0:02

Hello and welcome to Noon Conferences hosted by MRI Online.

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3 00:00:05,280 --> 00:00:06,750 In response to the changes happening around

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the world and the shutting down of in-person

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events, we have decided to provide free daily

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noon conferences to all radiologists worldwide.

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Today we're joined by Dr. Zahra Kassam.

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After completing medical school at the University

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of Alberta, she finished her residency training

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at Western University and her fellowship

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at Body Imaging at Stanford University.

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She's an Associate Professor of Medical Imaging and

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Oncology and currently serves as Division Head of Body

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Imaging at Western. Dr. Kassam's clinical and research

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interests are in abdominal and pelvic MRI, rectal

0:32

and prostate cancer MRI, hybrid imaging, hepatic

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fibrosis, and MR Elastography. Reminder, there will be

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time at the end of this hour for a Q and A session.

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Please use the Q and A feature to ask

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all of your questions and we'll get to

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as many as we can before our time is up.

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We'll also be using the polling feature today.

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So be on the lookout for that.

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And that being said, thank you

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so much for joining us today.

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I will let you take it from here.

0:53

Hi everyone.

0:54

Uh, thank you for joining us today.

0:56

It's my pleasure to, um, be here with all of you.

0:59

And, um, I'm gonna be talking about something

1:01

that is, uh, very near and dear to my heart.

1:04

Um, I'm sure many of you are involved in some sort

1:08

of, um, multidisciplinary, uh, rounds or conferences.

1:11

So we're gonna be talking

1:12

about the GI Tumor Board today.

1:15

Um, and I'm gonna share with you some of the

1:16

pitfalls, pearls, and lessons I've learned over time.

1:20

And, um, hopefully you find this

1:22

beneficial for your practice as well.

1:23

Okay, so here we go.

1:29

All right, so the objectives for today are to,

1:32

um, review some of the commonly encountered

1:34

diagnostic challenges in GI oncology imaging.

1:38

We'll talk specifically about some of the pearls

1:40

and pitfalls with staging, and I'm going to try

1:43

and integrate, um, some of the surgical pearls that

1:46

I've learned over time from my colleagues, and I'm

1:49

sure many of you who do this, um, are also aware

1:52

that one of the benefits of these conferences is.

1:55

The learning that occurs from

1:57

a multidisciplinary setting.

1:58

So we learn a lot of things in radiology that we

2:01

probably didn't know in medical school, but they're

2:03

very unique to our own specialty, and we don't

2:06

necessarily learn about, um, the important things

2:09

that the referring doctors need to know when they're

2:11

reading our reports until we're in the room with them.

2:14

So I'm gonna try and share with

2:15

you some of that information.

2:16

And we are going to have, um, polling

2:18

for a lot of, uh, the talk today.

2:20

So I'd encourage you to please vote,

2:22

um, using the audience response system.

2:24

Um, and we will be going through

2:25

some cases together as well.

2:29

So, uh, the GI Multidisciplinary Conference,

2:32

multidisciplinary case conference, as we call it, is

2:34

now an expected responsibility in diagnostic imaging.

2:38

So it used to be something new,

2:39

something you'd volunteer for.

2:41

Um, but over time, and it's happened in

2:44

a very short period of time, it's now an

2:46

expected duty for, um, radiologists that work.

2:50

Primarily at academic centers, but

2:51

also in community hospitals as well.

2:53

So instead of being concentrated at academic

2:56

centers, now this responsibility is sort of

2:59

filtering out and becoming much more widespread.

3:01

So I think anybody now training in diagnostic imaging

3:04

is going to be exposed to these rounds and will have

3:07

an expectation to participate in them at some point.

3:10

And there is an increasing body of evidence

3:11

showing that these rounds lead to improved

3:14

clinical outcomes for our patients as well.

3:17

So here's a paper, um, published by the University

3:20

of Toronto just down the road from me, uh, a

3:23

few years ago, uh, that looked at the effect of

3:25

multidisciplinary cancer conferences on the treatment

3:28

plans for patients with primary rectal cancer.

3:31

Um, and now they had, um, just a few patients,

3:34

I believe there were 75 in total, 42 were

3:37

discussed at the MCCs, and they found

3:39

that the MCC discussion led to a whopping.

3:43

30% change of the initial treatment strategy.

3:46

So of 42 patients included, seven of them

3:49

had their treatment plan changed to a primary

3:52

surgery, five of them changed to preoperative,

3:55

uh, chemoradiation or just chemotherapy.

3:57

And 40% of those changes were based on the discussions

4:00

of imaging at the multidisciplinary conference.

4:03

So just the report itself provides

4:05

information, but having that setting to

4:07

discuss, um, other factors that may not.

4:11

Be available to the reporting radiologist seems to

4:13

have a dramatic change on the overall interpretation

4:17

and development of a treatment plan for patients.

4:19

So I'm sure those of you who are part

4:21

who participate in these rounds also

4:23

are anecdotally noticing this trend.

4:26

I know myself when I go to these rounds, um, I also

4:29

notice that there, there may be either mild, um,

4:33

minimal or significant differences in the overall

4:35

treatment plan when I'm staffing these rounds.

4:38

So the bottom line is these rounds are

4:40

here to stay, um, and we need to be

4:42

involved and invested as radiologists.

4:46

Alright, so let's move on to some cases.

4:48

So the first case is a 71-year-old male.

4:51

He had a recently visualized sigmoid

4:53

mass on endoscopy and no prior imaging.

4:58

So I'm going to share with you select images from

5:01

the CT scan that was done following the endoscopy.

5:04

So remember the history is recently visualized

5:06

sigmoid mass, and I'm gonna just point out that

5:09

mass for you and I'd like you to just take a

5:12

look at these images and then answer a question.

5:15

So I'll give you a few seconds

5:16

here to review these images.

5:19

And the question is going to be, which

5:21

conclusion would you put in your report?

5:23

So as you're looking at these images, think about

5:25

what your conclusion in your report would be.

5:30

Okay.

5:31

So let's go to the questions.

5:32

Which conclusion would you put in your report?

5:35

And there's no correct answer here.

5:36

I just am interested in seeing

5:38

what people would say about this.

5:43

And I'll just go back on my slide again, just

5:46

in case you wanted to look at the images.

5:49

I'll give you another few seconds to vote here.

5:54

They are pretty long stems to read.

5:57

Okay, so, um, here are our results.

6:02

So majority of the group chose an answer C, which

6:06

was an annular sigmoid mass and cystic, or

6:09

solid pancreatic lesions, which require further

6:11

workup to exclude a second primary malignancy.

6:15

So well done.

6:16

So this is just a warmup question, um,

6:20

and we will come back to, uh, why C

6:23

is the best answer in just a moment.

6:25

But first, let's, uh, answer this question.

6:27

Which recommendations should we make

6:29

based on the imaging findings here?

6:33

So the choices are CEA, CA 19-9, endoscopic

6:37

ultrasound, genetic counseling, or all of the above.

6:42

All right, so the majority of

6:43

people said all of the above.

6:45

That is the correct answer.

6:47

So well done.

6:47

So this patient actually has two independent

6:50

primary tumors, um, pancreatic and colonic,

6:54

and um, actually has Lynch syndrome.

6:56

So what are the teaching points or

6:58

learning points we can take from this case?

7:00

Well, as we all know, cancer is very common

7:03

and in patients with multiple lesions in

7:05

unusual sites, we need to consider a metastatic

7:08

disease as well as separate primaries,

7:10

especially if the location and morphology of

7:13

the second lesion is atypical for a metastasis.

7:16

So.

7:17

As we, as we know, we, we all, um,

7:19

come across this during our practices.

7:22

Um, the way that you actually come up with a

7:24

conclusion and dictate it in your report can

7:27

trigger a totally different management plan.

