Lea Alhilali, MD Profile picture
Nov 11, 2022 12 tweets 8 min read Read on X
1/They say form follows function! Brain #MRI anatomy is best understood in terms of both form & function

A #tweetorial on how to remember important functional #brain #anatomy

#meded #medtwitter #neurosurgery #neurology #neurorad #FOAMed #FOAMrad #radiology #medstudent #radres
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
 

Keep Current with Lea Alhilali, MD

Lea Alhilali, MD Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @teachplaygrub

May 20
1/Correlate clinically!

It’s harder than you think in THALAMUS—where its size is small & but the clinical symptoms are large.

Here’s a thread to help you remember the main thalamic syndromes & their locations! Image
2/Thalamus is a dense network of nuclei & tracts connected to almost everything in the brain. So almost any symptom can be correlated to it.

So saying “thalamus” as the answer when asked where a lesion is located is always reasonable—even w/o knowing what the symptoms are! Image
3/Think of the thalamus like the internet service provider or ISP for the brain.

Like an ISP, everywhere is connected through it. And like an ISP, things go bad when it goes down.

But just like an ISP, the problems created depend on where in the network the outage is located. Image
Read 23 tweets
May 17
1/ I always say, "Anyone can see the bright spot on diffusion images—what sets you apart is if you can tell them why it’s there!”

If you don't why a stroke happened, you can't prevent the next one!

Can YOU tell a stroke’s etiology from an MRI?

Here’s a thread to show you how! Image
2/First a review of the vascular territories.

I think the vascular territories look a butterfly—w/the ACA as the head/body, PCA as the butt/tail, and MCA territories spreading out like a butterfly wings. Image
3/Of course, it’s more complicated than that.

Medially, there are also small vessel territories—the lenticulostriates & anterior choroidal.

I think they look like little legs, coming out from between the ACA body & PCA tail. Image
Read 25 tweets
May 14
1/Got the diagnosis when it comes to vessel stenosis?

Or is your knowledge narrow when it comes to vessel narrowing?

When it comes to vasospasm, do you know why it happens or what to look for?

Here is the thread you NEED to unravel why vessels twist up! Image
2/Vasospasm results from subarachnoid hemorrhage (SAH) & a buildup of multiple factors

It’s like how you can handle 1 nag from your boss on Monday—but after nagging all week, you break down on Friday!

Same w/vasospasm—it doesn’t happen until the end of the week after SAH! Image
3/So what is nagging that causes the vessel to shut down?

When the body breaks down blood from SAH, it releases free heme

And this free heme causes a cascade of negative consequences, call heme-related inflammation

So free heme is the annoying boss! Image
Read 21 tweets
May 13
1/ “Now listen carefully!”

Everyone has so much fear about the anatomy where they hear!

Do you dread temporal bone anatomy?

Do find the understanding ossicles impossible?

Do you know the ice cream cone sign on CT & then nada?

Then you need this thread on ossicular anatomy! Image
2/For the middle ear, I have a rule of 3s.

Middle ear is divided into 3 parts & it contains 3 ossicles.

Today we will focus on the ossicles—each of which has 3 parts! Image
3/First ossicle you meet when you enter the middle ear is the malleus.

It’s called the malleus because it acts like a mallet that hits a drum—literally—the ear drum!

I think it looks like Dr. Evil’s mini me, with its short body and round bald head Image
Read 19 tweets
May 10
1/Have disagreements between radiologists on the degree of cervical canal stenosis become a pain in the neck?!

Worried about sticking your neck out and calling severe cervical stenosis?

Here’s a thread on cervical stenosis grading that’s easy, reproducible & evidence based! Image
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 Image
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 Image
Read 18 tweets
May 8
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!

After reading this, when you see a hemorrhage, your guess on its age will always be in the right vein! Image
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 Image
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

So let’s look at T1 Image
Read 21 tweets

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Don't want to be a Premium member but still want to support us?

Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal

Or Donate anonymously using crypto!

Ethereum

0xfe58350B80634f60Fa6Dc149a72b4DFbc17D341E copy

Bitcoin

3ATGMxNzCUFzxpMCHL5sWSt4DVtS8UqXpi copy

Thank you for your support!

Follow Us!

:(