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
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.
3/The goals for alignment on imaging: (1) look for unstable injuries & (2) look for 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
4/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.
5/Assess the ligaments w/the bones. Unlike long bones, ligaments in the spine cover along the bones like saran wrap. Anterior longitudinal along the vertebral body front, posterior longitudinal along the vertebral body & posterior ligamentous complex along posterior elements
6/On CT, you can infer ligamentous injury from the alignment—if the space is too wide, the ligament can’t be intact. On MR you can see edema in the ligament (suspect ligamentous injury) or focal disruption (see the ligamentous injury)
7/C is for canal on CT & cord on MRI. On CT, look at canal contents for any large masses or collections that could compromise the canal. You won’t see it all, but you have to try. On MR, assessing the canal is easy. You can also see the cord itself to check for edema/injury
8/D is for discs or degenerative findings. Normal discs should look like a kidney on its side, with a little indentation in the middle just like the renal hilum. Any change to this reniform shape means that there is a disc bulge.
9/Normal discs also have a very distinctive appearance on sagittal imaging. You should see a T2 bright disc with a dark nucleus pulposus center. It looks like the cross section of a jelly filled donut
10/If you lose that jelly filled donut appearance, and the discs look flatter or darker without a definable center—more like flat pancakes than jelly donuts—then the disc is degenerated.
11/Several things can happen to a degenerated disc. First, you can get a bulge. I think of a bulge like gaining weight—you slowly get fatter & loosen your belt. For a disc, the annulus degenerates, gets looser & the disc gets a pot belly—so you lose the renal hilum indentation.
12/Next you can get a protrusion. If a bulge is loosening your belt (i.e., the annulus is more lax but still intact), a protrusion is like a hernia. The annulus suddenly tears and disc herniates out. This means it is more focal and can happen more acutely.
13/Next is an extrusion. Extrusion is when herniated disc become like toothpaste. B/c it’s squishy like toothpaste, an extrusion can move up or down away from the parent disc. Extrusion base can be smaller than the rest of it bc it can squish through small holes like toothpaste
14/Finally is a free fragment. This is when a piece of the extrusion breaks off from the rest of the disc—like when you break off some toothpaste onto your toothbrush. You can see this on imaging bc the fragment is usually a different signal than the parent disc—much T2 brighter
15/Besides the disc, you should also look at the facet joints. A normal facet joint looks like a hamburger. When the facet starts to look more like a mushroom than a hamburger, with overhanging osteophytes, that’s when I call it degenerated
16/In the c-spine, there are also uncovertebral joints. These are at the lateral vertebral body. Normally they should be smooth. On coronal images, they look like little devil horns. When they start to get osteophytes & look more like moose antlers, then they are degenerated.
17/So every spine dictation becomes formulaic, like a mad libs fill in the blank. Go through your ABCs and look for abnormalities in each. When you get to the D, if the study was done for degenerative changes, you should evaluate each level individually.
18/At each level, it is also a fill in the blank formulaic dictation. You should assess disc, facets, & possibly uncovertebral joints, looking for the signs we have talked about that show they are degenerated. Then you should say what they are doing to the canal & neural foramina
19/So now you know how to approach spine imaging studies in a systematic way—so that your dictations will have all the necessary elements to strike that perfect balance between enough detail and enough brevity. I told you I had your back!
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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