Lea Alhilali, MD
Lea Alhilali, MD

@teachplaygrub

19 Tweets 5 reads Nov 20, 2024
1/Time to rupture all your misconceptions about aneurysms!
When you see an aneurysm on imaging, do you know if it’s at high risk of rupture?
This month’s @theAJNR SCANtastic shows you which aneurysms are bursting w/risk!
ajnr.org x.com
2/Aneurysm rupture is a devastating even, as it results in subarachnoid hemorrhage & complications such as hydrocephalus, vasospasm, infarcts, & death.
Preventing it by treating aneurysms before they rupture is key. But you also don’t want to overtreat. x.com
3/To remember what features make an aneurysm more likely to rupture, think what makes that guy at the bar that you angered more likely to rupture & start a fight.
What makes him more likely to rupture are the same things that make aneurysms more likely to rupture x.com
4/First is size. If he’s a big guy, he’s more likely to be willing to start a fight with you b/c he knows he’s more likely to win.
So big guys are more likely to rupture and start a fight. Same w/ aneurysms x.com
5/The larger the aneurysm measured by its maximum diameter (Dmax), the more likely it is to rupture.
Bigger aneurysms are more likely to rupture. So what size is concerning? x.com
6/A good rule of thumb is that aneurysms larger than 7mm are more likely to rupture.
You can remember this b/c rolling a lucky 7 in Vegas makes you rupture w/excitement
It’s not a guarantee & smaller aneurysms can still rupture. It truly is kind of like a crap shoot. x.com
7/Next is location
If you make the guy mad out back in the alley behind the bar, he’s more likely to rupture & start a fight than if you were in a crowded room
Same w/aneurysms—aneurysms in the back alley are more likely to rupture x.com
8/Aneurysms at the posterior communicating artery & in the posterior circulation are more likely to rupture
So remember, if it’s heading towards the back alley or if it’s in the back alley—it’s more likely that things are going to rupture x.com
9/Next is daughters
Nothing is more likely to get a guy to start a fight than messing w/his daughter
Same w/aneurysms. Aneurysms w/ “daughter” aneurysms or blebs are more likely to rupture. x.com
10/So for every aneurysm it is incredibly important to mention irregularity or “daughter aneurysms” or blebs
These significantly increase the risk of rupture, just like getting a guy’s daughter involved significantly increases the likelihood he is going to start something x.com
11/Finally, is the guy growing more angry?
If he is only getting more upset, this increases the likelihood that this isn’t going to end well for you
Same w/aneurysms. If they’re growing, they’re at increased risk of rupture x.com
12/For any aneurysm followed on serial imaging, growth of the aneurysm defined, as growth by >1 mm in any diameter, increases the risk of rupture
So don’t just gestalt it and say “basically unchanged” on follow-up studies for aneurysms! Small changes do matter. x.com
13/Other features are associated w/aneurysm rupture—but these 4 have the strongest evidence
Also clinical features increase risk of rupture, but this data isn’t always available. x.com
14/In this month’s @theAJNR, van Tuijl et al. used 4D MRA flow measurements to investigate why these imaging findings indicate high rupture risk
They found that high-risk imaging features are just surrogate markers of decreased aneurysm wall shear stress x.com
15/Why is low shear stress bad?
It’s bc wall shear stress is a scrubber for the aneurysm wall
It scrubs away thrombus, plaque, & inflammatory cells/molecules that weaken the aneurysm wall & increase risk of rupture x.com
16/Bigger size causes lower shear stress
It’s like a party. Small space means everyone is crushed together & has the same experience
Bigger space means people can go & have low stress separate conversations
Same w/aneurysms—more room = space for separate low stress vortices x.com
17/Daughter aneurysms also mean lower shear stress
A daughter aneurysm or bleb is like adding a separate room—that people can go away to have private conversations
This increases heterogeneity & low stress vortices x.com
18/Posterior aneurysms also have lower shear stress
Straighter morphology of the posterior circulation results in blood flow that looks like a fountain spout—organized & fast in the middle, but disorganized & slow on the outside
This causes lower shear stress x.com
19/Now you know the imaging features for rupture risk—and the shear stress physiology behind them
Now you shouldn’t be stressed when it comes to identifying high aneurysms!
This only scratches the surface. Follow @theAJNR & check it out for yourself:
ajnr.org x.com

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