7:29

So in this case, a new biopsy and

7:31

a different approach to therapy.

7:33

Um, were actually part of the

7:34

management plan for this patient.

7:36

Um, second teaching point is that tumor markers can be

7:39

very helpful to narrow the differential diagnosis, and

7:42

I always try to teach our residents and fellows that

7:45

we should go from least invasive to most invasive.

7:47

Um, so before the biopsy is performed,

7:50

it's always helpful to get tumor markers

7:52

to just guide us down the appropriate path.

7:55

And genetic counseling should be

7:56

considered for, um, family members.

7:59

In a patient like this.

8:00

It wouldn't be the responsibility of the

8:02

radiologist necessarily to, um, arrange

8:05

for that, but it is important that we're

8:07

aware of, um, the genetic relationship here.

8:10

So well done.

8:13

Okay, so the second case is a 67-year-old female

8:17

with a rectal mass and at biopsy, um, there was

8:21

a tubulovillous adenoma with high-grade dysplasia

8:24

involving 20 to 25% of the luminal circumference.

8:28

And then the patient presented to

8:30

our MRI department for staging.

8:34

Okay, so these are the images that were acquired.

8:36

So we've got multiplanar, uh, T2-weighted

8:39

images, high resolution of the lesion.

8:44

So I'll let you look at that,

8:50

and I'd like to ask you how

8:51

you would stage this tumor.

8:53

So I'll just put the slide back up

8:54

so you can have that for reference.

8:57

So how would you stage this tumor?

8:59

And it's challenging because

9:01

we only have three images here,

9:06

so the choices are T2, T2 versus early T3.

9:10

T3 and T4.

9:14

Okay, so the majority of us said T3, so

9:18

I'm glad we are showing you this case 'cause

9:20

there's a very important learning point here.

9:25

All right, so I'm gonna go through these images again.

9:27

So let's just review briefly how

9:29

we plan our rectal cancer cases.

9:31

So, um, the recommendation is to always start with

9:34

a sagittal T2-weighted image, um, localize the

9:37

tumor and then obtain axial oblique and coronal

9:41

oblique images relative to the tumor and the lumen.

9:45

So you can see in this case we planned

9:47

our coronal oblique according, uh, by

9:50

drawing a line parallel to the lumen.

9:52

And we received this image here and

9:55

then we went, um, perpendicular to that.

9:58

Got our axial oblique T2-weighted image.

10:01

So what's interesting about this case here is the

10:04

tumor actually, um, pushes out the lumen of the

10:08

small bowel, or sorry, the lumen of the rectum.

10:11

And, um, you can see that the muscularis

10:13

propria in this case is actually preserved.

10:19

So here's the muscularis propria.

10:22

And, um, this case actually was staged as

10:24

a T3, like, uh, most of you said.

10:27

And it's because the tumor was actually

10:29

pushing out the muscularis propria

10:31

on that one axial oblique image.

10:33

And that was measured as, um,

10:35

invasion beyond the muscularis.

10:38

But if you go back to the coronal.

10:40

You can actually clearly see

10:42

that the muscularis is preserved.

10:44

So, um, unfortunately we have kind of been,

10:47

um, subject to an error that occurs quite

10:51

commonly that's out of our control just because

10:53

of the anatomic variation of the rectum.

10:56

So we're gonna talk about that in a minute.

10:58

So, um, here we have to be very careful that

11:00

we look at all three planes and judge, um, the

11:04

muscularis integrity on all of those planes.

11:07

So in this particular case, we probably should have

11:09

done what I like to call a double oblique view.

11:12

So, um, obtain one oblique view in the

11:14

coronal plane and then a second oblique

11:17

view relative to that image to, um, actually

11:20

have the muscularis propria in profile.

11:23

So that's what I call a double oblique view.

11:28

Actually this, um, was a T2 tumor.

11:31

So the teaching points here are that the

11:34

position of the rectal lumen is quite variable

11:36

between patients and each case requires careful

11:40

planning and dialogue with the technologist.

11:42

So, um, when I'm reporting these

11:43

cases, I'm right next to the scanner.

11:46

Um, we have, uh, dialogue going on,

11:49

um, either directly with the MRI

11:51

technologist or over the phone nowadays.

11:54

Um, but every single case has to be

11:56

reviewed by the radiologist before

11:58

the axial oblique images are obtained.

12:02

And the ideal angle should be perpendicular

12:05

both to the tumor and to the lumen.

12:07

And sometimes the plane of the tumor and

12:10

the plane of the lumen are a little bit

12:12

variable and they're not exactly the same.

12:14

So this is one example of that.

12:16

So some cases may require a double oblique

12:19

approach, or if you're not able to do that,

12:21

at least look at all three planes to assess

12:23

the integrity of the muscularis propria.

12:26

And also we wanna keep in

12:28

mind the endoscopic findings.

12:30

So we wanna try and make sure that, um, our MRI

12:33

findings are concordant as much as possible with

12:35

the endoscopic findings, that they make sense.

12:38

So in this case.

12:40

Um, a large polyp was actually, um, diagnosed

12:43

histologically, and sometimes the pathology is

12:45

incorrect, but at least we should go back and look

12:48

at the pathology and the endoscopy, um, findings

12:52

to make sure that there's not a huge discrepancy.

12:54

So, uh, we always recommend to those

12:57

that are learning that they review the

12:59

endoscopic findings for each and every case.

13:06

Okay.

13:06

So we'll move on to case number three, and

13:09

if anybody has questions, um, at any time,

13:11

please do enter them into the Q and A.

13:17

I know I have one question here that says, how

13:19

do we measure the mesorectal extension exactly.

13:22

Is it from the outer margin or the inner margin?

13:27

Um, so.

13:30

Let me actually see if I can, you know,

13:32

what, maybe we will leave that for the end.

13:34

Um, and Ashley, I'll just maybe

13:36

get you to record that question.

13:38

So we'll move on to case number three.

13:41

So this is a 48-year-old female with T3 N2 M0

13:45

high rectal carcinoma.

13:51

The original CT was negative

13:52

for distant metastatic disease.

13:55

She underwent chemoradiation and surgery,

13:58

uh, just because of the high stage

14:00

of her tumor, but it was localized.

14:03

And now she presents two weeks after her surgery, her

14:06

low anterior resection with left-sided abdominal pain.

14:10

So for reference, I'm just showing you preoperative

14:13

CT images so we can see that there's a, a thick,

14:16

um, tumor in the rectum and there's several

14:18

tumor nodules and nodes in the mesorectal fat.

14:21

But now the problem that the patient is facing

14:23

two weeks post-op is left-sided abdominal pain.

14:27

So here are the postoperative images.

14:29

So this is two weeks after resection and anastomosis,

14:33

sorry, six weeks after resection.

14:35

She's had abdominal pain for about four weeks now.

14:38

So I'd like you to look at these images and then,

14:41

uh, we'll just put the poll up for the question.

14:48

So what do you think the most

14:49

likely diagnosis is in this case?

14:52

So we've got four choices here, splenic infarct,

14:55

necrotic metastasis in the gastro-splenic

14:57

ligament, omental infarct, and hematoma.

15:03

So just take a few seconds here to

15:04

look at these images and please vote.

15:10

Okay.

15:10

So let's see how we did.

15:12

Okay, so the majority of the group, so we're

15:14

kind of all across the board here, majority

15:16

of the group, um, thought this was a necrotic

15:19

metastasis in the gastro-splenic ligament.

15:21

And I don't blame you for thinking that because, um.

15:25

It's very, it has a very, um, ugly appearance.

15:28

So it has rim enhancement.

15:29

The gas is kind of in the middle.

15:31

There's an air-fluid level.

15:33

Um, it just looks ugly.

15:34

Um, so remember that the pre-op staging scan was

15:37

negative, so, um, necrotic metastasis, although

15:41

it's possible, it would be quite unusual to

15:43

have that at the six-week post-surgical mark.

