What are you worried about in setting of trauma?

Bleed, fracture, increased ICP

We will get to the blood...

but the MOST IMPORTANT thing about this CT scan is the EFFACED BASAL CISTERNS:

The CSF spaces around the brainstem are called the BASAL CISTERNS.

Normally, there SHOULD be some CSF in front of the brainstem (arrows) here, around the brainstem here, and again around the brainstem here, but in this case, there isn't.

No CSF in the basal cisterns = EFFACED basal cisterns (technical term).

CSF on CT is a very dark gray, almost black. There should be black around the brainstem, but there is none in this patient.

There is no CSF in this patient's basal cisterns because it's been squished away by the mass effect from the left cerebellar intraparenchymal hemorrhage.

Effaced basal cisterns are VERY BAD = pressure on the brainstem = brainstem ischemia -----> need immediate action to lower ICP.

➜ The lesson here is that you ALWAYS need to look at the basal cisterns!

What other abnormalities did you find?

Yes, there's a lot going on in this scan.

One of the things you likely saw was the intraparenchymal blood in the left cerebellum.

There's a touch of subdural hematoma.

There's a bit of subarachnoid hemorrhage.

And there's a left occipital bone fracture that extends down to the skull base.

We all care about seeing whether there is bleeding or not in the brain after trauma, and we should care about that. But we often forget to look at the basal cisterns and decide if they are open or effaced.

If they are effaced, that's something that we as EM docs should know about and start countermeasures to lower ICP.

Start thinking of how you would make a heuristic out of this:

In the setting of: 

Do this: 

And look:

Now let's look at another patient's scan.