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! 😜
• • •
Missing some Tweet in this thread? You can try to
force a refresh
@TheAJNR 2/In the lumbar spine, it is all about the degree of canal narrowing & room for nerve roots.
In the cervical spine, we have another factor to think about—the cord.
Cord integrity is key. No matter the degree of stenosis, if the cord isn’t happy, the patient won’t be either
@TheAJNR 3/Cord flattening, even w/o canal stenosis, can cause myelopathy.
No one is quite sure why.
Some say it’s b/c mass effect on static imaging may be much worse dynamically, some say repetitive microtrauma, & some say micro-ischemia from compression of perforators
1/Do radiologists sound like they are speaking a different language when they talk about MRI?
T1 shortening what? T2 prolongation who?
Here’s a translation w/an introductory thread to MRI.
2/Let’s start w/T1—it is #1 after all! T1 is for anatomy
Since it’s anatomic, brain structures will reflect the same color as real life
So gray matter is gray on T1 & white matter is white on T1
So if you see an image where gray is gray & white is white—you know it’s a T1
3/T1 is also for contrast
Contrast material helps us to see masses
Contrast can’t get into normal brain & spine bc of the blood brain barrier—but masses don’t have a blood brain barrier, so when you give contrast, masses will take it up & light up, making them easier to see.
1/Asking “How old are you?” can be dicey—both in real life & on MRI! Do you know how to tell the age of blood on MRI?
Here’s a thread on how to date blood on MRI so that the next time you see a hemorrhage, your guess on when it happened will always be in the right vein!
2/If you ask someone how to date blood on MRI, they’ll spit out a crazy mnemonic about babies that tells you what signal blood should be on T1 & T2 imaging by age.
But mnemonics are crutch—they help you memorize, but not understand. If you understand, you don’t need to memorize
3/If you look at the mnemonic, you will notice one thing—the T1 signal is all you need to tell if blood is acute, subacute or chronic.
T2 signal will tell if it is early or late in each of those time periods—but that type of detail isn’t needed in real life
Here's a little help on how to do it yourself w/a thread on how to read a head CT!
2/In bread & butter neuroimaging—CT is the bread—maybe a little bland, not super exciting—but necessary & you can get a lot of nutrition out of it
MRI is like the butter—everyone loves it, it makes everything better, & it packs a lot of calories. Today, we start w/the bread!
3/The most important thing to look for on a head CT is blood.
Blood is Bright on a head CT—both start w/B.
Blood is bright bc for all it’s Nobel prizes, all CT is is a density measurement—and blood is denser (thicker) than water & denser things are brighter on CT
MMA fights get a lot of attention, but MMA (middle meningeal art) & dural blood supply doesn’t get the attention it deserves.
A thread on dural vascular anatomy!
2/Everyone knows about the blood supply to the brain.
Circle of Willis anatomy is king and loved by everyone, while the vascular anatomy of the blood supply to the dura is the poor, wicked step child of vascular anatomy that is often forgotten
3/But dural vascular anatomy & supply are important, especially now that MMA embolizations are commonly for chronic recurrent subdurals.
It also important for understanding dural arteriovenous fistulas as well.