2/Let’s start at the top. At the vertex is the superior frontal gyrus. This is easy to remember, bc it’s at the top—and being at the top is superior. It’s like the superior king at the top of the vertex.
3/It is also easy to recognize on imaging. It looks like a big thumb pointing straight up out of the brain. I always look for that thumbs up when I am looking for the superior frontal gyrus (SFG)
4/The SFG contains the supplementary motor area or SMA. As the name suggests, SMA contains a motor region—but not as expected, it also contains a verbal area. I remember that the motor portion is behind the language area bc we all walk before we talk, so motor comes before verbal
5/Next to the superior frontal gyrus is the middle frontal gyrus. It is important for verbal memory. I think it looks like the knuckles of a hand
6/So every time I read a brain MRI, I look at the vertex for the hand giving me the thumbs up. The thumb is the superior frontal gyrus, and next to it, the curved knuckles of the middle frontal gyrus
7/The superior frontal gyrus crashes into the motor strip or pre central gyrus. This is how I like to find the motor cortex. I follow the thumb back until it crashes into a gyrus—and I know that gyrus is the motor strip
8/The motor area of the superior frontal gyrus is right next to the motor cortex. I remember this bc when two cars crash head on, it’s their motors that crash into each other—so the motor area of the SMA crashes into the main motor strip.
9/You can confirm the motor strip by looking for the hand motor region. This is uniquely shaped like an Omega. You can remember that the hand motor region is shaped like an Omega bc Omega is a fancy watch brand and you wear watches near your hand
10/Motor strip goes into to the paracentral lobule, which connects the motor strip & main sensory strip. I think it looks like the “C” on Coach brand purses. I remember this bc this is eloquent cortex, some might say elegant—& elegant people own fancy brands like Coach & Omega
11/Finally, the cortex behind the sensory strip is the superior parietal lobule. It is the butt of the functional regions at the vertex. It is important for spatial orientation and hand function—so it makes sense that it sits right behind the hand motor and sensory cortices
12/So on every brain MRI I read, I go to the vertex & look for:
1. A thumbs up
2. Luxury brands around the eloquent cortex
3. The functional cortex backside (superior parietal lobule)
Hopefully, you will now be eloquent when it comes to functional brain anatomy! 😜
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3/At its most basic, you can think of the PPF as a room with 4 doors opening to each of these regions: one posteriorly to the skullbase, one medially to the nasal cavity, one laterally to the infratemporal fossa, and one anteriorly to the orbit
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.
1/”That’s a ninja turtle looking at me!” I exclaimed. My fellow rolled his eyes at me, “Why do I feel I’m going to see this a thread on this soon…”
He was right! A thread about one of my favorite imaging findings & pathology behind it
2/Now the ninja turtle isn’t an actual sign—yet!
But I am hoping to make it go viral as one. To understand what this ninja turtle is, you have to know the anatomy.
I have always thought the medulla looks like a 3 leaf clover in this region.
The most medial bump of the clover is the medullary pyramid (motor fibers).
Next to it is the inferior olivary nucleus (ION), & finally, the last largest leaf is the inferior cerebellar peduncle.
Now you can see that the ninja turtle eyes correspond to the ION.
3/But why are IONs large & bright in our ninja turtle?
This is hypertrophic olivary degeneration.
It is how ION degenerates when input to it is disrupted. Input to ION comes from a circuit called the triangle of Guillain & Mollaret—which sounds like a fine French wine label!