you get the sense that there are these, um,

27:43

dilated intrahepatic ducts.

27:44

All of all these go along with radiation related fibrosis

27:47

and don't necessarily, um, uh, indicate viable disease.

27:52

Sometimes these cases can be very challenging.

27:55

Um, sometimes this, um, in this, um,

27:58

enhancement can be very difficult to distinguish between

28:01

new infiltrative disease.

28:03

Um, and I acknowledge that it can be very challenging.

28:05

And in those cases, I think all we can do is really follow

28:07

them over time to see if, um, more disease develops

28:12

or if the patient sort of develops this situation

28:15

where you have shrinkage and fibrosis of the treated area.

28:20

Okay, next case, radiation.

28:24

Um, so here's a patient

28:25

with a RADS five lesion here in the right hepatic lobe.

28:28

You see arterial phase hyper enhancement

28:29

washout on the portal venous phase.

28:33

Uh, this is six months after Y 90 radioembolization.

28:41

Um, so what's your diagnosis?

28:43

Um, LRTR, viable, non-viable, equivocal

28:48

or non progressing.

28:54

Okay, uh, some of you thought viable, some

28:56

of you thought non progressing.

28:57

Let's take a look. Um, let me go back.

29:01

Okay, so here's is a pre-treatment, um, scan.

29:05

You have diffuse arterial phase hyper enhancement in

29:07

this r hepatic lobe lesion.

29:09

Here's the post-treatment scan.

29:11

Um, and then here again, we'll see the post-treatment scan.

29:14

Um, you have, you still have this lesion,

29:16

you still have mass like enhancement.

29:18

It's no longer diffuse

29:19

and it's clearly decreasing, uh,

29:21

since the pre-treatment scan.

29:23

Um, this patient was also noted

29:25

to have downtrending A FP at this time.

29:27

So this is LRTR non progressing.

29:32

Uh, and this is a, a total of 15 months.

29:34

Um, after tear in the same patient,

29:36

you can see these progressive fibrotic changes.

29:39

The lesion has continued to shrink,

29:41

although there's persistent arterial phase, hyper

29:43

or mass like enhancement.

29:45

Uh, it's continued to decrease since the prior examination.

29:48

And you have these findings of liver fibrosis

29:50

with capsular retraction in the treated segment.

29:53

Okay, next case radiation.

29:57

Um, I don't have pretreatment images on this one.

30:00

Uh, this is an HCC with Y 90 embolization on, uh,

30:04

June, 2019.

30:06

So here's the scan, uh, here's the area of interest.

30:09

Here's the scan from, uh, March, 2020, uh,

30:12

follow up in June, 2020,

30:16

and then subsequent follow up January, 2021.

30:22

So take a look at that

30:24

and what do you think the diagnosis is on the final

30:26

scan in 2021?

30:28

LRTR, viable, non-viable, equivocal or non progressing?

30:38

Okay, LRTR viable, 90% of you said that,

30:41

and I think you are absolutely correct.

30:43

So in this case, um, on the immediate follow-up,

30:47

the patient has arterial phase hyper

30:48

enhancement in the treated area.

30:50

That may be okay,

30:51

but you can see over time this, um,

30:54

arterial hyper enhancement is clearly increasing the lesion

30:57

this observation is, is increasing in size

31:00

until the 2021 examination.

31:02

So this is LRTR viable, very good.

31:09

Another case, this is a 77-year-old male, Hep B cirrhosis,

31:13

HCC, he's had a history of multiple lesions treated

31:16

with chemo embolization and microwave BL ablation.

31:19

He has this new arterially enhancing lesion in segment eight

31:22

of the liver here in the central liver

31:24

with arterial phase hyper enhancement and washout.

31:26

This is a RADS five lesion.

31:29

The patient underwent Y 90 trans arterial radio embolization

31:32

and had a repeat MRI one month

31:34

after, uh, the procedure, there's a little bit

31:37

of arterial phase, hyper enhancement on the

31:39

medial aspect of the lesion.

31:44

This is the associated, uh, diffusion weighted imaging

31:47

and, uh, T two weighted imaging.

31:51

Okay, so now we have a follow-up examination.

31:54

Six months after the last one I showed you.