15:46

So let's look at what this actually is, and

15:48

this is a good learning point for me as well.

15:51

So this actually turned out to be a hematoma.

15:54

Now how does that happen and how does that work?

15:56

So this was actually, um, learning about this

15:59

for me in particular, uh, really opened my eyes

16:03

as to what we need to know as radiologists.

16:05

So, um, I'm sure all of you are sitting there

16:07

thinking, how is this possibly a hematoma?

16:09

So we will talk about that.

16:10

So this patient.

16:11

Um, had a postoperative hematoma following splenic

16:15

flexure mobilization, or as the surgeons call it, SFM.

16:19

Um, and I have a diagram here just outlining

16:22

what happens, um, during that procedure.

16:25

But first, let's discuss what it actually is.

16:27

So splenic flexure mobilization is a crucial step in

16:31

all left-sided colorectal surgeries, particularly

16:34

laparoscopic anterior and low anterior resections.

16:38

Now, the goals of this procedure are to,

16:40

A, achieve adequate oncological resection.

16:44

B, create a tension-free anastomosis

16:47

with a good blood supply, and C, perform

16:50

a pouch reconstruction if necessary.

16:52

So.

16:53

The surgeons will use this technique to

16:55

actually give them a little bit more slack when

16:57

they're trying to create an anastomosis.

17:00

Um, so you can see what happens here in the

17:02

laparoscopic surgery is, um, the splenic

17:05

flexure is actually dissected, and then the,

17:08

um, colon itself is mobilized more inferiorly.

17:13

So that's what happened in this case.

17:15

Um, and unfortunately there was a hematoma

17:17

that developed during that procedure.

17:20

So the teaching points here are that not every

17:23

mass in a cancer patient is a metastasis, although

17:26

it's the first thing we normally think about and

17:28

we should think about it because it's common.

17:30

But just keep in mind that, um, there are

17:32

other differentials to consider, and we do

17:35

need to be aware of this surgical approach.

17:38

Now, we're not surgeons, so we're not gonna know

17:41

every approach and every technique that occurs,

17:44

but this is something that you would really only

17:46

learn in that multidisciplinary cancer care setting.

17:49

So now that we know that we

17:51

will be on the lookout for it.

17:56

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

17:58

Case four.

18:00

This is a 71-year-old male.

18:03

He, he presented with abdominal

18:05

discomfort, dysuria, increasing bowel

18:08

movements, and a significant weight loss.

18:10

So lots of different concerning symptoms.

18:13

His dysuria resolved with a course of

18:16

antibiotics, but he still had abnormal

18:18

stools, which was quite worrisome.

18:21

So he underwent colonoscopy and there was a

18:23

large rectal mass that was seen extending from

18:26

two to 12 centimeters from the anal verge.

18:29

Um, now the, the biopsy was performed,

18:33

but surprisingly the, um, histology

18:36

came back as focal reactive hyperplasia.

18:39

So an MRI was requested to assess the discordance

18:42

between the pathology and the colonoscopy findings.

18:45

So colonoscopy shows a large mass,

18:47

biopsy just shows reactive hyperplasia.

18:51

So let's look at the MRI.

18:52

So I've given you three select images, axial

18:56

T2, and then two post-gadolinium images.

18:59

And I'd like you to just take a look

19:00

at those and then answer the question.

19:02

So maybe we can just put the poll up now.

19:05

So what do you think the most

19:07

likely diagnosis is in this case?

19:09

So there's four different options here, so

19:12

I'll give you a minute or so to look at that.

19:18

Okay, so let's see what people thought.

19:21

Yeah.

19:21

So again, um, a spread of responses here.

19:24

Um, this is a really unusual and challenging case.

19:29

So, um, about half of people thought there was diffuse

19:32

lymphoma involvement of the bladder and rectum.

19:35

Um, there were others that thought this

19:37

primary rectal cancer with bladder involvement.

19:40

So basically all the choices were, um, possibilities

19:43

and, um, I don't blame you for having that

19:46

spread because it is a really challenging case.

19:49

So let's talk about it a little bit more.

19:53

Um, I'm gonna just ask you to

19:56

answer a couple more questions.

19:58

Um, so based on what you think

19:59

this is, what additional test would

20:02

be the least useful in this case?

20:04

So I'm being a little bit evil here, um,

20:07

using a, a negative stem, but which test do

20:11

you think would not really help in this case?

20:18

Okay, so most people thought

20:20

urinalysis would really not help.

20:22

Um, that's probably true.

20:24

Um, some people said cystoscopy, you might be able

20:28

to get a repeat biopsy if you did a cystoscopy.

20:31

Um, repeat endoscopy, 28% said

20:35

that would be the least useful.

20:37

Um, I would say that repeat endoscopy might

20:41

actually be helpful because the first biopsy just

20:43

showed reactive change, so you might be able to

20:46

convince the endoscopist to try to take a deeper

20:49

biopsy, so to get a little bit more tissue.

20:52

So, um.

20:54

Endoscopy actually could be helpful.

20:56

So could cystoscopy. Urinalysis,

20:58

I think is probably on the edge.

21:00

But remember, PET-CT.

21:02

Um, the primary, the primary

21:04

abnormality here is in the bladder.

21:06

And remember with FDG-PET, it's

21:08

excreted by the kidneys and the bladder.

21:10

So you'll have, um, a significant amount of

21:13

activity in the bladder, which will obscure

21:16

the nodularity of the, uh, the liver or the,

21:19

uh, bladder wall that we're seeing here.

21:20

So probably PET-CT would really not

21:22

help in this case because you really

21:24

wouldn't be able to see the abnormality.

21:26

So the answer for that question was C.

21:30

Okay.

21:30

So the patient did undergo further investigations.

21:33

There was a repeat urinalysis that

21:35

showed cells suspicious for malignancy.

21:39

The cystoscopy showed inflamed, engorged mucosa.

21:44

Repeat colonoscopy and mucosal biopsy again,

21:47

unfortunately was inconclusive and ultimately

21:51

the patient underwent a pelvic exenteration,

21:54

um, because there was such a significant

21:56

abnormality in both the bladder and the rectum.

21:59

So the pathology showed a high-grade urothelial

22:02

carcinoma with focal papillary pattern.

22:06

That was extensively invading all layers of

22:08

the bladder wall and the perivesical fat.

22:11

There was extensive invasion of the

22:13

rectum, um, and this was actually termed a

22:16

linitis plastica with sparing of the mucosa.

22:19

There was widespread lymphovascular and

22:22

perineural invasion, as well as prostate

22:25

invasion, and all of the lymph nodes in

22:27

the specimen were positive for malignancy.

22:29

So this is a very interesting and rare

22:31

case of linitis plastica of the rectum.

22:34

Now we've probably all heard about

22:36

linitis plastica in the stomach.

22:38

Um, and most commonly we learn breast cancer

22:41

metastases can cause that pattern in the stomach.

22:44

Um.

22:45

But it can also happen in other parts of the GI tract.

22:49

So what happens, um, in this particular

22:51

process is that there is infiltration of the

22:54

submucosa and the muscularis propria layers

22:57

of a hollow organ with cancer cells, and that

23:00

results in very significant wall thickening.

23:03

So just, let's just go back to our images here,

23:06

and you can see how the rectal wall is pretty

23:09

symmetrically and circumferentially thickened.

23:12

And if you look at the bladder, there's

23:14

only part of the bladder that's involved.

23:16

So, um, if this was in reverse, coming from the

23:20

rectum to the bladder, we would expect that,

23:22

um, most of the bladder wall would be affected

23:25

if it was hematogenous or lymphatic spread.

23:27

But in fact, it's only a portion of the bladder.

23:30

So that's a clue that the process is originating

23:33

from the bladder rather than the rectum.

