•Brain imaging
Often pursued to assess for a central process causing neurological changes
•Special Note: Your history and exam will be very important in order to get your brain imaging approved by insurance. If a patient reports “some memory concerns” and “diffuse weakness” but they have a normal neuro exam, and you didn’t get a mental assessment, there will be delays and extra steps in getting your imaging.
Always get a detailed history and complete a thorough exam!
•Brain imaging
Normal Brain MRI
Radiology Report:
No abnormal signal intensity of brain parenchyma. The white and grey matter differentiation are normal. No restricted diffusion. No hydrocephalus.
Stroke
ProTip: For any stroke, always define if it is ischemic or hemorrhagic (treatment for each varies greatly).
•Stroke…? or something else?
•Notice multiple lesions. A stroke diagnosis would be appropriate… but this would require multiple blockages, in different parts of the brain, all at the same time.
Hard to do
(“Like hitting a potato with a hammer and getting French Fries – it’s possible, but really hard to do”)
•The important thing is to look for an additional reason to cause this finding
A.fib with emboli
A PFO (clot from the leg broke off and went from right-sided circulation to left-sided circulation)
Note: Still hard to do. Usually requires concomitant “event” (cough/sneeze just as the clot was next to the PFO)
Septic emboli
Can consider if the patient has an infection. Usually requires a vegetation somewhere (classic is endocarditis), as a “ball of bacteria” needs to be knocked loose to cause the occlusion (regular bacteremia won’t do it).
•Hemorrhage
Subdural hematoma
Remember bleeding can occur around the brain. Here is a right-sided bleed with significant mass effect. This specific imaging shows an acute-on-chronic subdural hematoma. Notice how the blood has 2 densities (bright white and gray, with a clear fluid-fluid line). The gray is older, and frequently “settles” at the bottom of images.
•Mass effect
Mass effect can be seen as the pushing of the brain to one side.
We see shrinking of the ventricles and “midline shift”
You can actually calculate the midline shift
Drop a midline between the lobes (blue line)
Draw a horizontal line to the current midpoint between the ventricles (it’s shifted due to the bleed, so it’ll either be right or left of your midline). (red line)
The software can measure the length of that red line
•Brain Mass
Brain masses may be found on imaging
It’s important to remember that a tumor may be primary (the cells of that malignancy are consistent, and generated from, the tissue it is found in), or metastatic (the cells of that malignancy are different than the tissue it is found in).
Brain tumors are more likely to be from another source than to be a primary brain cancer.
Another “mass” to be mindful of in the brain, is an abscess.
Can be confused for malignancy
It’s unusual to have an abscess form in the brain and that needs further work-up
It can be difficult to definitively diagnose a brain mass (further work-up may be required).
•ProTip: If you ever see something on imaging (any imaging), and don’t know what it is, you can call it a “lesion.” Lesion is a non-descript word, but does identify that you found something.
•Brain Tumor
MRI ProTip: Check all the “views” (MRI’s will have many; these are compiled by the MRI software) – an abnormality (if present) usually lights up on one of them. The image below is the same study, at the same level, just under a different view (note that the tumor is way easier to appreciate on one compared to the other)
