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
4/So let’s start w/the oldest part of the temporal lobe, the hippocampus, and we will move clockwise from there.
5/Next to the hippocampus is the parahippocampal gyrus. I remember this b/c the hippocampus is the oldest part of the temporal lobe & older folks love to go in pairs. So this is the PAIR-ahippocampal gyrus—it pairs w/the old hippocampus
6/Next to the parahippocampal gyrus is the fusiform gyrus. I remember this b/c this gyrus bridges (some might say FUSES) the older, allocortex part of the temporal lobe (hippocampus/parahippocampal) w/the newer, neocortical structures. Fusiform gyrus is the neocortical bridge
7/Fusiform gyrus bridges the older temporal lobe w/the new lateral temporal neocortex.
I think the lateral neocortex looks like a parfait—w/the superior, middle, & inferior temporal gyri layered on top of the fusiform gyrus. Heschl’s transverse gyrus forms the strawberry on top
8/You can remember that the fusiform gyrus is at the bottom of this parfait b/c fusiform means elongated—and the stem of a parfait glass is elongated—almost fusiform!
9/You can remember that Heschl’s gyrus is the fruit on top b/c Heschl sounds like Bushel, and fruit to put on top comes in Bushels!
10/You can also see this parfait in the coronal plane, although it is a little tilted!
11/Last temporal lobe structure is the temporal stem. It is the white matter connecting the gyri of the temporal lobe to the rest of the brain. I remember this b/c I think the temporal lobe looks like an upside-down cauliflower—& the STEM of that cauliflower is the temporal STEM
12/So now you can remember the anatomy of the temporal lobe:
An old couple
A bridge fusing them to the next generation
A delicious parfait
All connected by a cauliflower stem.
I hope this new anatomy knowledge will be anything but temporary!
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Brain MRI anatomy is best understood in terms of both form & function.
Here’s a short thread to help you to remember important functional brain anatomy--so you truly can clinically correlate!
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)
@TheAJNR 2/Everyone knows about the spot sign for intracranial hemorrhage
It’s when arterial contrast is seen within a hematoma on CTA, indicating active
extravasation of contrast into the hematoma.
But what if you want to know before the CTA?
@TheAJNR 3/Turns out there are non-contrast head CT signs that a hematoma may expand that perform similarly to the spot sign—and together can be very accurate.
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.