31:56

This area of sort of enhancement medial

31:59

to lesion looks like it's increased in size a bit.

32:05

And here's the, um, here's the evolution

32:08

of the diffusion restriction and T two weighted imaging.

32:12

So here you can see, uh, this is immediately post-treatment.

32:15

This is six months after treatment.

32:17

Here's immediately post-treatment on the left.

32:20

Here's six months after treatment on the right.

32:26

So what do you think on the most recent examination,

32:29

LRT are viable, non-viable, equivocal or non progressing?

32:38

Great. 66%

32:40

of you said LRT are viable and I think that's correct.

32:43

So you can see here clearly in addition to the growing, um,

32:47

arterial phase, hyper enhancement,

32:49

you have increased T two signal along the medial aspect

32:52

of the leg, or I'm sorry, increased diffusion restriction

32:55

along the medial aspect of the lesion.

32:56

Here it's growing from this scan to this scan

32:59

and also this, um, this mild

33:02

to intermediate T two signal intensity

33:04

hyperintensity is also increasing.

33:07

Here's the immediate post-treatment

33:08

and then the subsequent examination.

33:10

You can see it's increasing here medially.

33:12

So this is LRTR viable very good.

33:14

And then you can see that on the follow-up examination,

33:17

four months after that it continues to grow.

33:19

So this is clearly a viable disease.

33:23

Okay, next case radiation.

33:27

Here's a 65-year-old with cirrhosis

33:29

and HCC, this is the pre-treatment scan.

33:31

So you have a RADS five lesion in the right hepatic lobe

33:34

with arterial phase,

33:35

hyper enhancement washout, and a capsule.

33:39

The patient underwent, um, radio embolization with Y 90.

33:43

And um, these are the follow-up scans.

33:46

This is in, um, October, 2023 and then March, 2024.

33:52

So here's the pre-treatment

33:55

and then here's a post-treatment.

33:59

So I'll give you a few moments to look at that.

34:06

What's the diagnosis on the most recent scan?

34:08

Viable, non-viable, equivocal or non progressing?

34:17

Uh, okay, uh, the majority you've got got it.

34:19

LRTR non progressing. 56% of you. Let's take a look.

34:23

So, um, here are the post-treatment images after Y 90.

34:27

You can see that there's still some arterial phase,

34:30

hyper enhancement within the treated area,

34:32

but it's decreased since the pre-treatment examination.

34:36

And this is radiation based therapy.

34:38

So this is LRTR, non progressing. Very good.

34:43

Next case. Uh,

34:46

and here I apologize, I don't have the pretreatment imaging,

34:48

uh, but this is a 79-year-old with alcoholic cirrhosis

34:51

and HCC, uh, after trans arterial radio embolization.

34:55

Here is the scan on April, 2021,

35:00

July, 2021.

35:02

And then the follow-up scan. This is November, 2021.

35:06

What do you think about the most recent scan at RTR, viable,

35:12

non-viable, equivocal or non progressing?

35:20

Okay, so this is, this is a challenging case,

35:22

but let's take a look.

35:24

So this is a 79-year-old alcoholic cirrhosis,

35:28

HCC post tear.

35:30

The treated area is here in the dome.

35:32

Um, in April, you don't really have much

35:35

arterial face, hyper enhancement.

35:36

Maybe if you few flex here

35:37

and there, that really isn't changing, uh, over time.

35:41

Um, and here by 11 20 21 really,

35:45

there's not really any, um,

35:48

significant arterial phase hyper enhancement.

35:51

So this one we call LRTR non-viable.

35:56

Okay, so same patient again, this is the um,

36:00

November 21, 21 scan.

36:03

Here's the July, 2023 scan.

36:06

This patient was treated with Y 90 radioembolization.

36:10

What do you think the diagnosis is here?

36:12

LRTR, viable, non-viable, equivocal or non progressing

36:22

viable, 83% of you said viable, and I think that's correct.

36:25

So you have this patient who's had this long period

36:28

of stability, uh, right after Y 90 therapy

36:31

and all of a sudden on um, uh, July, 2023,

36:34

they've developed these new nodular mass like areas

36:37

around the periphery of the treated Observation, uh,

36:40

this is clear, um, LRTR viable disease, so very good.

