1/Sometimes the tiniest thing can be the biggest pain—that’s microvascular compression of the trigeminal nerve! But seeing such a tiny finding can be hard!

Here’s a 🧵 about how to look at the trigeminal nerve on MRI. #medtwitter #neurotwitter #neurorad #meded #FOAMed #HNrad Image
2/The most important thing to remember is that the nerve is 3D so you have to look for compression in all 3 planes. Let’s start w/the axial plane. On a normal axial, the trigeminal nerves should look like the arms of an alien sticking out of the pons. Image
3/Compression in the axial plane usually will deviate the nerve laterally—making it so that the Alien looks like he is flexing one of his arms. So if you see the Alien trying to show his guns—that’s microvascular compression! Image
4/In the sagittal plane, the nerve looks like an elephant’s trunk coming out of the pons. It should have a smooth curve up and over before it enters Meckel’s cave, just like the way an elephant’s trunk curves. Image
5/If the trunk is flattened, like it’s balancing ball or is curved downwards—that’s microvascular compression in the sagittal plane. If the nerve is pressed downward, you could miss this in the axial plane—bc the movement is parallel to the axial plane. You need a sagittal view Image
6/In the coronal plane, the nerves look like two gun barrels pointed at you, by a very potty bellied cowboy that is the pons. Image
7/If the nerves lose their gun barrel shape, and looks more like a boomerang—in any direction—that is microvascular compression. Coronal is usually the most helpful view, bc you can see movement both up and down and left to right. Image
8/So now you know what the normal trigeminal nerve looks like in all 3 planes—and you can now check for microvascular compression in three dimensions. Remember, images may be 2D, but life—and pathology—are 3D! Image

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More from @teachplaygrub

Sep 27
1/ Talk about dangerous liaisons! Abnormal brain vascular connections can be dangerous
A #tweetorial about an important abnormal connection: dural arteriovenous fistulas (dural AVF) in collaboration w/ @SVINJournal!

Featuring this 🆓#openaccess article: ahajournals.org/doi/10.1161/SV… Image
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. Image
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Sep 19
1/Need help reading spine imaging? I’ve got your back!
A #tweetorial about the ABCs of reading spine MRs & CTs.
#medtwitter #FOAMed #FOAMrad #medstudenttwitter #medstudent #neurorad #radres #neurosurgery #spine #orthopedics @MedTweetorials @StefanTigges Image
2/A is for alignment. Normal spinal alignment is perfectly in balance, resulting in the minimal energy needed for erect posture. Even subtle changes in alignment need compensatory changes to maintain posture, resulting in more work/energy expenditure & pain. Image
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1/Don't fall for the siren song of calling all bright round objects at foramen of Monro colloid cysts. Like a true siren song, this may be a trap!
A🧵about lesions in this region that can trap you
#medtwitter #FOAMed #FOAMrad #medstudent #neurorad #radres #meded #Neurosurgery
2/Here are 3 lesions, all round and bright and in the region of the foramen of Monro. Can you tell from the images which is a colloid cyst and which may be something else? Choose which one or ones you think are a colloid cyst
Choose which one you think is a colloid cyst
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Sep 8
1/Controversy in radiology gets tense! The Mt Fuji sign for tension pneumocephalus is under scrutiny.When should you call it?
A #tweetorial about #imaging this important #neurosurgery complication
#medtwitter #FOAMed #FOAMrad #medstudent #neurorad #radres #meded #neurotwitter Image
2/Some believe that the peaked, mountain like appearance of the frontal lobes is a critical sign of a life-threatening complication & should be called & reported. Others believe it is too non-specific, is commonly seen when there isn’t tension & should be retired. Who’s right? Image
3/First, let’s clarify about what the Mt Fuji sign actually is. Most are familiar with the fact that large collections of pneumocephalus can compress the frontal lobes—making them look like the slopes of a mountain. But this isn’t actually enough to call Mt Fuji. Image
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Sep 6
1/Talk about going for the jugular! A 🧵 about a case I never thought I would never be lucky enough to see & the largest IJ I’ve ever come across!
#medtwitter #FOAMed #FOAMrad #medstudent #neurorad #radres #neurosurgery #meded #neurotwitter #radiology
2/A “syndromic appearing” young adult pt who was a poor historian & could not specify any prior diagnosis, p/w left neck swelling. On CTA, calling the IJ supersized would have been an understatement
3/Posterior to the IJ was a tangle of vessels, but no identifiable soft tissue mass, concerning for a vascular malformation. Catheter angiography showed a Jackson Pollack painting appearance of tangled vessels consistent with an AVM
Read 9 tweets
Sep 2
1/Feeling lucky? Or feeling evidence based?
A #tweetorial about how to read a #pituitary #MRI using data and know if there’s cavernous sinus invasion w/the Knosp score.
#medtwitter #FOAMed #radres #neurorad #FOAMrad #neurosurgery #medicalstudent #meded #USMLE #endocrinology Image
2/The hardest part of a pituitary MRI is deciding if there is cavernous sinus invasion. It makes sense that the more lateral a tumor goes on MRI, the more likely it has invaded the sinus—bc it is going the direction of the sinus. But how far is far enough? Image
3/This is important bc each time a radiologist makes a call on imaging, they make a bet & they are betting their credibility. And unlike other bets, there is only 1 wager—all in! So it is important to not call it when you might be wrong, bc overcalls destroy credibility. Image
Read 15 tweets

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