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More from @teachplaygrub

Lea Alhilali, MD

@teachplaygrub

Jun 26

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/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

Read 10 tweets

Lea Alhilali, MD

@teachplaygrub

Jun 1

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

3/The swoosh rapidly tapers anteriorly—& so does hypometabolism in AD in the temporal lobe. It usually spares the anterior temporal poles.

So in AD look for a rapidly tapering Nike swoosh, w/hypometabolism in the parietal/temporal regions—sparing the anterior temporal pole

Read 16 tweets

Lea Alhilali, MD

@teachplaygrub

May 1

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.

Read 20 tweets

Lea Alhilali, MD

@teachplaygrub

Apr 30

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

3/Peripherally is the neocortex.

Although rats also have neocortex, theirs is much different structurally than humans.

So I like to think of neocortex as providing the newer (neo) functions of the temporal lobes seen in humans: speech, language, visual processing/social cues

Read 12 tweets

Lea Alhilali, MD

@teachplaygrub

Mar 25

1/How low can you go??

All the hype nowadays is about high field MRI, but what about low field??

Read on for this month’s @theAJNR SCANtastic for what to know about what may be the next biggest thing in MRI!

ajnr.org/content/47/3/7…

2/The growing strength is for larger & larger field strengths for higher & higher resolution

So why would we possible go backwards to lower field strength?

Turns out there are some advantages.

3/Low field strength magnets are much for flexible

They can be put in non-traditional settings (clinics) & can also possibly be moved to the bedside

It is truly POC MRI!

But how does it perform?

Read 11 tweets

Lea Alhilali, MD

@teachplaygrub

Jan 27

1/The hardest thread yet! Are you up for the challenge?

How stroke perfusion imaging works!

Ever wonder why it’s Tmax & not Tmin?

Here’s what to know from @theAJNR SCANtastic!

ajnr.org/content/47/1/28

@TheAJNR 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.

@TheAJNR 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.

Read 19 tweets

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Lea Alhilali, MD

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