0:00

This was a case that I showed earlier that I want

0:03

to emphasize the concept of a Lucid interval.

0:08

This was the patient who had previous trauma

0:10

that I demonstrated the subdural hematoma,

0:13

the subarachnoid hemorrhage,

0:14

and the soft tissue swelling over the calvarium.

0:19

What I pointed out previously was a small,

0:23

tiny collection that that was present over the right

0:27

temporal lobe. This may just be a blood vessel,

0:30

but on thin-section images, you want to look carefully

0:33

to see where this represents a collection.

0:35

More importantly, on the bone windows,

0:39

as we extend inferiorly,

0:42

you can see the fracture that was involving the mastoid

0:45

and tympanic portions of the temporal bone,

0:48

and then extended superiorly to involve the squamosal

0:53

portion of the temporal bone.

0:55

So, although this was a very subtle finding

0:59

of minimal blood products,

1:01

we had to be concerned about the possibility of an

1:05

epidural hematoma by virtue of the temporal bone fracture.

1:11

By lucid interval,

1:12

we mean that the patient initially does very well and has

1:16

a period of time where you think that the prognosis is

1:20

pretty good because the patient is responsive, et cetera.

1:23

This patient, however,

1:24

deteriorated rapidly over the course of time.

1:28

As you can see by the thin section images

1:32

in soft tissue window,

1:34

the patient developed a large epidural hematoma.

1:40

How do we know it's an epidural hematoma?

1:42

It's lenticular in shape.

1:45

It is associated with that temporal bone fracture

1:50

and it does not cross sutures,

1:52

for example, the coronal suture.

1:55

Remember that there is a 15 millimeter

2:00

size diameter by which the neurosurgeons make

2:04

a decision about whether or not to operate.

2:07

This is 42 mm in size associated with

2:12

right to left shift and an element

2:16

of subfalcine herniation.

2:20

The delayed presentation of this epidural

2:25

hematoma is not unusual,

2:28

particularly when one has the fracture that

2:32

predisposes you to an epidural hematoma.

2:35

This accounts for the "Lucid interval"

2:38

in which the patient initially does well

2:41

and then rapidly deteriorates.

2:45

You will note as well that the uncus is medially deviated,

2:49

suggesting the mass effect is affecting

2:53

the temporal lobe as well.