0:01

Let's contrast that previous case from this child who

0:07

also has a fat containing lesion in the spinal canal.

0:11

We have T1-weighted scan, T2-weighted scan,

0:13

and STIR imaging of the lumbar spine.

0:18

So the lesion is bright in signal intensity

0:21

on the T1-weighted scan simulating fat,

0:25

ad on the STIR imaging where the fat has been suppressed,

0:28

the lesion suppresses. So, we know it's a lipoma.

0:32

even if we didn't have the STIR imaging, however,

0:36

we would have a good indication that this is fat

0:39

containing as opposed to high protein or melanin

0:44

containing or enhancement by virtue of the chemical

0:49

shift artifact that I described previously,

0:52

at the border of the lesion with this darker rim as a

0:56

frequency shift associated with the different

0:59

frequency at which fat precesses versus CSF.

1:03

So we have a lipoma.

1:05

This one is anteriorly located.

1:07

But importantly,

1:08

this patient also has a low lying spinal cord, right?

1:12

So we have the...

1:14

we're at, maybe this is five, and this is L4,

1:16

and this is L3, L2, L1.

1:18

So you have cord tethering with this lipoma.

1:23

If we go further and count the number of sacral

1:27

segments, we note that there's an S1, an S2, and S3,

1:32

and then we sort of kind of lose the development

1:35

of the lower sacrum and coccyx.

1:37

So this patient's congenital malformation is associated

1:42

with this lipoma and the tethered cord.

1:45

Let's just scroll a little bit more from side to side.

1:49

You want to look for whether or not there are posterior

1:52

elements that are intact to also identify whether

1:56

there is spinal dysraphism. In this case,

1:59

the posterior elements are intact,

2:01

but the lower sacrum and coccyx

2:03

have not been well developed.

2:04

You also want to look in the subcutaneous fat.

2:07

And this sometimes requires windowing at different

2:11

levels to see whether or not there is a tract leading

2:14

from the skin surface to this lipoma

2:17

or to the end of the spinal cord.

2:19

We note also that there is fat down here, which is

2:23

suppressing more posteriorly. So in this area

2:26

where the sacrum has not been well developed,

2:28

you also have prominence to the posterior epidural fat,

2:34

which is separate from the lipoma more anteriorly.