0:00

Okay, so this is a 67 year old male with rectal cancer,

0:05

presenting for primary staging. I'm just going to scroll through that.

0:09

This is another kinda technical type case here. You can see that there's

0:15

a pretty obvious mid to low rectal tumor. It's circumferential. Again,

0:20

we've got these raised, rolled edges here. It's quite long. It's probably

0:26

about five to seven centimeters in longest length. You can see that

0:30

the sphincter mechanism is spared in this case. Just scrolling through that,

0:35

just talking about some protocoling and planning. Let's put up the first

0:42

question here. Which of these angles would you choose for your axial oblique

0:48

image? As you know, when planning the axial obliques, you really need to

0:54

take into account the angulation of the tumor and the position of the

0:59

rectum. This is very much a radiologist dependent feature. You need to dialogue

1:04

with your technologist on the fly when planning these cases. They're not

1:08

really plug and play like some of the other imaging that we do.

1:10

Please vote for which angle you think would be best for the axial oblique.

1:16

I'm just going to hide just for a second to give you

1:19

a look here and then there we go.

1:22

A, B, or C. The majority of people said B, and yes,

1:26

that is correct. The reason why that's correct is,

1:31

if I take off these annotations and you look very carefully,

1:34

you can see a little bit of signal that's extending deep to the

1:40

muscular is appropriate and the adjacent back, if you scroll through.

1:43

Otherwise, the muscular is actually looks pretty well maintained throughout.

1:48

That's one reason why B would probably be the best plane. If you

1:54

look at the angles of A and C, they're not exactly perpendicular to

1:58

the rectal lumen and to the tumor, which we would want to see

2:01

for the ideal axial oblique. And then C is actually almost out of

2:07

the tumor. You definitely wouldn't want to have something too high or too

2:13

low just in case you're missing a little bit of obliquity. That's the

2:16

reasoning behind answer for B. Let me just go show you a couple

2:23

of other sequences here. This is the axial oblique that actually was

2:32

a result of that planning. You can see there's quite a few lymph nodes

2:38

or tumor deposits in the adjacent fat. This little outpouching of tumor

2:45

extending into the adjacent fat is actually the area that we see here.

2:52

Having an appropriate axial oblique is really critical, because if you want

2:56

to measure the extramural depth of invasion as you would in this case,

3:00

you want to actually get the longest measurement possible.

3:04

Let me see if I can actually annotate on this.

3:07

There we go. As I was saying, the longest distance of the extramural depth

3:13

of invasion is the one that's most accurate when you're staging these cases.

3:18

Good job on that question. I think I'm going to just move on

3:24

so we have a little bit more time to discuss some pathology.