0:00

This is a 66-year-old man known

0:03

to me on Parkinson's therapy,

0:06

switched to another therapy upon which the

0:10

diagnosis of a possible stroke was entertained,

0:13

and therefore he got diffusion imaging,

0:16

which was negative, by the way,

0:18

did not show evidence of a stroke.

0:21

And most likely his symptoms were related to

0:25

tardive dyskinesia with the development of

0:27

choreoathetosis, secondary to the new medication.

0:31

Now, on the EPI image,

0:33

you can see very close opposition of the

0:36

red nuclei to the substantia nigra.

0:40

And the substantia nigra is thickened from

0:43

anterior to posterior due to accumulation

0:46

of iron in the compacta region.

0:48

Now, this is not as easily appreciated

0:51

or not as specifically identified as it

0:54

is in the middle image,

0:56

which is a blood iron-sensitive sequence

0:59

known as blood-sensitive imaging,

1:01

BSI, SWAN, or SWI,

1:05

susceptibility-weighted imaging.

1:08

When we look at this image,

1:10

we see right there that there is a paucity

1:12

of iron in the red nucleus.

1:14

So there's depigmentation of the red nucleus.

1:17

The compacta stripe is very thin on one cut

1:20

and on the next cut, the two absolutely,

1:23

positively bleed together.

1:25

Then in the lateral aspect of the nigra,

1:28

maybe there's a little bit of a swallowtail here,

1:30

but there's not much of a swallowtail on the

1:33

patient's right side, the viewer's left.

1:36

And the iron distributions and stores

1:39

are completely blunted.

1:41

Now, on the diffusion tensor image,

1:44

attenuation of the white matter tracks posteriorly

1:48

due to visual spatial agnosia and loss of visual

1:52

spatial function is not specific

1:54

to Parkinson's disease.

1:56

It's seen in dementia with Lewy bodies,

1:59

as well as classic Parkinson's disease,

2:02

although some have described it as a more

2:05

severe attenuation seen in LBD.

2:08

So we've got three findings here, at least.

2:12

Attenuation of the white matter tracks in the

2:15

visual spatial pathway,

2:17

bleeding together of the rubro nigral interface

2:23

with loss and thinning of the compacta zone,

2:26

and loss of iron in the outer half

2:29

to outer third of the substantia

2:32

nigra with loss of the normal wispy swallow

2:35

tail in the lateral aspect of the midbrain.