23:35

But look at how thickened, um, the bladder — the rectal

23:39

wall rather — is, and how symmetric that thickening is.

23:43

So it does, the imaging findings really

23:45

do reflect the pathology in this case.

23:48

Um, and because the, um, deeper layers

23:51

of the rectal wall are affected by that

23:53

cellular infiltration, the organ becomes

23:56

very constricted, very rigid, and inelastic.

23:59

And that leads to this luminal narrowing.

24:01

So you can imagine if you were the endoscopist,

24:03

you would put your scope in, you'd see a

24:06

relatively normal mucosa because the mucosa

24:09

is spared, but the lumen would be very

24:12

inextensible and probably quite narrowed.

24:15

So the primary sites of this process

24:18

are often GU, stomach, or breast.

24:21

Um, usually unfortunately the disease

24:23

is quite advanced at initial diagnosis.

24:25

Um, if we can provide an earlier diagnosis,

24:27

that, that potentially can improve survival.

24:30

And one important point to keep in mind is

24:33

that the endoscopy is often a false negative.

24:36

So, um, that is really important to be aware of.

24:40

So even though, um, as radiologists we do rely

24:43

on the pathology to help us guide management,

24:45

remember that sometimes the pathology can be

24:47

wrong and it isn't always the gold standard.

24:49

It really needs to correlate

24:51

with the diagnostic imaging.

24:53

So, um, the rectum is contracted, non-

24:56

extensible, but the mucosa may look normal.

24:58

So if we get a superficial biopsy, we may get a false

25:02

negative that, you know, there's nothing going on.

25:04

A deep biopsy may be quite difficult

25:07

because of that non-distensibility.

25:09

Um, so we do need to.

25:11

Um, have a conversation with our

25:13

colleagues in the round setting to

25:15

discuss management of a case like this.

25:18

Um, and in this particular setting, MRI does

25:20

have a higher accuracy for diagnosis than

25:22

endoscopy does because we can see the tissues

25:25

around the rectum and the deep layers as well.

25:27

So what we're looking for on MRI is a concentric

25:30

mural ring or target pattern on T2-weighted images.

25:34

And, um, we may actually see the

25:37

source, um, um, of the, of the other

25:40

organs that are in the field of view.

25:42

So here are some gross and, um,

25:45

microscopic pathology images.

25:48

Uh, just giving us a, a picture of what,

25:51

uh, linitis plastica of the rectum looks like.

25:54

So this is a macroscopic view of the surgical specimen

25:57

showing the submucosal space is quite expanded.

26:00

The mucosa you can see is actually very smooth and

26:03

preserved, but the involved area is very, very thick.

26:06

So if you think about adenocarcinoma,

26:08

normally the mucosa is a little bit shaggy.

26:12

Um, there might be superficial

26:13

ulceration that we often see on MRI,

26:15

but in this case there's none of that.

26:17

Um, but there's a lot of fibrosis and

26:19

submucosal change in the involved lumen here.

26:23

Um, on the biopsy specimen at microscopy, there

26:27

is significant, uh, change in the submucosa.

26:31

Um, so these white arrows are

26:32

pointing to fibromyxoid change.

26:34

So a little bit of that fibrous, um, reactive change.

26:38

And then all of the malignant

26:39

cells are in the submucosa.

26:40

And you can see here the mucosa itself is normal.

26:43

So, um, it is a very, um, deceptive disease both

26:48

for the endoscopist and for the pathologist.

26:50

But as radiologists, we have, um, a, a deeper

26:54

look than either of those specialties might have.

26:56

So this was a very interesting

26:58

case that I saw at Tumor Board.

27:01

Now as a companion case, and this actually came

27:04

across my desk within three weeks of the last one.

27:07

This is a 76-year-old female who presented with

27:10

rectal bleeding, um, on digital rectal exam.

27:13

The description was a firm, hard mass at two to three

27:17

o'clock that was ulcerated with friable mucosa.

27:22

At anoscopy, there was an indurated mucosa,

27:25

friable mucosa affecting the entire rectum,

27:28

and that was concerning for malignancy.

27:31

Advanced malignancy was suspected.

27:32

An endoscopic biopsy was done, but the

27:35

report was pending at the time of the MRI.

27:38

So I want you to keep in mind, um, these

27:40

statements: firm, hard mass at two to three o'clock.

27:43

Ulcerated.

27:44

Friable, and.

27:46

Um, that abnormality affects the entire

27:48

rectum and is concerning for malignancy.

27:51

And I just put up a picture of the form that we use.

27:55

Um, we have asked all of our referring

27:57

physicians to fill out this form for all

28:00

rectal cancer cases because it really gives

28:02

us a better idea of where the abnormality is.

28:05

And for planning of the MRI, um, we've

28:08

all become quite reliant on this form.

28:09

So the surgeon will mark down where they

28:12

think the tumor is based on endoscopy, and

28:15

we've asked them to confirm these questions.

28:17

Has rectal carcinoma been confirmed?

28:19

And they say yes here, even though the

28:21

report was pending at the time of the MRI.

28:23

And then we have, um, we have them write

28:25

down a distance from the anal verge so

28:28

that it helps us when we're planning.

28:29

Um, we also ask whether the patient has had any

28:32

previous therapy at all and what the histology was.

28:37

So here, um, are some select

28:39

MRI images from this case.

28:41

So again, you can see most of the rectum is very

28:44

thick-walled, just like we saw in that last case.

28:46

The bladder here looks okay, but there's

28:49

kind of shaggy margins of the rectum.

28:51

Um, there is some enhancement as well.

28:55

And then, um, I wanted to point out

28:59

this kind of tram-track pattern.

29:01

So if I take those lines off again, you can see

29:04

that, um, there's a muscularis propria here, but then

29:07

there's also kind of a shaggy margin of the serosa,

29:10

and you can see that both anteriorly and posteriorly,

29:14

and it's a significant length that's involved.

29:16

And then there's also a little ulcer here.

29:18

So the endoscopist also

29:19

described an area of ulceration.

29:25

Again on the axial image,

29:27

um, a little bit hard to see here, but you

29:28

do kind of see that concentric ring pattern.

29:31

So what is this?

29:33

Is this another case of linitis plastica?

29:35

So I was hoping that the answer would be no,

29:37

after that last case that I saw at rounds.

29:40

And this turned out to be actually, actually chronic

29:42

active proctitis that was mimicking rectal cancer.

29:46

So this kind of fooled us a little bit,

29:48

because the information we were provided

29:50

was that of a malignancy confirmed, but

29:53

it actually wasn't confirmed on pathology.

29:56

Um, so on MRI, we can see very similar

29:58

findings to that linitis plastica case.

30:01

But the key features telling us that this is

30:03

not a typical adenocarcinoma are: one, there is

30:07

diffuse circumferential involvement of the rectum.

30:10

And typically adenocarcinoma

30:12

involves, um, uh, one focal area.

30:15

It's either the upper, middle, or lower rectum.

30:18

It's very unusual to get that

30:19

diffuse of an abnormality.

30:22

Again, there was uniform thickening of the

30:24

submucosa with some edema, so the differential

30:28

here would be a little bit broader.

30:29

So we would think about more infectious, inflammatory,

30:33

ischemic pathologies, and maybe an atypical

30:36

malignancy like we saw with the last patient.

30:39

But in this particular case, because the

30:41

morphology and distribution are atypical, we

30:44

do have to broaden our horizons a little bit.

30:47

So teaching points here are, um, as radiologists, we

30:51

do have a significant role to play in, um, actually

30:57

coming up with a treatment plan for the patient.

30:59

So, um, that's what I, I believe that the

31:02

forum of multidisciplinary conferences gives

31:05

us that platform because we're actually there

31:07

in person and we're discussing cases in person.

