0:00

Part three, we're going

0:01

to briefly talk about intravenous iodine contrast.

0:04

And we mentioned it briefly in the prior section

0:07

where we were talking about patients needing their renal

0:10

function checked and then having that injection.

0:12

So I didn't actually put in when the patient has the

0:14

injection on that prior because it is optional,

0:16

it's not available in every center,

0:17

but it's certainly something that we do in our practice

0:21

and we give intravenous contrast

0:23

because we know that the PSMA ligand is renally excreted.

0:26

And you can see here how hot the kidneys are

0:29

and then you can see the ureter and bladder there.

0:32

Tricky thing is with prostate cancer imaging,

0:34

we are looking very closely at the pelvis,

0:36

but we are also looking for the prostate itself

0:37

but also for pelvic lymph nodes.

0:40

Um, and so the more that we can encourage the tracer to move

0:43

through, through oral hydration,

0:44

which will come up in an upcoming section,

0:46

and then also give us some tools to be able to distinguish

0:48

what is physiological radio, urine

0:50

or excretion of the tracer and what may be disease.

0:55

And so that's the question when I go to interpret,

0:58

is this a spot of uptake I'm seeing in the pelvis?

1:00

Is that radio urine or is that disease?

1:03

And that is both for considering pelvic

1:05

and retroperitoneal lymph nodes

1:06

but also looking um, in the central prostate

1:09

for foci of uptake.

1:10

As we know, the urethra

1:11

goes straight through the middle of the prostate.

1:13

So in we use intravenous contrast for delineation

1:16

of the urinary tract, so kidneys, ureters, bladder,

1:19

particularly the pathway of the ureters

1:22

as they move through the pelvis.

1:23

Um, and then looking through

1:25

that central prostatic urethra as well.

1:28

We give um, the patients tracer 20 minutes

1:31

before they are due to be scanned.

1:33

So we're essentially getting a delayed IVP phase, um,

1:36

where we are only just wanting

1:38

to see intravenous contrast within the collecting system.

1:41

And that gives us a ification of the renal pelvis,

1:44

the ureters and the bladder

1:46

whenever we give intravenous iodine.

1:48

Contrast renal impairment is a consideration, um,

1:50

which is why we tend to screen um, a EGFRs

1:53

before injecting our patients

1:55

and we don't give IV contrast if the EGFR is less than 30

1:58

due to the very small risk

1:59

of contrast nephropathy in patients with moderate

2:01

to severe renal impairment.

2:03

There's also the question about contrast allergy.

2:05

Anytime that we're giving intravenous iodine contrast,

2:07

it's something we've gotta think about.

2:08

And so patients are screened with a contrast questionnaire

2:11

and then if there's relative

2:13

or absolute contraindications including

2:14

that renal impairment

2:15

or previous allergies to contrast,

2:17

then we don't tend to give it.

2:19

And that said, all of our staff, our doctors,

2:21

our technologists and our nurses all have um,

2:23

anaphylaxis training and we have an anaphylaxis management

2:26

plan in our department

2:28

and there's always a doctor on site

2:30

to cover contrast injections.

2:32

Should an allergy occur or a patient requires review.

2:37

Our protocol is we give a 20 m um, hand injection

2:39

of intravenous iodine contrast,

2:41

which at our center is omnipaque three 50.

2:43

Um, and then this is given 20 minutes prior to injections so

2:46

that we get that good delayed phase um, opacification

2:50

of the urinary tract.

2:52

And so this is a patient who has um, come in

2:55

for A-P-S-M-A pet of course. Um, and we're

2:58

Just gonna scroll all the way down to the pelvis here

3:00

and you can see um, just

3:02

as in radiology we've got a ification

3:04

of the collecting systems

3:06

and coming down, um, renal pelvis,

3:09

these have got quite small ureters

3:10

but you can see as we get down here it is here.

