1/Have some confusion about tumor perfusion?

Do you go into a coma looking at scans for glioma?

Never fear!

Read on for this month's @theAJNR SCANtastic for what you need to know on the latest in brain tumor imaging!

ajnr.org/content/45/4/4…
@TheAJNR 2/Since the prehistoric days of medicine (1979!), we knew that some brain tumor patients treated w/radiation (XRT) initially declined, but then get better.

Today, we see this on imaging, where it looks worse early, but then gets better.

Now we call this pseudoprogression.

1/Having trouble remembering how to differentiate dementias on imaging?

Is looking at dementia PET scans one of your PET peeves?

Here’s a thread to show you how to remember the imaging findings in dementia & never forget! 2/The most common functional imaging used in dementia is FDG PET. And the most common dementia is Alzheimer’s disease (AD).

On PET, AD demonstrates a typical Nike swoosh pattern—with decreased metabolism in the parietal & temporal regions

1/”That’s a ninja turtle looking at me!” I exclaimed.

My fellow rolled his eyes, “Why do I feel I’m going to see this on X or twitter 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 first have to know the anatomy in this region.

I have always thought the medulla looks like a 3 leaf clover in this region.

1/CSF leaks are controversial!

Some say they're overdiagnosed, others underdiagnosed

How can YOU make sure you aren’t under or overdiagnosing?

Are you BERN-ing to know when to suspect CSF leak?

Here’s a 🧵about the CSF leak Bern score so you don’t get BERN-ed by CSF leaks 2/In CSF leaks, everyone knows about brain sagging.

But this can happen w/other diseases, ie Chiari 1.

Other findings can be seen on brain MRI in CSF leaks.

But what are these findings & are some findings more suggestive than others?

Do⬆️findings = ⬆️suspicion?

1/Is remembering cerebellar anatomy making you dizzy?

Need help telling your flocculus from your nodule?

How much cerebellar anatomy do YOU know?

Here’s some help w/an anatomy thread on the 9 lobules of the vermis! 2/Coming from anterior, the first lobule is the lingula

It sticks out from the front of the vermis & is connected to the superior cerebellar peduncle (SCP)

I remember this bc of its very appropriate name—lingula—it looks like a tongue sticking out of the vermis to lick the SCP

1/Time is brain! But what time is it?

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/In ~25% of acute stroke patients, the time of last known well is well, not known.

Then it’s important to use the stroke’s MR imaging features to help date its timing.

Is it hyperacute? Acute? Subacute? Or are the “stroke” symptoms from a seizure from their chronic infarct?

1/Does your ability to remember temporal lobe anatomy seem, well, temporary?

Or are you feeling temporally challenged when it comes to this complex region?

Here’s a thread to help you remember the structures of the temporal lobe! 2/Temporal lobe can be divided centrally & peripherally.

Centrally is the hippocampus.

It’s a very old part of the brain & is relatively well preserved going all the way back to rats.

Its main function is memory—getting both rats & us through mazes—including the maze of life

1/Does trying to diagnose trigeminal neuralgia give you a splitting headache?

Luckily, the answer is written all over your face!

This week's @theAJNR SCANtastic is in your face--showing you how you can visualize trigeminal injury on MR neurography!

ajnr.org/content/45/3/3…
2/As neuroradiologists, we tend to focus on intracranial pathology that may cause trigeminal neuralgia, especially microvascular compression

We often forget that the trigeminal nerve doesn’t stop at the skullbase—and forget to look outside the calvarium

1/The medulla is anything but DULL!

Does seeing an infarct in the medulla cause your heart to skip a beat?

Does medullary anatomy send you into respiratory arrest?

Never fear, here is a thread on the major medullary syndromes! 2/The medulla is like a toll road.

Everything going down into the cord must pass through the medulla & everything from the cord going back up to the brain must too.

That’s a lot of tracts for a very small territory. Luckily you don’t need to know every tract

1/Do questions about laryngeal anatomy leave you speechless?

Is the voice box a black box for you?!

Do you feel like you're beating a dead horse when it comes to understanding hoarseness?

