0:00

Here, we have an ultrasound image for a patient

0:03

who is status post renal transplant

0:06

and we're asked to evaluate the alligraph. And so we're

0:09

using ultrasound as our first line Imaging modality to

0:12

do so, it's important to remember that with ultrasound. We

0:15

typically can use high frequency transducers about five

0:18

megahertz to evaluate with these renal transplants due to

0:21

the relatively superficial location in the pelvis. If

0:24

you see this transplant here, this is really right

0:27

beneath the abdominal wall. And so these high frequency transducers

0:30

can really evaluate them very nicely. Now the

0:33

first thing I do when I look at these renal transplants is evaluated

0:36

gray scale appearance and sometimes the

0:39

cortical mentally differentiation give me a little bit more pronounced due

0:42

to the superficial or relative superficial

0:45

location of the renal transplant, which is essentially right

0:48

beneath the transducer in this instance. Look at

0:51

the gray scale image. You measure the transplant and it's

0:54

length

0:55

You look for evidence for hydronephrosis. We shouldn't

0:58

really see hydronephrosis, but it is important to remember

1:01

that you sometimes may see a mild amount of fullness the

1:04

renal collecting systems, which is expected to be within normal

1:07

range of its very mild. There are many reasons why this

1:10

can happen one reason is that you know,

1:13

you essentially have now one kidney doing the work of two so you

1:16

generally have more fullness in the renal collecting system. You also

1:19

have a relative loss of autonomic innervation in

1:22

these renal collecting systems such that can't necessarily regulate when

1:25

it needs to empty. It's collecting systems

1:28

into the bladder and so generally tends to be a little bit more Fuller and

1:31

so on the grayscale image, I'm just looking for big abnormalities

1:34

mass is collection. I measure the length of

1:37

the kidney I move on to color images and it's important to demonstrate

1:40

there's color flow throughout the renal transplant and there's

1:43

any focal areas of Lack of Color flow. You

1:46

really should interrogate that and figure out why there's no flow in

1:49

that region. You can use color doppler images you can use more sensitive

1:52

techniques to flow. So just powered up imag

1:55

as well

1:57

Here we have some more grayscale images looking in the transverse plane

2:00

of the kidney and then you start to evaluate some

2:03

of the intraprenchymal renal arteries using color and

2:06

spectral Doppler Imaging.

2:08

And you're really looking at upper pull arteries and lower pole arteries.

2:11

So here's his annotated right lower quadrant upper pull

2:14

at the level of the second mental renal arteries in

2:17

which you want to see is these nice relatively low

2:20

resistance waveform with Sharps histolic up

2:23

strokes and continued flow throughout diastole. We

2:26

do also measure resistive indices in real transplant

2:29

patients Within These parental arteries

2:32

resistive Indus is really a measure of the vascular resistance

2:35

within some of these vessels and it's calculated by

2:38

taking the peaksystolic velocity subtracting it

2:41

in the end diastolic velocity and dividing at all

2:44

over the peak systolic velocity.

2:47

And so when you do that ratio over here, you're going

2:50

to get in this instance 0.56. And normally anything from

2:53

0.5 to 0.7 is appropriate

2:56

for the renal transplant. And so

2:59

we interrogate in different areas here. We have the upper pole segmental artery.

3:02

That's interrogated. Here we go to some of the other arteries here

3:05

that are interrogated and we also similarly try

3:08

to look at the veins and you want to make sure there's nice venous flow

3:11

throughout the transplanted. Kidney and here we're

3:14

going to the lower pole segmental, you know arteries lower pulse mental

3:17

renal veins.

3:19

Sometimes it's very difficult to differentiate the arteries and

3:22

veins which are very small and adjacent to each other. So here in

3:25

this particular slice. We have waveforms from

3:28

both the artery as well as the vein but there is nice venous

3:31

flow throughout this transplanted kidney. These are some

3:34

of the other arteries here that showing good systolic upstrokes with

3:37

appropriate resistive indices.

3:40

Thereafter we look at the main renal artery in

3:43

the main renal vein and here we can see the main renal artery In

3:46

Vein adjacent to one another.

3:47

Main renal vein has appropriate flow. It's

3:50

monophasic. It may be slightly pulsatile, depending

3:53

on the cardiac status of the patient.

3:55

And there's no real normal threshold for what velocities we

3:58

except for these renal transplants in the main renal vein. So

4:01

we generally just sort of compare different segments and see

4:04

if there's any major differential between them.

4:07

Here we're evaluating the main real artery and we

4:10

really evaluated at least three different segments including

4:13

the higher region, which we have a velocity of

4:16

152.

4:17

More distally with a velocity of 164 mid

4:20

portion at 184 and then right

4:23

at the anastomosis at 176 and in each of

4:26

these we're seeing a nice systolic upstroke with Continuous Flow throughout diastole.

4:29

So these are completely appropriated waveforms for

4:32

the main renal artery.

4:35

We're also going to be evaluating the external iliac artery both beyond the

4:38

anastomosis this instance velocity of 132. And

4:41

then just prior to the anastomosis velocity

4:44

of 134 and to

4:47

evaluate if there's any stenosis or really abnormal narrowing of

4:50

the main renal artery. We're really looking at ratios and so once we

4:53

have all these velocities we try to see if there's

4:56

a differential ratio typically of 3.5 to

4:59

1 if there is an increase in that velocities across

5:02

different segments, we consider that there to be

5:05

some abnormality with the renal artery some narrowingers stenosis.

5:09

We're also going to evaluate the external iliac veins to ensure

5:12

that there's good flow throughout it. And finally we get some grayscale

5:15

images of the bladder to make sure there's no clear bladder abnormalities.