2/When I look at the skullbase veins, I see an angry Santa yelling at me. His eyebrows are raised, his mouth is open, & he has a mustache w/a big beard hanging down.
Each I look at the skullbase, I look for this Santa—bc each part of him is an important venous structure.
3/So let’s start w/Santa’s eyes. The eyes are actually not a venous structure, but an important landmark—foramen ovale, where the V3 trigeminal nerve exit.
I remember ovale is Santa's eyes bc eyes are OVAL, so his eyes are OVALE
4/Next are Santa’s angry raised eyebrows. These are the sphenoparietal sinuses.
I remember these are the eyebrows bc I call them “seen”-oparietal sinuses & you see w/your eyes.
These have this “eyebrow” shape bc they are following the curve of the greater sphenoid wing
5/Sphenoparietal sinuses meet in the middle at the cavernous sinus—like your eyebrows meet in the middle at your nose.
I remember the cavernous sinus & intracavernous sinuses are Santa’s nose bc you dig in a cavern. And where do all kids like to go digging? Their nose! 🤢
6/Right below Santa’s nose is his mustache & this is the basilar plexus, right below the cavernous sinus.
You can remember this bc mustaches are made of a base & handlebars—and the BASE of Santa’s mustache is the BASilar plexus
7/Extending from Santa’s mustache is his beard. These are the petrosal sinuses (inferior & superior), important in many neurosurgical approaches.
You can remember that the PETROsal sinuses make up sides of the beard bc you use PETROleum to smooth the sides of your beard
8/Finally, Santa’s mouth is the marginal sinus. I remember this bc the word marginal sounds like “Aaaargh”—the sound pirates make from their mouth. I call it the Maaaargh—inal sinus
So hopefully this thread has given you some ELF-confidence when it comes to skullbase anatomy!
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@TheAJNR 2/Everyone knows about the spot sign for intracranial hemorrhage
It’s when arterial contrast is seen within a hematoma on CTA, indicating active
extravasation of contrast into the hematoma.
But what if you want to know before the CTA?
@TheAJNR 3/Turns out there are non-contrast head CT signs that a hematoma may expand that perform similarly to the spot sign—and together can be very accurate.
1/My hardest thread yet! Are you up for the challenge?
How stroke perfusion imaging works!
Ever wonder why it’s Tmax & not Tmin?
Do you not question & let RAPID read the perfusion for you? Not anymore!
2/Perfusion imaging is based on one principle: When you inject CT or MR intravenous contrast, the contrast flows w/blood & so contrast can be a surrogate marker for blood.
This is key, b/c we can track contrast—it changes CT density or MR signal so we can see where it goes.
3/So if we can track how contrast gets to the tissue (by changes in CT density or MR signal), then we can approximate how BLOOD is getting to the tissue.
And how much blood is getting to the tissue is what perfusion imaging is all about.
If you don’t know the time of stroke onset, are you able to deduce it from imaging?
Here’s a thread to help you date a stroke on MRI!
2/Strokes evolve, or grow old, the same way people evolve or grow old.
The appearance of stroke on imaging mirrors the life stages of a person—you just have to change days for a stroke into years for a person
So 15 day old stroke has features of a 15 year old person, etc.
3/Initially (less than 4-6 hrs), the only finding is restriction (brightness) on diffusion imaging (DWI).
You can remember this bc in the first few months, a baby does nothing but be swaddled or restricted. So early/newly born stroke is like a baby, only restricted