0:01

Okay, so let's talk a little

0:02

bit about MRI technique.

0:05

So pelvic imaging is really dependent

0:08

on good-quality T2-weighted images.

0:10

That's kind of the workhorse sequence

0:12

for pelvic MRI, and it just gives

0:14

us really good intrinsic contrast.

0:17

So the pelvic viscera themselves are very well

0:20

seen on T2-weighted images because the different

0:23

tissues do have characteristic T2 appearances.

0:27

So we really want to make sure

0:29

we've got very good quality and

0:31

good resolution T2-weighted images.

0:33

I usually like to make sure that I have at least

0:35

one sequence that includes the whole pelvis.

0:38

So at my institution, we do axial T2 and

0:41

inversion recovery of the whole pelvis.

0:43

And that we do just to make sure that we're

0:45

including all the various lymph node levels.

0:49

So if we're imaging a cancer patient, we

0:51

at least want to get to the IMA branch

0:54

so that we're including the lower para

0:57

aortic and common iliac lymph nodes.

0:59

I find the IR images very useful to

1:01

look for edema, and lymph nodes also

1:04

pop out at you on that sequence.

1:06

So both of those I find very useful.

1:08

Sagittal is usually where you start.

1:11

So you get sagittal images and then

1:12

plan the rest of the case that way.

1:14

You may want to image according to the

1:17

plane of the uterus or to the cervix.

1:19

And in that case, you'll get axial,

1:21

sagittal, and coronal oblique images.

1:23

And usually our field of view is small,

1:25

so it's about 200 to 220 millimeters.

1:28

Pre- and post-contrast T1-weighted images with

1:31

gadolinium are done with fat saturation, and

1:35

usually we do those when we're looking for

1:37

masses, or cancer staging, or vascular lesions.

1:40

Some institutions do them routinely.

1:43

We tend to be a bit more selective about when

1:45

we give gadolinium just because of some of

1:47

the inherent risks of GAD and to save on time.

1:51

DWI and ADC images are really

1:53

useful for oncology cases.

1:55

So I would encourage those become

1:57

a routine part of mass cases.

2:00

And then we really find it useful to administer

2:03

a spasmolytic agent prior to the study.

2:05

So here I actually have two

2:07

images from a rectal cancer case.

2:09

So on the bottom is the image that was done

2:13

without a spasmolytic, and you can see the

2:16

tumor here is very difficult to identify.

2:18

It's blurred, and on the top, this is

2:20

with the spasmolytic agent, and we can

2:23

see a tumor here much more clearly.

2:25

So I've gotten very used to using spasmolytics

2:29

and they really improve image quality.

2:31

So if you're able to use them at your

2:33

institution, I would highly recommend it.

2:36

So normal appearance of the ovaries and

2:38

adnexa is very important to know. If we

2:40

are comfortable with what's normal, it's

2:42

a lot easier to spot what's not normal.

2:45

So a normal ovary has a low to

2:48

intermediate T2 stroma and cortex, and

2:51

multiple high T2 signal follicles.

2:54

Because the ovaries tend to be a

2:56

little bit mobile in the pelvic cavity,

2:58

they can sometimes be hard to find.

3:00

So I tend to look for follicles,

3:02

especially in premenopausal women.

3:04

Once you find the follicles, that tells you

3:06

obviously where the ovary is. In postmenopausal

3:09

women, it can be a bit more challenging

3:11

because they have fewer follicles, but looking

3:13

for the follicles usually is quite helpful.

3:17

We don't normally see fallopian

3:19

tubes unless they're abnormal.

3:21

And in terms of characterizing ovarian

3:24

lesions, sometimes some lesions have

3:27

very characteristic appearances, like

3:29

teratomas, which we'll talk about. But

3:32

pinealoplasms have unique appearances on MRI.

3:35

So MRI usually isn't considered a first-line

3:38

modality, but it's more of a problem-solving

3:41

tool, and ultrasound tends to be first line.