3:13

Um, the ureter on the left, there's brighter focus

3:15

of contrast in there, but we're in the regions

3:18

where we've got a lot of vessels

3:19

so we're gonna have a lot of lymph nodes.

3:21

So getting that ureteric delineation can really improve the

3:24

sensitivity and specificity of the examination.

3:26

So coming down

3:27

and we can see that there's a bit

3:29

of bladder wall thickening, um, despite its collapsed state

3:31

'cause the patient has known prostate disease

3:33

and opacification of the bladder

3:36

and we can see the ureters just coming in just a little bit

3:38

bright coming in here to the back.

3:41

So moving on to the next slide.

3:43

You can see this is our fused imaging.

3:45

This kind of can give us a bit more of an idea about

3:48

how useful the contrast is.

3:51

This is a pet rainbow scale, so you'll see

3:53

that I'll use a few different pet scales

3:55

throughout the lectures.

3:57

Um, pet rainbow is the default

3:58

that gets uploaded to our packs.

4:00

So sometimes I've got these, um,

4:01

but I read on the turquoise color scheme

4:04

so you'll see me flip backward and forward between the two.

4:07

But in here, tracer um, accumulation is seen in red,

4:10

so our kidneys naturally are quite bright.

4:12

And here is our ureter here delineated in the red,

4:15

coming down into the pelvis just through there.

4:18

And so this is where it becomes really useful

4:21

because we can see we've got two dots

4:23

and so I wanna know if this is two lymph nodes

4:25

or if this is a ureter and a node.

4:27

And so we have that capability to be able to compare.

4:31

And this is, you can see this is a good example

4:33

of me flicking backward and forward to my color schemes.

4:36

So here is one of the dots

4:38

and then the second one behind as we saw on that rainbow.

4:41

And then I wanna know, is this disease

4:43

or is this physiological?

4:44

And so here is our ureter, which has been opacified

4:47

with the bright white contrast

4:50

and here is the adjacent lymph node just behind it.

4:54

So this is kind of a good example about

4:55

where the opacification of the radio urine, um,

4:58

against the excreted intravenous contrast is really useful,

5:02

um, in proving our diagnostic accuracy with these studies.

5:05

And another really good kind of way to use this is

5:08

for patients who have had prior TURPs

5:10

or transurethral resection

5:11

of the prostate really common in

5:13

our prostate cancer patients.

5:14

Because of the nature of the procedure,

5:17

the prosthetic urethra can be quite capacious

5:19

and it will pull urine in a different way

5:22

to if the procedure hadn't been done.

5:24

And so it can be really tricky to work out

5:26

what is a central tumor and what is urine.

5:29

And so giving the patient contrast can be really helpful.

5:32

And if I pop these two cases side by side, we can see

5:35

that the bright area of uptake is seen as a white area

5:39

of excreted iodine contrast.

5:42

So I can confidently say

5:43

that this is uptake within the terp defect

5:45

and not a site of disease.

5:48

And this is kind of what it looks like on our mip.

5:50

And there it is there. That's the outline of the bladder.

5:52

The way it kind of funnels down towards the bottom

5:55

as seen here on the arrow,

5:56

That is kind of where the turp defect is.

5:59

Um, and then I can match it up

6:01

and as we've seen here, here's another good example really,

6:04

um, high intensity essentially within the prostate

6:07

corresponding to that TURP defect.

6:10

And in this patient as well, they've got an extra thing

6:12

that will, that can help

6:13

with the X-rated iodine Contrast is this

6:16

bladder diverticulum.

6:17

Um, and this is quite bright here,

6:19

but when I did turn it down,

6:21

it almost looked like there was a separate blob,

6:23

especially on the rotating MIP when I read this case.

6:25

And so the use of the intravenous contrast, I pacifying

6:28

that bladder was allowing me to confidently call that

6:31

as a bladder diverticulum, which no doubt occurred

6:34

as a complication of bladder outlet obstruction in the

6:36

setting of prostate disease.