Let me help you find your voice w/ this introductory thread on laryngeal anatomy! 2/Everyone needs some support

Tongue is supported by the hyoid

Larynx is supported by the cricoid cartilage

Cricoid for the larynx is like your favorite chair for you--supports you & holds that drink you need

Cricoid provides support & also holds everything the larynx needs

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 the images & let RAPID read the perfusion for you?

Not anymore!

Here's all you need to understand perfusion imaging! 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.

1/Can’t seem to strike the right CHORD when it comes to chordomas?

Do chordomas frighten you to the core?

What do you KNOW about the NOTOchord?

Never fear, here’s a thread to teach you what you NEED to know about the diagnosis & treatment of chordomas! @BernardBendokMD 2/Chordomas arise from remnants of the notochord.

The notochord is an embryologic structure.

Think of the notochord like a bunch of seeds scattered next to the embryonic neural tissue, waiting to grow.

1/Does PTERYGOPALATINE FOSSA anatomy feel as confusing as its spelling?

Does it seem to have as many openings as letters in its name?

Are you pterrified of the pterygopalatine fossa (PPF)?

Let this thread on PPF anatomy help you out! 2/The PPF is a crossroads between the skullbase & the extracranial head and neck. There are 4 main regions that meet here.

The skullbase itself posteriorly, the nasal cavity medially, the infratemporal fossa laterally, and the orbit anteriorly.

1/Feeling unarmed when it comes to evaluating cervical radiculopathy & foraminal narrowing on MRI?

Is reading c-spine MRIs becoming a pain in the neck?

Here’s a thread that’ll take that weight off your shoulder & show you how to rate cervical foraminal stenosis! 2/First, the anatomy.

Nerve rootlets arise from the anterior & posterior horns, merging to form anterior (motor) & dorsal (sensory) nerves roots in the thecal sac.

These come together & the dorsal root has its dorsal root ganglion before the spinal nerve extends extravertebral.

1/Talk about dangerous liaisons!

Abnormal brain vascular connections can be dangerous!

One of the most important abnormal connections is a dural arteriovenous fistula (dural AVF)

Here’s a thread to give you some durable knowledge about dural AVFs! @BernardBendokMD 2/Dural sinuses sit inside dural leaflets.

Arteries that feed the dura also feed the walls of sinuses, like vasa vasorum.

Arteries in the walls of veins are a natural connection between the veins and arteries—but these connections are usually closed in normal pts.

1/They say form follows function!

Brain MRI anatomy is best understood in terms of both form & function.

Here’s a thread to help you to remember important functional brain anatomy 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.

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! 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!

1/Talk about twisting your back!

Do spine vascular lesions make your brain feel as tangled as the dilated vessels you see?

Want some information on malformations?

Here’s a thread on spine vascular anatomy to give you durable knowledge on dural arteriovenous fistulas (dAVF) 2/To understand spinal dural AVFs, you need to understand basic spinal vascular anatomy.

The spine is LONG—to get blood from the top to the bottom is like going through the length of a marathon course

1/Haunted by questions about stroke imaging?

Don’t stand a ghost of chance w/perfusion imaging?

Do you know what a ghost infarct core is?

Strokes can’t vanish! Or can they?

Find out in this week’s @TheAJNR SCANtastic thread!

ajnr.org/content/early/…
2/Purpose of mechanical thrombectomy is to save tissue that is still alive in the face of a large vessel occlusion

It’s like firefighters running into a burning building—they are only going to go in if someone is still alive to be rescued

Otherwise, it’s not worth the risk.

1/Is your understanding of medial temporal anatomy, well, temporary?

If only there was a way to make hippocampal anatomy memorable!

Here is a thread of the basics of hippocampal anatomy that will hopefully stay in your hippocampus! 2/Its name “hippocampus” comes from its shape on gross anatomy.

Early anatomists thought it looked like an upside down seahorse—w/its curved tail resembling the tail of a seahorse.

Hippocampus literally means seahorse.

1/Want to understand skull base surgery?

Just follow your nose!

Endoscopic endonasal approach (EEA) through the nose is becoming standard

Do YOU know what to look for in these patients?

Answer is right under your nose in this thread about EEA from Contemporary Neurosurgery! 2/EEA is involves inserting a scope and instruments through the nose to access the skullbase.

It allows access to the skull base without the need for traction on the brain like traditional open transcranial surgery

It’s basically the ultimate nose picking!