36:47

Uh, next case radiation.

36:50

This is an 85-year-old male with HCV cirrhosis

36:52

and a 5.6 centimeter RADS five lesion at the junction

36:56

of segment six and seven.

36:57

You can see this enhancing lesion washout,

37:00

it's clearly LRADs five.

37:03

Um, the patient has undergone Y 90

37:05

and this is a follow-up imaging four months later.

37:08

Um, it's not easy to tell

37:09

unless, um, if you don't have direct comparison,

37:11

but the lesion has decreased in size to 5.1 centimeters.

37:14

Here's the pre contrast images

37:16

and the arterial phase images here on your right.

37:21

So what do you think about this viable, non-viable

37:25

equivocal or non progressing?

37:32

Okay, 61%

37:33

of you said non progressing and I think that's correct.

37:36

Um, so this is four months after Y 90.

37:38

Uh, there was a diffusely enhancing lesion

37:40

and it, it has decreased in size to 5.1 centimeters,

37:44

even though there's persistent arterial phase,

37:46

hyper enhancement, it's decreasing.

37:48

So this is LRTR non progressing.

37:53

Uh, next case radiation therapy,

37:58

66-year-old male with hepatitis B.

38:00

You can see that there's an arterial hyper enhancing lesion

38:03

here in the right hepatic lobe.

38:07

Uh, that lesion is associated with some, um, mild

38:10

to moderate T two hyperintensity as well as some, um,

38:14

marked diffusion restriction.

38:17

So this patient underwent, um, Y 90 radio embolization.

38:23

So here's the pre-treatment scan on your left

38:25

and here's the post-treatment arterial

38:27

phase scan on your right.

38:31

What do you think? LRTR viable, non-viable,

38:34

equivocal or non progressing.

38:42

Okay, um, um, different, also different answers.

38:48

So, uh, I'll tell you this is a challenging case, right?

38:51

Pre on the pre-treatment you have this, um, lesion with sort

38:55

of diffuse arterial face hyper enhancement

38:57

here on the post-treatment scan.

38:59

You have this sort of geographic enhancement here in

39:02

the, in the treated segment.

39:04

The observation itself looks a little bigger than before.

39:07

You don't have the diffuse enhancement.

39:09

You have these sort of heterogeneous areas

39:11

of arterial phase enhancement within the lesion.

39:14

We were kind of unsure. Um, we suggested non progressing.

39:19

Our impression was that the degree

39:21

of arterial phase hyper enhancement is

39:22

decreased after treatment.

39:25

Um, and this is six months later

39:27

with no additional treatment.

39:34

What do you think about that? LRTR viable, non-viable,

39:39

equivocal or non progressing?

39:47

Yeah, so, um, most of you're split

39:49

between non-viable and non progressing.

39:51

So let's look at these images.

39:53

So again, this is six months later, no additional treatment.

39:56

I would argue that this treated area,

39:58

there's just not really any mass like enhancement.

40:00

There's this rim of peripheral enhancement.

40:04

There's also this geographic enhancement in the treated

40:07

segment, um, associated with what looks like some fibrosis,

40:10

some capsular retraction,

40:12

possibly some biliary ductal dilatation.

40:14

These are sort of expected findings, um, with the evolution

40:17

of radiation fibrosis.

40:19

Um, so given the evolution of this lesion over time,

40:23

we categorize this as LRTR non progressing.

40:27

Um, yeah, I think,

40:29

I think you could go either way on this one.

40:31

LR TR non progressing

40:32

or LRTR non-viable, um, I think would be, um, acceptable.

40:42

Okay, 66-year-old with cirrhosis

40:45

and an LR five observation

40:47

after, uh, trans arterial radioembolization.

40:51

So this, these are both post-treatment, uh, images, uh,

40:55

this is the pre contrast on your left, uh,

40:57

post contrast on your right.

41:00

Uh, and then this is two years later, uh, March of 2023.

41:04

The patient hasn't had any additional treatment,

41:09

so I'll give you a few moments to look at that.

41:17

What do you think here? LRTR viable.

41:20

LRTR, non-viable equivocal or non progressing?