31:10

So remember that we are also clinicians, we're

31:13

part of the multidisciplinary team, so we really

31:15

shouldn't hesitate to question clinical or pathologic

31:18

findings if there is discordance with the imaging.

31:21

And if it just doesn't make sense, we should

31:23

mention that because we're really the only people

31:26

that may actually have that, um, information.

31:30

The other point is we really should be involved in

31:34

looking up pathology and endoscopy reports, or call,

31:37

even calling the pathologist to discuss findings.

31:39

Um, if we rely on information that's

31:42

given to us secondhand, like in this case,

31:44

um, it really could, um, be detrimental

31:47

for the patient and for our conclusion.

31:49

So we wanna be as accurate as we possibly can, but

31:52

in order to do that, we have to be a little bit,

31:54

we have to take a bit more initiative sometimes.

31:59

Okay, so let's move on to another case here.

32:02

Um, this is a 62-year-old female.

32:05

She actually presented to our department 16

32:08

years after resection of adenocarcinoma of

32:11

the rectum, and her complaint was a sensation

32:14

of swelling in the abdomen and pelvis.

32:17

She also had a history of bilateral

32:19

oophorectomy for benign disease.

32:21

So 62 years old, um, 16 years

32:25

after resection, swelling.

32:27

So, um, where do you think the abnormality is located?

32:30

So we can put the poll up now.

32:35

So just take a look at these two CT images

32:37

and choose where you think the abnormality is.

32:44

Okay.

32:44

So let's see what everyone thought.

32:46

So most people thought that the

32:48

abnormality was along the pelvic sidewall.

32:50

We had a few people vote for

32:52

adnexa, mesorectal fascia, and tumor.

32:56

So the answer in this case was

32:58

indeed the pelvic sidewall.

33:01

So, um, and I'll just point out the abnormality here.

33:04

So we've got a low-density mass with some

33:06

unusual calcification in it, and it's

33:09

contacting the right obturator internus muscle.

33:11

So there is involvement of the pelvic sidewall.

33:14

Um, it's kind of an extraperitoneal

33:18

mass, uh, with contact of the sidewall.

33:25

Now next steps.

33:26

What additional information, and again,

33:28

this is one of those tricky questions.

33:30

What additional information would

33:32

be the least useful in this case?

33:34

So out of all of these choices, if you had to pick

33:37

one that you wouldn't take, which one would it be?

33:43

All right, so we'll give you a few more seconds here.

33:46

And let's see.

33:47

So most of you said, okay, age at

33:49

menopause is probably not gonna affect

33:52

my conclusion, and you're correct.

33:54

So this patient also had bilateral oophorectomy for

33:57

benign disease, which was, um, part of the history.

33:59

So really the age at menopause is not going

34:02

to affect our differential diagnosis. Surgical

34:05

history, tumor markers, pathology, endoscopic

34:08

findings, those may all play a role

34:10

in, um, helping us arrive at our diagnosis.

34:14

So well done.

34:16

Okay, so we've got the MRI images here.

34:19

So remember that that, um, lesion on CT had

34:22

some calcification within it, which is showing

34:25

up as, um, low T2 signal, um, on the MRI.

34:29

So, uh, take a look at these images

34:32

here and then we'll just put up the

34:36

poll talking about the MR diagnosis.

34:41

And the question is, what additional

34:43

information would be most useful in this case?

34:47

So take a look at those images.

34:48

We've got a combination of T2 inversion

34:51

recovery, T1 with fat sat plus contrast.

34:55

Um, so you have quite a bit of information

34:57

to sort through on those images.

35:00

Um, but what else might you want to know?

35:07

All right, so why don't we put up the poll

35:09

now in the interest of time, because I wanna

35:11

try and get through the rest of the cases.

35:13

Okay.

35:13

So the vast majority of people thought

35:15

that the pathology of the original lesion

35:18

would be very useful in this case, and

35:20

it does have very unusual MRI findings.

35:22

So I would agree knowing that histology would help

35:25

us, um, try to figure out what the heck is going on.

35:29

So just to go over the MR findings, that mass

35:32

you can see kind of has irregular borders.

35:34

It's predominantly high signal on

35:36

T2, which is really interesting.

35:38

Um, and you can see that there is some

35:41

abutment and probably superficial invasion

35:43

of the right obturator internus muscle.

35:45

And we've got some calcification as we

35:47

saw on CT, and there's rim enhancement,

35:49

so very little solid enhancement.

35:51

It's predominantly a low, um,

35:53

density and high signal mass.

35:55

So probably some sort of fluid

35:56

that's in there, or, um, potentially.

35:59

Um, some other, uh, matrix from the tumor.

36:05

Okay, so this actually turned out to be mucinous

36:08

adenocarcinoma of GI origin on biopsy, and it

36:12

was thought that this was a delayed metastasis.

36:15

So 16 years out, this patient presented, um,

36:19

with a metastasis along the pelvic sidewall, and

36:22

the pathology did fit her original, um, lesion.

36:27

So in 1998, she had a mucinous adenocarcinoma

36:30

arising within a villous adenoma, and then had

36:33

a low anterior resection with negative margins.

36:36

Um, unfortunately she had a pretty complex

36:38

course with a lung metastasis in the left

36:41

lower lobe, then followed by chemotherapy.

36:43

And then until 2015 she was relatively disease free.

36:47

And that's when she presented

36:48

with this pelvic sidewall mass.

36:50

Her serum CEA level went up to 50.

36:54

So again, the tumor markers

36:56

were quite useful in this case.

36:58

And then the biopsy showed a mucinous lesion,

37:00

which explains the signal characteristics on MRI.

37:03

So here the learning point is that knowing the

37:05

original histology, the patient's cancer history,

37:08

and the relevant tumor markers can be very,

37:10

very useful in making an accurate diagnosis.

37:13

So although sometimes we need to actually get that

37:15

information ourselves and we need to pull it from

37:18

different sources, um, it really gives you a lot

37:20

more confidence in making a, an accurate diagnosis.

37:25

Great.

37:25

Okay, so let's move on to case number six.

37:28

So this is a 77-year-old female who has

37:31

squamous cell carcinoma of the left anal canal.

37:34

And she came to us for CT

37:36

and MRI staging of her tumor.

37:38

So I'm gonna just point out the tumor here for

37:41

you on the MRI, but there's, um, another finding

37:44

here that I wanted you guys to take a look at.

37:47

So let's put the poll up.

37:51

And the question is, which member of the MCC team

37:56

would find the incidental finding most relevant?

37:59

So first you have to find the incidental finding

38:00

here and then figure out which member of the

38:05

multidisciplinary team would find that most relevant.

38:11

Okay.

38:12

So maybe give you a few more seconds and great.

38:16

So most of you said radiation oncologist, so good job.

38:19

And the incidental finding here is, um,

38:23

avascular necrosis here of the left femoral head.

38:27

And you can see that just at the top of

38:30

the T2-weighted images here of the head.

38:34

And I find that sometimes we can miss these

38:37

on MRI of the pelvis, but in a patient

38:40

who's had chemoradiation, um, I always try

38:43

and make this part of my search pattern.

38:45

Um, especially on the MRI, sometimes the CT, um, may

38:49

not be available or they may not have had it yet.

38:51

So we really need to make this

38:53

part of our approach on the MRI.

38:58

So, um, the incidental musculoskeletal findings

39:02

can be actually quite relevant for treatment

39:04

planning in lots of different malignancies.

39:06

You can see here that, um, they're

39:09

planning their target volume for radiation therapy.

39:11

And so if we know, and if we provide the information

39:14

of, um, avascular necrosis here in this case,

39:17

they'll definitely do their best to avoid that

39:19

area when, when administering radiation therapy.

39:23

So, good job on that case.

39:27

Okay, so the next case is a 58-year-old male.

39:30

He presents to us status post distal

39:33

pancreatectomy, splenectomy, and right

39:36

hepatectomy for adenocarcinoma or pancreatic cancer.

