2/Older pt w/lower extremity numbness. MRI showed intradural, extra-axial rounded lesions in the lower thoracic region that avidly enhanced on post-contrast imaging—like gang busters enhancement
3/On the T2 weighted images, the lesions showed a very distinct donut-like appearance, with a very dark, almost black rim and a bright center.
4/On contrast imaging, the donuts were connected as twisty, tubular structures—my fellow said they looked like crinkle fries! (and yes, I know McDonald’s doesn’t serve crinkle fries as illustrated, but it’s just an illustration—there aren’t fries in the spine either 😉)
5/Tubular sounds like a vessel! And these did empty out into the neural foramina. But the spinal angio was negative for a vascular lesion (not all images shown—normal studies don’t make for good twitter images)
6/These are intradural varices! B/c of slow flow, they may not fill on angiography & lose their flow void centrally—causing a“donut sign.” Etiology is unclear, but likely acquired
So the next time you see donuts & fries in the spine—you can be sure you've got the right diagnosis
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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 & let RAPID read the perfusion for you? Not anymore!
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.
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.
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
1/”I LOVE spinal cord syndromes!” is a phrase that has NEVER, EVER been said by anyone.
Do you become paralyzed when you see cord signal abnormality?
Never fear—here is a thread on all the incomplete spinal cord syndromes to get you moving again!
2/Spinal cord anatomy can be complex. On imaging, we can see the ant & post nerve roots. We can also see the gray & white matter. Hidden w/in the white matter, however, are numerous efferent & afferent tracts—enough to make your head spin.
3/Lucky for you, for the incomplete cord syndromes, all you need to know is gray matter & 3 main tracts. Anterolaterally, spinothalamic tract (pain & temp). Posteriorly, dorsal columns (vibration, proprioception, & light touch), & next to it, corticospinal tracts—providing motor