2/ASPECTS stands for “Alberta Stroke Program Early CT Score.” It is meant to replace gestalt-ing what percent of the MCA territory is infarcted. Instead, it uses a 10-pt score to semi-quantitate the amount of infarcted tissue in the MCA territory on non-contrast head CT
3/You can think of it as a scorecard for the MCA.
For each region of MCA territory NOT infarcted, the pt gets one point
So the highest score possible is 10, and lowest score possible is 0
4/To get this score, the system divides the MCA up into 10 different regions.
Think of it like a map of the MCA territory. Instead of one big territory, it divides it up into sections—like how the US is divided into states. 1 pt for each state that is NOT low density on CT
5/I think of it like a city. As long as power is flowing, the city is lit up with lights. Same w/the brain. As long as blood is flowing, it will be relatively brighter on CT
6/However, when power gets cut off to a certain sector of the city, it will go dark. Same w/the brain. When blood is cut off to a section of the MCA territory, it will literally go dark—be low density on CT.
7/The ASPECTS score basically subtracts a point for each sector of the brain in which the lights have gone out (low density). This tells you that this region is irreversibly infarcted. More regions that are low density, the bigger the blackout and more infarcted tissue.
8/A high ASPECTS score means all the lights are on. As more sectors go dark, the score decreases, until it is a total blackout, and the entire MCA territory is lost w/an ASPECTS of zero.
9/What are the sectors and how do you identify them? Well, you start at the level of the basal ganglia or “ganglionic” level. I always remember that this is the level to start at b/c it gives me a chuckle when I think of Canadian gangs.
10/At this level, you have 7 structures to decide if they are blacked out. You have the 3 structures of the basal ganglia/internal capsule medially, the insula in the middle, and the lower MCA cortex on the outside--separated into 3 sections.
11/I remember this by remembering that the insula is INSULAted—so it is sandwiched between the basal ganglia/internal capsule & MCA cortex. Everything comes in sets of 3 in ASPECTS, so you see 3 BG/IC structures on this ganglionic slice & you divide the cortex into 3 sections
12/You can remember the 3 MCA cortex sections by remembering that M1 is essentially Broca’s area. With Broca’s aphasia you can only get one word out at a time (kind of), so it’s M1. Wernicke’s rhymes w/three, so it’s M3. And then M2 is just in between.
13/Next sections are on the next slice up that is above the basal ganglia (supraganglionic). Rule of 3, so 3 sections are here. There aren’t any deep structures here, just MCA cortex. Each higher MCA section is directly above the lower MCA sections & numbered in the same order
14/I think that the finger-like gyri of these cortices stick out like french fries--which matches our burger from the ganglionic level
15/So all you have to remember is the rule of 3s & a burger & fries to remember ASPECTS
At the ganglionic level, the insula is in the middle of a burger between buns of 3 deep structures & 3 lower MCA cortices
Higher, there are 3 finger-like fries of the higher MCA cortices
16/ASPECTS is important for prognosis. Low ASPECTS scores have poorer prognosis, w/greater risk of disability, hemorrhage, and poorer outcome after treatment.
17/You can remember that ASPECTS below 7 and 8 are bad bc it used to be that 70% was the minimum to pass in grade school—below 70% was failing. And all those fun training modules the hospital makes you do—they require an 80% pass rate to move on. So < 7 or 8 conveys higher risk
18/So now you know the burger and fries of the ASPECTS score--a fitting meal for those hungry to learn about stroke imaging!
• • •
Missing some Tweet in this thread? You can try to
force a refresh
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
1/Do you get a Broca’s aphasia trying remember the location of Broca's area?
Does trying to remember inferior frontal gyrus anatomy leave you speechless?
Don't be at a loss for words when it comes to Broca's area
Here’s a 🧵to help you remember the anatomy of this key region!
2/Anatomy of the inferior frontal gyrus (IFG) is best seen on the sagittal images, where it looks like the McDonald’s arches.
So, to find this area on MR, I open the sagittal images & scroll until I see the arches. When it comes to this method of finding the IFG, i’m lovin it.
3/Inferior frontal gyrus also looks like a sideways 3, if you prefer. This 3 is helpful bc the inferior frontal gyrus has 3 parts—called pars
1/Need help reading spine imaging? I’ve got your back!
It’s as easy as ABC!
A thread about an easy mnemonic you can use on every single spine study you see to increase your speed & make sure you never miss a thing!
2/A is for alignment
Look for: (1) Unstable injuries
(2) Malalignment that causes early degenerative change. Abnormal motion causes spinal elements to abnormally move against each other, like grinding teeth wears down teeth—this wears down the spine
3/B is for bones.
On CT, the most important thing to look for w/bones is fractures. You may see focal bony lesions, but you may not
On MR, it is the opposite—you can see marrow lesions easily but you may or may not see edema associated w/fractures if the fracture is subtle