39:39

So he's been through the ringer.

39:41

Um, and he came to us for his first follow

39:44

up imaging after neoadjuvant, uh, chemo-

39:47

radiation, sorry, chemotherapy and surgery.

39:49

So, um, splenectomy, distal pancreatectomy, right

39:53

hepatectomy, and now presenting for follow up.

39:55

And he is only 58.

39:57

Um, so I'm gonna show you, uh, liver

39:59

windows for this patient in both the

40:02

arterial and the portal venous phase here,

40:07

and the abnormality is a little bit

40:09

tricky, so I'll just circle it for you.

40:12

So there it is on the arterial phase

40:14

image, and let's put up the poll here.

40:20

What do you think the most appropriate

40:22

management will be for this finding?

40:29

So four choices there.

40:33

We'll give everyone a couple more seconds here.

40:39

All right, let's see what we thought.

40:41

So, um, about a quarter of us wanted to follow, um, some

40:46

same quarter of us said no specific recommendation.

40:49

Um, there was a minority of people who

40:52

wanted to correlate with tumor markers,

40:54

which I don't think is unreasonable.

40:55

And then the majority of the group

40:57

wanted to do an MRI, which I think

40:59

would probably be the next best step.

41:01

You could certainly correlate

41:03

with tumor markers as well.

41:04

Um, follow up with CT in three months.

41:08

Um.

41:09

You could do.

41:10

But remember, over that three-month period of time,

41:13

we don't really have anybody monitoring anything.

41:15

And actually that's what was

41:17

suggested for this particular case.

41:19

But I will show you what happened, and that's

41:22

part of the reason that I think doing an

41:24

MRI is probably what we should be doing.

41:29

Okay, so the patient actually

41:30

came back, um, four months later.

41:33

So it was a little longer than that three months.

41:36

And, um, there were some alarm bells that went

41:39

off at the referring physician's, uh, office

41:41

because of elevated liver function tests.

41:43

So we did an ultrasound, and you can see that

41:46

this mass has grown in size in segment two.

41:49

So there's, um, a subcapsular

41:52

segment two hypoechoic mass.

41:54

Um, we can see it quite superficially.

41:56

And, um, interestingly, which is why this case

41:59

is in the talk, the tumor markers were normal.

42:01

So we can't rely solely on tumor markers.

42:04

I think if you're going to say follow up

42:06

with tumor markers, you should do that

42:08

in conjunction with an imaging test.

42:10

So that's why, um, tumor markers is not

42:13

the best answer for that last question.

42:16

Okay.

42:17

So, um, unfortunately this patient sort

42:20

of got lost to follow up, so you can see

42:23

what happened over time between February.

42:26

In June, uh, the patient came back

42:28

for the CT after that ultrasound, and

42:31

you can see that lesion has now grown.

42:33

So just going back to the original set of images,

42:36

I just wanted to show you that, um, in the arterial

42:38

phase, we actually do see some enhancement,

42:42

but where is it on the portal venous phase?

42:44

It's very hard to tell.

42:45

So we might be tempted to call this a FAD,

42:48

a transient hepatic attenuation difference.

42:51

Um, and I, I think that would

42:53

be perfectly reasonable to say.

42:55

Um, differential diagnosis would probably

42:57

be a small metastasis, but definitely you'd

42:59

want to recommend an MRI and maybe some tumor

43:02

markers just considering the patient's history.

43:04

And so the mass grows, um, on CT and ultrasound.

43:10

So, um, FADs or THIDs can be the

43:13

earliest sign of a metastasis.

43:15

So remember there's two different

43:16

types of, um, transient hepatic

43:19

attenuation or intensity differences.

43:21

The first type is just due to, um, alteration

43:24

in, um, arterial and portal

43:26

venous supply to the liver.

43:28

Um, and sometimes that alteration can occur

43:31

because of a lesion, and that's the second type.

43:33

So remember that the liver is primarily supplied

43:36

by the portal system, but if there is, um, a

43:39

solid lesion that deposits in the liver, it's

43:42

going to recruit more arterial supply,

43:45

which is why you get that enhancement in the

43:47

arterial phase rather than the portal venous phase.

43:50

So keep in mind that THIDs and THADs in cancer

43:53

patients can be a sign of a metastasis.

43:55

Be aware of that arterial phase.

43:57

Imaging and diffusion-weighted imaging can be

43:59

quite sensitive for detection of small mets.

44:02

So we should use those tools

44:04

that we have at our disposal.

44:06

And when lesions are small,

44:07

serum biomarkers may be normal.

44:09

So don't rely only on tumor markers

44:12

when following these patients up.

44:14

So, um, as radiologists, we're always looking

44:17

for disease, so continue to hunt carefully,

44:20

um, that may actually allow the patients to

44:22

undergo more localized therapies like, uh,

44:25

radiofrequency ablation or focal resection.

44:30

Okay, so we've got a couple more cases here and about

44:32

10 minutes left, so maybe I'll try to go through

44:34

at least one so we can, um, answer some questions.

44:38

The next case is a 73-year-old male.

44:41

He was diagnosed 18 months earlier with right

44:44

colon adenocarcinoma, treated with a right

44:47

hemicolectomy and had N0 M0 disease,

44:51

no adjuvant therapy or neoadjuvant therapy.

44:55

And he is now presenting with abdominal pain.

44:56

So, um, 18 months ago, right colon cancer treated

45:00

only with surgery and now he comes to us, um, with.

45:06

This set of images, so August 2016, and

45:09

we did have an earlier set of images,

45:11

um, that were unrelated to his cancer.

45:13

So I want you to, um, just take a

45:15

look at these two important findings.

45:21

And I'll just add to that a little bit.

45:23

So I'm just giving you some narrower windows to

45:29

help with that.

45:32

So hopefully you've seen the two abnormalities here,

45:38

and then the patient underwent a PET-CT and I've just

45:42

given you the CT images with the liver windows to

45:45

compare, just so you get a sense of what's going on.

45:49

So let's put the poll up now.

45:53

Um, so the patient has a right adrenal mass.

45:58

And a liver mass.

45:59

And the liver mass you can see is quite hot.

46:02

And FDG avid.

46:03

So regarding the right adrenal mass,

46:06

um, it's most likely to demonstrate

46:08

which of the following features on MRI.

46:12

So will it be avid homogeneous enhancement,

46:14

diffuse signal drop on out-of-phase

46:16

images, hemorrhagic content, or non-uniform

46:20

signal drop on out-of-phase images.

46:23

And just for reference, I'm going to

46:24

just go back here just to show you again.

46:28

So this is, um, October 2011, August 2016.

46:32

So the right adrenal mass is there in October 2011.

46:37

But what do you think the signal

46:39

characteristics are gonna show?

46:43

Okay, so the majority of people thought that we would

46:46

see non-uniform signal drop on out-of-phase images.

46:49

So very well done.

46:51

So you guys obviously picked up that, um, there was

46:54

an adrenal adenoma here, um, from five years earlier.

46:58

So you can see the low density.

46:59

Now, the difference between, um, 2011 and

47:03

2016 is the development of this small soft

47:06

tissue mass, which has occurred over time.

47:08

And obviously there's new metastasis,

47:10

um, centrally in the liver.

47:12

And you can see also in the PET that

47:14

there's some uptake in that, um, more

47:17

solid-looking part of the adrenal lesion.

47:20

So this turned out to be an adrenal collision tumor,

47:23

uh, which is the coexistence of two adjacent, but

47:26

histologically distinct tumors of the adrenal gland.

47:28

And it can be any combination

47:30

of benign and/or malignant.

47:32

So it doesn't have to be a malignancy or

47:33

a met, it can be two benign lesions or

47:36

a combination of benign and malignant.