41:28

Non-viable. Yeah, I think you are right.

41:31

So, um, here on this follow up examination,

41:35

really no mass like enhancement in the treated observation.

41:38

There's geographic enhancement in the treated segment

41:41

associated with some findings of fibrosis.

41:43

Um, there's no evidence of viable

41:44

mass like enhancement here.

41:46

This is LRTR non-viable.

41:49

Okay, radiation based case, 69-year-old with alcoholic,

41:54

uh, cirrhosis and HCC after tear.

41:57

This is the pretreatment imaging here.

41:59

So you can see this big mass here in the right hepatic lobe

42:02

associated with arterial phase, hyper enhancement

42:05

and moderate T two.

42:07

Um, uh, hyperintensity, here's the post-treatment image.

42:13

I'll give you a few moments to look at that.

42:19

Okay, so what's the diagnosis here?

42:21

LRTR, viable, non-viable, equivocal

42:25

or non progressing,

42:31

non-viable or non progressing.

42:33

Uh, where the majority of the

42:34

answers, and I think that's correct.

42:35

This is the challenging case.

42:37

Um, it looks like in the, uh, treated area really has, um,

42:42

lost all of its arterial phase, hyper enhancement.

42:45

Um, there's a little bit of sort of geographic enhancement

42:47

around the treated area in the treated segment,

42:50

but I think really in the, um, treated area,

42:53

there's no more mass like enhancement.

42:55

We call this LRTR non-viable.

42:59

Okay, I have two, two special cases and

43:01

before I wrap up, let's uh, take a look at this first one.

43:04

Uh, this is an age, this is a patient

43:06

with hepatocellular carcinoma.

43:08

He's undergone surgical resection.

43:09

So he underwent a, a segment five six resection

43:12

and he has this area along the surgical margin, uh,

43:16

which demonstrated some sort of faint arterial phase,

43:19

hyper enhancement with some, um, mild washout.

43:24

Uh, that area is associated with the MT two signal

43:27

and some increased diffusion restriction.

43:30

So what's the diagnosis here?

43:31

Viable, non-viable, equivocal, non progressing,

43:36

or we can't use the LRTR algorithm in this case

43:40

because this patient, patient was treated with surgery.

43:47

Okay. Um, so answer split between viable

43:51

and we can't use the LR TR algorithm in this case.

43:54

Um, the reason I showed this case is

43:56

to highlight a change in

43:58

or a clarification in the new LR

44:00

treatment response algorithm.

44:02

They do clarify that we can use the algorithm to, um,

44:06

assess patients who have been treated

44:08

with surgical resection.

44:09

So in this case this would be LRTR viable.

44:11

So you can use the LRTR uh,

44:13

treatment algorithm in this case.

44:18

Uh, and now this is a second special case.

44:22

So this is HCC.

44:23

This patient has had TAs remotely and now has had recurrence

44:27

and now they're on a clinical trial.

44:29

They're being treated with systemic therapy in this case,

44:31

case lenvatinib and nivolumab.

44:34

So here is the pretreatment scan.

44:37

You can see there's this observation here in the liver dome

44:40

with all this, um, sort of peripheral nodular enhancement.

44:44

This is the pretreatment examination and this is

44:46

after a few months after systemic therapy, a few months

44:50

of systemic therapy after LA Leib

44:52

and nivolumab, uh, let me go back.

44:57

Okay, I, that's fine.

44:59

Um, so what do you think LRTR non-viable, viable,

45:02

non-viable, equivocal, non progressing

45:05

or here we can't use the LRTR algorithm in this case,

45:14

right?

45:15

So, um, answers are split between non-viable.

45:18

Some of you said we can't use the LRTR algorithm in this

45:20

case, and in this case it's very tempting

45:22

to wanna use the LRTR algorithm, right?

45:25

Um, here's the pretreatment scan

45:27

and you can see all this mass like enhancement has basically

45:29

disappeared after, um, use of the systemic therapy.

45:34

Um, but the LRTR, the algorithm, um, does clarify

45:38

that in patients who are treated with, um,

45:40

both systemic therapy

45:42

and local regional therapy, they discourage the use

45:45

of the RADS treatment response algorithm.

