0:00

I wanted to use this next case to show the

0:04

potential beneficial effects of dynamic MRA,

0:08

or twist imaging of the spinal canal.

0:11

When one knows one is evaluating

0:14

a vascular malformation.

0:16

Here on this patient's T2-weighted MRI scan,

0:20

we see that there is a vascular malformation

0:23

which is outside the spinal cord.

0:25

So not your type II vascular malformation.

0:28

This may, in point, in fact,

0:29

if it's a fistula outside the spinal cord,

0:33

it would be a type IV vascular malformation.

0:36

Or it may be one of these CONUS vascular

0:39

malformations. In any case,

0:41

the cord is displaced posteriorly

0:43

by the vascular malformation.

0:45

And if we look at this on

0:47

the T2-weighted scans,

0:50

we can see the

0:53

enlarged blood vessels in the

0:56

cauda equina nerve roots

0:59

and

1:00

Anterior to the spinal cord,

1:02

not within the spinal cord where

1:04

the malformation is located.

1:09

So for the evaluation of the patient with

1:16

dynamic MRA, one usually sets this up in either

1:22

the sagittal or the coronal plane depending upon

1:25

then the degree of the patient's kyphosis.

1:28

So, sagittal is good because you have a

1:31

relatively narrow transverse

1:32

width of the spinal canal.

1:34

But if the patient has a relatively minor

1:38

thoracic kyphosis or lumbar lordosis,

1:40

you can do this also

1:43

in the coronal plane. In any case,

1:45

this is the pre-contrast sequence, and then

1:50

the post-contrast sequence again.

1:52

So that way, you can do a subtraction technique.

1:55

And with this

1:59

dynamic injection of contrast,

2:01

we can also take multiple phases so that we're

2:04

in both the arterial phase as well as in

2:06

the venous phase as we go through.

2:08

So initially, you see the aorta,

2:11

and then towards the end,

2:12

you're going to see some of the venous system

2:18

on the MRA raw data.

2:21

Next,

2:22

you can construct this in either the coronal

2:26

plane or the sagittal plane.

2:28

In this instance,

2:29

what one sees is the aortic arch.

2:31

With the super aortic vessels.

2:33

And then, if we were to count down,

2:35

we would be able to identify which of these

2:38

intercostal arteries is the one that's likely

2:41

to be feeding it, and of course,

2:42

it's going to be the largest one.

2:44

And that would identify which level to go to,

2:48

either on conventional arteriography if you

2:50

for treatment or to direct the surgeon.

2:53

Not uncommonly,

2:54

you have that hairpin loop of the large

2:58

anterior spinal artery from

3:00

the artery of adding caveats,

3:02

which may be an anatomic structure you want

3:05

to be sure that you're identifying.

3:07

So that way, you don't have a complication of a

3:09

cord infarct. Once you have a 3D data set,

3:13

you can reconstruct it in a coronal or in

3:15

an axial plane. On the coronal plane,

3:17

we get the sense that this is

3:18

a lesion that is eccentric.

3:22

As far as the

3:24

loop, slightly to the right of midline,

3:27

but a little bit worried about the enlargement

3:30

of the blood vessels on the left

3:31

hand side of the aorta here.

3:35

So this is the aorta with the iliac bifurcation

3:39

and the vascular malformation.

3:43

And this reconstruction can be done in any

3:47

number of planes to better define the anatomy.

3:50

Most of the time,

3:51

what we're using this for is to try to either

3:54

limit the extent of the spinal angiogram that

3:58

is required, particularly in a child.

4:00

Since we want to limit the irradiation of the child, and if we had to go through every intercostal and lumbar level as well as vertebral arteries and bronchial arteries, as well as iliac arteries and spinal arteries, it would lead to a lot of radiation to the child.

4:03

The child and if we had to go through every

4:04

intercostal and lumbar level as well as

4:07

vertebral arteries and bronchial arteries,

4:10

as well as iliac arteries and spinal arteries,

4:14

it would lead to a lot of

4:15

radiation to the child.

4:17

Sometimes these MRAs can isolate where the likely vessel is, and we can do a more directed scan in. Alternatively,

4:21

if we actually make that diagnosis,

4:24

we can go directly to treatment with the basis of the MRA.

4:26

If we actually make that diagnosis,

4:29

we can go directly to treatment with the basis of the MRA.

4:33

Basis of the MRA.