47:38

Um, now this would really be, um, something that

47:42

would come to your mind if you notice a change in

47:44

attenuation or increase in size of a preexisting mass.

47:48

At CT.

47:49

At MRI, we're looking for non-uniform signal

47:52

drop on out-of-phase images as you see here.

47:55

So there's a little nodule here that

47:57

does not have, um, uniform signal drop.

47:59

We might see variable T2 signal

48:01

and enhancement, and then on PET.

48:04

Um, you may see FDG uptake greater than the background

48:08

normal liver, and that is suspicious for a met.

48:10

So if we go back to our PET, you can see the

48:12

normal background liver, um, does not really

48:15

take up a significant proportion of FDG, but

48:17

that little nodule, and it's quite small in

48:19

size, does have increased, um, FDG uptake.

48:23

So that is suspicious.

48:25

So this was a patient with, uh, collision

48:27

tumor, uh, metastasis from colon cancer.

48:32

Okay.

48:33

And I think I only have one more case.

48:35

So why don't we try and finish that.

48:37

Uh, this is a 53-year-old female with a

48:40

low rectal mass that presented for staging.

48:43

So we've got, um, several T2-weighted images

48:45

and I've given you diffusion and ADC as well.

48:50

So let's put the poll up here.

48:56

So take a look at these images, um,

48:59

figure out what you think is going on.

49:01

Um.

49:02

In particular, um, regarding the staging of

49:06

the rectal mass, um, the T staging, it may be

49:10

difficult, but if you can kind of come up with

49:12

an idea in your head of how advanced this disease

49:15

is, what additional information do you think would

49:17

be most useful to predict her overall prognosis?

49:25

So we've got CEA level, involvement of

49:27

the pelvic floor, history of irradiation,

49:30

or histology of the primary tumor.

49:37

All right, so let's see what everybody thought.

49:39

So, most of you thought the histology of the tumor

49:42

would be most useful, and I would agree with you.

49:44

So well done.

49:45

So, um, let's just go over the images quickly.

49:48

So we've got a low rectal mass here.

49:50

Um, it's semicircumferential,

49:52

predominantly on the left side.

49:54

Um, it looks like it probably contacts the sphincter,

49:56

but difficult to tell without the coronal images.

49:59

There is most likely a little bit of

50:01

extension deep to the muscularis here.

50:04

Um, but the most important finding I wanted

50:06

you to, um, try to identify were these things.

50:11

So this, this, this.

50:14

And then on DWI, you can see

50:16

that there's T2 shine through.

50:20

So these are actually mucinous lymph nodes.

50:22

And you may or may not have seen this before

50:25

in your practice, but, um, this is a pitfall

50:28

of rectal MRI because usually, um, our

50:32

sequences are not done with T2 fat sat.

50:34

Because of this problem, I tend to include

50:37

inversion recovery or T2 fat sat images

50:39

on all my rectal cases because I don't

50:41

really wanna miss these mucinous lymph nodes.

50:44

And if you don't know that the patient has mucinous

50:46

histology, you could easily just scroll through these

50:49

and not really recognize that they are abnormal.

50:52

You might just think there's a fatty hilum,

50:54

but remember to think about the shape

50:56

of the node: spherical versus elliptical.

50:59

The spherical nodes tend to be abnormal and

51:02

this much high T2 signal centrally within

51:05

a node is not typical for rectal cancer.

51:07

So if you see this, this appearance, try to, um.

51:11

Make it part of your search pattern.

51:12

And remember that mucinous lymph

51:14

nodes can, uh, look like this.

51:16

And then the DWI and ADC, if you don't

51:19

have the T2 fat sat images or the IR

51:22

images, you'll see T2 shine through.

51:24

And that's a giveaway that this

51:25

is mucinous lymphadenopathy.

51:30

So, um, in mucinous rectal cancer, the

51:32

lesion contains pools of extracellular mucin.

51:35

And one of the theories about why the prognosis

51:38

is worse is that these pools of mucin increase the

51:41

overall pressure in the tumor, and that may kind of

51:44

allow seepage of cells into the peritoneal cavity.

51:47

Whether or not this is true, it's hard to know.

51:49

It's just a theory.

51:50

Um, but it kind of helps you

51:52

with that thought process.

51:53

And unfortunately, these patients do have

51:55

a poorer survival compared to non-mucinous.

51:58

The tumors are also not very cellular,

52:00

so the response to chemotherapy is also

52:03

poor compared to very cellular tumors.

52:06

And having mucinous disease alone may be

52:09

an independent poor prognostic factor.

52:12

So at MRI,

52:13

look carefully for the node signal.

52:15

So don't just look for the nodes, but

52:17

look for the node signal and use those

52:19

tricks to help the nodes stand out.

52:21

Um, on ADC and DWI, if you see

52:25

persistent high T2 signal, that's not fat.

52:28

So do be aware of that, um, in, um, mucinous disease.

52:33

And again, sometimes you don't know that it's

52:34

mucinous, and that's another reason to look up the

52:36

endoscopy report, the pathology report, et cetera.

52:40

All right, so that's all I had for cases.

52:42

So thank you so much for your

52:44

participation and for being here today.

52:46

And I think we have a little bit

52:47

of time to answer a few questions.

52:49

Yeah, that would be great.

52:50

I see at least one question in the Q and A

52:51

right now, if you don't mind answering that one.

52:53

Mm-hmm.

52:55

I'll just open that up here.

52:57

Okay.

52:57

So how do we measure the meso

52:59

rectal extension exactly?

53:01

Is it from the outer margin or the inner margin?

53:04

Okay.

53:04

So I think what I'll do is I will

53:09

go back to one of our slides that

53:12

had a nice tumor to look at, a

53:15

little bit easier to describe.

53:18

Um,

53:21

and then I'll hopefully be able to draw on that

53:24

so I can actually describe what I do for that.

53:28

Okay, so let's use this image here.

53:31

So, um, what I try and do is I look for

53:35

the muscularis propria first, because

53:38

that's usually easiest to identify.

53:40

So luckily the muscularis propria itself is a dark

53:44

line, and the tumor usually is intermediate signal.

53:48

So you can see in this case,

53:50

um, I just blow this up here.

53:54

Hopefully you can see that the tumor itself has a

53:57

little bit higher signal than the muscularis propria.

54:00

So in this particular case, um, I can see

54:04

that the muscularis propria is right here.

54:07

And now this is the case that had that weird

54:09

little curve, so maybe we'll ignore that.

54:11

But there is certainly tumor here

54:14

and I can identify the muscularis.

54:15

So I'm looking for the integrity of that line.

54:19

I wanna make sure that line is intact.

54:21

And if it's not intact, I'll see

54:23

an interruption or a breakage.

54:25

So let's say there was some tumor that was

54:28

extending beyond here, I would, um, look for

54:31

the edge of that tumor, and then I would use my

54:35

measurement to go to the mesorectal fascia.

54:38

So I'm just supposing that the line of the mesorectal

54:41

fascia goes approximately down here.

54:43

It may actually taper a little

54:45

bit and may go like that.

54:46

So I would measure that from the edge of

54:50

that extension to the mesorectal fascia.

54:53

And that would be your distance

54:55

that you would measure.

55:00

Okay.

55:00

Um, DWI, would you recommend it as routine, or is

55:03

it more beneficial in post-managed rectal tumors?

55:07

Okay.

55:08

Um, so we do, we did actually have, um,

55:12

the Society of Abdominal Radiology, um, and

55:15

ESGAR work together to come up with specific

55:18

recommendations for rectal cancer imaging.

55:20

So they actually polled, um, several experts

55:24

at multiple different institutions across,

55:27

um, the world — actually Europe, North America.

55:30

Um, there were some contributors from Asia as well.

55:34

Um, and so they asked all

55:35

these experts about DWI, and um.

55:39

There was really no consensus that

55:40

was reached in terms of its value.