45:47

Instead they favor, uh, the use of EM r assist

45:50

and other, um, um, um, assessment protocols

45:55

that you may use at your own institutions.

45:58

Okay, so that's all I've got in summary.

46:01

So the RADS treatment response algorithm has been

46:04

revised for 2024.

46:05

The major changes that there's separate decision pathways

46:08

for radiation and non radiation based therapy.

46:11

So it's critical to know what sort

46:13

of local regional therapy your patient has undergone, uh,

46:16

before you evaluate the images.

46:18

Um, T two weighted images

46:19

and diffusion weighted images are useful ancillary features

46:22

in assessing treatment response.

46:24

And then patients who are on systemic therapy should be, uh,

46:26

evaluated with other algorithms.

46:30

And that's all I have. Thank you so much.

46:34

Thank you so much for that case review.

46:36

We really appreciate it and for everyone else

46:38

for participating in the polling,

46:39

if you've got any questions,

46:41

we are opening the floor now for those.

46:43

Um, go ahead and pop those into that Q

46:45

and A box so we can get through them all.

46:50

So far no questions have come in,

46:52

but sometimes it takes a second

46:53

or two, so we'll give it a moment.

46:58

Uh, so the question is, why is it a different pathway

47:00

for radiation and non radiation pathways?

47:03

So, um, the, this is a new, um, this is a new, um,

47:08

sort of feature in the 2024, uh,

47:11

RADS treatment response algorithm.

47:13

Um, in the previous algorithm, everything was either

47:17

non-viable, viable or equivocal.

47:20

And, um, because radiation has this slow evolution

47:24

of changes, um, um, I think the authors felt that a lot

47:28

of patients were getting unnecessary re-treatment if we saw,

47:33

um, persistent arterial phase,

47:35

hyper enhancement after treatment.

47:36

But in reality, persistent arterial phase, hyper enhancement

47:40

after treatment as long as it's stable

47:42

or decreasing, doesn't mean

47:43

that the treatment was unsuccessful

47:45

and that the patient needs additional re-treatment.

47:48

So the new algorithm was changed

47:50

to introduce this non progressing category, um, so

47:54

that patients don't undergo unnecessary re-treatment.

47:59

Uh, second question.

48:02

Uh, can you explain how to differentiate

48:04

between LRTR non-viable versus LRTR non

48:07

progressing post-radiation?

48:09

Yeah, so

48:10

after treatment, if the, um,

48:14

MAs like enhancement completely disappears,

48:16

that's LRTR non-viable.

48:19

If the MAs like enhancement after treatment persists,

48:22

but it's stable or decreasing when compared

48:25

to the pre-treatment examination that's non progressing.

48:31

Um, okay, very good.

48:34

Do you assign LRTR when pretreatment imaging

48:37

is not available?

48:39

Um, I don't, I usually do not.

48:42

Um, I think I would evaluate it on, on a case by case basis.

48:46

Um, uh, generally speaking,

48:49

when there's no pretreatment imaging available, um,

48:53

I usually shy away from uh, uh,

48:55

use assigning an LRTR category.

49:02

Uh, okay. Uh, there's a question in the chat.

49:05

Do you need MRI and CT

49:07

or can you use this for CT with contrast only?

49:10

No. Um, the treatment response algorithm can be used

49:13

with MRI or ct.

49:14

Um, so you don't need both.

49:16

Uh, you can have one or the other.

49:19

Does PET have a role in post-treatment evaluation

49:22

and where does it fit?

49:23

So the LRTR response algorithm

49:26

after local regional therapy does not, uh, specifically,

49:30

um, include pet.

49:32

Um, and I, um,

49:35

typically at our institution we do not use PET

49:38

for these situations.

49:40

Um, I suppose it's possible in very, um, um, equivocal

49:44

or very difficult situations that someone may,

49:46

uh, may use a pet.

49:47

But generally speaking, we prefer to, um,

49:50

follow cases over time with MRI, uh,

49:52

and CT rather than use pet.

49:58

Hey, I think we got all the questions.

50:00

Thank you so much. Awesome.

50:01

Thank you so much. Yeah,

50:03

appreciate it and appreciate that.

50:04

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