The golden period for stroke patients.
3-4 hours
True or False: In CT, gray matter is whiter than white matter.
TRUE.
The following changes can indicate an ischemic stroke, EXCEPT:
a. Poor definition of gray-white matter interface
b. Obscuration of lentiform nucleus
c. Effacement of sulci because of edema
d. Presence of hyperattenuating/hyperdense arteries.
e. NOTA
e. NOTA
The other choices are subtle changes that occur when there’s a blockage in certain areas.
- Poor definition of gray and white matter can be an indication of an hyperacute infarct.
- Hyperdense arteries can indicate the presence of a thrombus, calcifications or slow flow of blood.
The primary modality of choice in acute trauma to the brain and spine, suspected subarachnoid hemorrhage and conductive hearing loss.
CT Scan
TRUE or FALSE: For early hemorrhages, CT is more accurate than MRI.
TRUE. It takes 6-12 hours before an MRI can detect hemorrhage
TRUE or FALSE: Conventional MRI is more sensitive and specific than CT for detection of cerebral ischemia during the first few hours after symptom onset.
TRUE. But after 12 hours, specificity and sensitivity are equal.
Imaging modality of choice for acute stroke.
MRI
You see that the cerebrospinal fluid is white within the ventricles. The imaging modality used was:
a. T1-weighted MRI
b. T2-weighted MRI
c. either
d. neither
b. T2-weighted MRI
Pnemonic: WW2 - “Water is White in T2”
A very sensitive imaging modality for acute and hyperacute stroke which can enable differentiation between various differentials and can see the infarct better than a T2-weighted MRI.
Diffusion Weighted Imaging
Can be paired with Diffusion Weighted Imaging to further classify infarcts into acute, subacute or chronic.
Attenuated Diffusion Coefficient (ADC) Map
- A hypointense (dark area} represents a hyperacute infarct. Lighter ones means more chronic
Used for the detection of hemorrhage/ bleed and produces images with clear areas of hypo/hyper intensity and measurable size.
Gradient Recalled Echo Image
What imaging modality should you request that can visualize infarcted areas the best?
Diffusion Weighted Imaging
TRUE or FALSE: If suspecting a new stroke, MRI should be used.
TRUE. MRI is better than CT at identifying acute ischemic changes. After 12 hours, you can request for a CT scan instead because the sensitivity becomes similar to when using MRI and 3-4x cheaper.
An area of markedly reduced perfusion with loss of function of still viable (salvageable) neurons
Penumbra
An imaging modality used for evaluation of blood flow to a specific region of the brain.
Perfusion Imaging
Therapeutic window for reperfusion of brain tissue.
3-6 hours.
*can be increased up to 10 hours if vampire bat venom (anticoagulant) is given.
TRUE or FALSE: A hypoperfused area of the brain can still be salvaged if there is a matched diffusion-perfusion.
FALSE. The bigger the MISMATCH, the greater the chance that the hypoperfused area of the brain can still be salvaged.
*If the DWI showed a relatively smaller infarct compared to the hypoperfused area in the perfusion imaging, it has a higher chance to be salvaged.
Beyond this size, the aneurysm is considered to be HIGH RISK.
> 10mm
TRUE or FALSE: Subdural hemorrhage may cross suture lines, dural attachments and tentorial reflections.
FALSE. Subdural hemorrhage can cross suture lines only, not dural attachments or tentorial reflections.
The most sensitive modality for subdural hemorrhage.
FLAIR T2
*Fluid-Attenuated Inversion Recovery
TRUE or FALSE: FLAIR images are more sensitive than standard spine echo images for the detection of lesions within or adjacent to CSF.
TRUE.
Most common cause of subarachnoid hemorrhage aside from trauma.
berry aneurysms
Gray-white matter interface is no longer discernible
a. Diffuse axonal injury
b. Cerebral contusion
c. Arachnoid cyst
d. Lymphoma
a. Diffuse axonal injury
Diffuse axonal injury tends to occur in these fundamental anatomic areas, EXCEPT:
a. lobar white matter
b. corpus callosum
c. dorsolateral aspect of brainstem
d. subarachnoid space
d. subarachnoid space
TRUE or FALSE: For Glioblastoma multiforme, the more heterogeneous-looking the tumor is, the better the prognosis.
FALE. If more hetergeneous-looking, worse prognosis.
Pathognomonic of a meningioma
dural tail
Anteroposterior elongation of the cranium.
a. brachycephaly
b. scaphocephaly
c. plagiocephaly
d. turricephaly
b. scaphocephaly (sagittal synostosis)
- brachycephaly - diminished anteroposterior skull
- plagiocephaly - sutural assymetry, right-sided harlequin eye
- turricephaly - fusion of multiple sutures, weirdly shaped head
TRUE or FALSE: A cyclops baby can live if the holoprosencephaly is lobar.
TRUE.
A condition wherein the brain has no sulci and the patient can be severely mentally retarded.
Lissencephaly