55:42

So it's sort of been left up to individuals to

55:46

decide whether or not they want to include it.

55:48

Personally, I think it's critical.

55:50

So I always use DWI, um, not

55:54

necessarily because it helps me.

55:56

Um, stage lesion, it just helps with detection.

55:59

So I just like having a safeguard.

56:01

Um, so if I can't find the tumor, for example,

56:04

on a sagittal T2-weighted image,

56:06

because it's small, I use the diffusion to try and

56:09

localize where the tumor is, and then I go back, I

56:11

triangulate back to the sag, and that really helps me.

56:15

So it's mainly for detection and localization.

56:18

Um, in post-, uh, in restaging rectal cancers, it

56:22

is also helpful, but again, the tumor is smaller,

56:26

so the accuracy of DWI in restaging, unfortunately,

56:30

is limited because the tumor has shrunk.

56:32

And the, um.

56:34

Resolution of the DWI is poor.

56:36

So mainly it's used for detection, but yes,

56:39

I would, I would recommend including it.

56:43

Okay.

56:43

And we have another question.

56:44

Any change in MRI imaging protocol in

56:46

post-chemoradiation rectal cancer case?

56:49

So that's a good question.

56:51

Um, and again, that consensus statement, um, we

56:56

have not recommended a change in the protocol.

56:59

Um, the routine protocol is

57:01

for three millimeter slice.

57:04

Um.

57:05

Images in all three planes,

57:07

coronal, sagittal, and axial.

57:09

Um, gadolinium is not necessary, but you can do it.

57:13

Um, endoluminal contrast.

57:15

And I know someone just asked about contrast.

57:17

So endoluminal contrast, um, is up to the institution.

57:21

Probably about 30 to 40% of institutions use it.

57:24

I don't use it.

57:25

I just find it's cumbersome, and it takes

57:27

up time, and it doesn't really add much,

57:29

um, to my staging, so we don't use it.

57:32

Gadolinium, um, can be used for primary and

57:36

secondary staging, but if you have a good 1.5 or

57:38

3T, don't necessarily need it. When it's useful,

57:42

I think,

57:42

most is when you've got T4 disease

57:45

and you're looking for extension outside

57:47

the rectum and into the, um, other pelvic

57:50

viscera like we had with the, uh, linitis

57:52

plastica case.

57:53

Um, so to answer those two questions, post-

57:57

chemoradiation, there's really no change.

57:59

Um, one thing I would like to add also is,

58:02

um, the utility of, um, antiperistaltic.

58:06

So, depending on which country you practice

58:08

in, you may have access to Buscopan or glucagon.

58:13

And, um, I find use — like, um, routine use of

58:18

antispasmodics or antiperistaltic is

58:22

extremely useful to limit motion artifact.

58:24

And I find if it's not used, you're much

58:27

more susceptible to, um, motion artifact.

58:30

Um, and that really affects your

58:32

T-staging of primary tumors.

58:34

So I would recommend definitely

58:35

using DWI and, um, antispasmodics.

58:41

Okay.

58:41

Um, Ellie, any relevance of

58:43

inguinal nodes in rectal cancer?

58:46

Um, not usually for adenocarcinoma of the rectum, but

58:49

anal cancer certainly can spread to inguinal nodes.

58:52

So, um, in our protocol, um, although we do try

58:56

and reduce our field of view for the rectum itself,

59:00

when we're looking at the rectal cancer, um, we

59:03

do also recommend a full field of view pelvis so

59:06

that we can see the groin, and we start at the, just

59:09

above the aortic bifurcation and go all the way

59:11

down to include the inguinal nodes for that reason.

59:14

Sometimes you don't know if the

59:15

patient has anal cancer or not.

59:17

It's a bit of a toss-up, but usually the

59:20

inguinal nodes would be more relevant in,

59:22

um, anal cancer rather than adenocarcinoma.

59:27

Okay, next question.

59:28

If we see mesorectal lymph nodes close

59:30

to the CRM, will we call CRM involved?

59:33

So, um, this is a really interesting question.

59:36

I actually just had a colleague ask me that yesterday.

59:39

Um.

59:40

Now, interestingly, literature that's been

59:43

recently published, um, in the last couple

59:45

of years has shown that the impact of a

59:48

positive node that's adjacent to the CRM is

59:52

the same as if the patient was node negative.

59:55

So what do I mean by that?

59:57

Well, um, CRM becoming positive is

60:00

really only affected if the tumor

60:03

is touching or threatening the CRM.

60:06

So if you've got tumor that's clear of the CRM, but

60:10

there's one lymph node that's close to the CRM, it

60:13

really doesn't threaten the integrity of the CRM.

60:16

If you look at the pathology now, do the

60:19

surgeons want to know that that node is there?

60:21

Absolutely.

60:22

So you should put it in your report that

60:24

there is a lymph node contacting the CRM

60:27

that looks abnormal and probably N-positive.

60:29

However, what will actually happen over

60:32

time is it's very unlikely that that

60:35

positive node will make the CRM positive.

60:39

So it's an interesting, very interesting

60:40

question and very relevant, I think, too.

60:42

So what I do is I call it CRM clear, but

60:45

then I put a little disclaimer there, and

60:48

I say, however, there is an abnormal node

60:50

contacting the CRM, just so the surgeon knows.

60:53

They have to be very careful to try and shell it out.

60:55

But the likelihood that the CRM

60:57

will be positive is extremely low.

61:01

Um, do you use MRI for peritoneal

61:03

cancer and for Peritoneal Cancer Index?

61:06

Um, my practice typically doesn't.

61:09

I know that there are others that

61:11

use it for peritoneal cancer.

61:13

Um, I don't see as much of that in my

61:15

practice as probably others would, but, um,

61:18

my limited experience with that, um, I know

61:21

that it can be quite useful, unfortunately.

61:24

I'm sorry I don't have enough experience in that area

61:26

to, um, provide you with a more expert response, but,

61:29

um, I know that I do have colleagues that use it.

61:34

Um, do inguinal lymph nodes affect

61:36

the staging of rectal cancer?

61:38

Yes.

61:39

So inguinal lymph nodes, um, are considered

61:42

distant metastases for rectal cancer.

61:45

And again, as I mentioned earlier, um, it is

61:47

unusual to get inguinal, um, node involvement.

61:51

Um, usually the spread

61:53

is more central and cranial.

61:56

So if you've got a rectal cancer, the nodal

61:59

spread tends to follow the venous spread.

62:01

So the venous, um, the venous drainage

62:04

does not go to the inguinal nodes.

62:06

It actually goes more cranial.

62:08

And that's how the lymph node

62:10

spread tends to be as well.

62:12

When you've got an anal cancer, the venous

62:14

drainage actually does go to the groin as

62:17

well, and so does the lymph node drainage.

62:19

So, um, I would recommend there are several

62:22

papers that go through the nodal spread of rectal

62:25

cancer, and that I think is very, very helpful.

62:28

Um, and I have a whole other talk on lymph nodes.

62:30

I wish we had time to go into that,

62:32

but maybe on another day we can talk

62:34

about the lymph node, um, staging.

62:36

'Cause that's a, a mystery for a lot of us.

62:40

So I think I've answered pretty

62:42

much all the questions there.

62:44

Um.

62:46

Ashley.

62:47

Yep.

62:47

Perfect.

62:47

So I wanted to thank you,

62:49

Dr. Kassam, for your time today.

62:50

We really appreciate it.

62:51

And thanks all of you for

62:52

participating in this Noon conference.

62:53

A reminder that it will be made available

62:55

on demand at mrionline.com in addition

62:58

to our previous Noon conferences.

62:59

And tomorrow we'll be joined by

63:00

Dr. Silvia Chang for a lecture on prostate

63:02

MRI. Thank you, and have a wonderful day.

63:05

Thank you.