Lec 22: Neuroimaging of the Brain and Skull Flashcards Preview

[OS 211] Neuro Exam 1 Flo Cluster > Lec 22: Neuroimaging of the Brain and Skull > Flashcards

Flashcards in Lec 22: Neuroimaging of the Brain and Skull Deck (29)
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1
Q

The golden period for stroke patients.

A

3-4 hours

2
Q

True or False: In CT, gray matter is whiter than white matter.

A

TRUE.

3
Q

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

A

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.
4
Q

The primary modality of choice in acute trauma to the brain and spine, suspected subarachnoid hemorrhage and conductive hearing loss.

A

CT Scan

5
Q

TRUE or FALSE: For early hemorrhages, CT is more accurate than MRI.

A

TRUE. It takes 6-12 hours before an MRI can detect hemorrhage

6
Q

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.

A

TRUE. But after 12 hours, specificity and sensitivity are equal.

7
Q

Imaging modality of choice for acute stroke.

A

MRI

8
Q

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

A

b. T2-weighted MRI

Pnemonic: WW2 - “Water is White in T2”

9
Q

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.

A

Diffusion Weighted Imaging

10
Q

Can be paired with Diffusion Weighted Imaging to further classify infarcts into acute, subacute or chronic.

A

Attenuated Diffusion Coefficient (ADC) Map

  • A hypointense (dark area} represents a hyperacute infarct. Lighter ones means more chronic
11
Q

Used for the detection of hemorrhage/ bleed and produces images with clear areas of hypo/hyper intensity and measurable size.

A

Gradient Recalled Echo Image

12
Q

What imaging modality should you request that can visualize infarcted areas the best?

A

Diffusion Weighted Imaging

13
Q

TRUE or FALSE: If suspecting a new stroke, MRI should be used.

A

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.

14
Q

An area of markedly reduced perfusion with loss of function of still viable (salvageable) neurons

A

Penumbra

15
Q

An imaging modality used for evaluation of blood flow to a specific region of the brain.

A

Perfusion Imaging

16
Q

Therapeutic window for reperfusion of brain tissue.

A

3-6 hours.

*can be increased up to 10 hours if vampire bat venom (anticoagulant) is given.

17
Q

TRUE or FALSE: A hypoperfused area of the brain can still be salvaged if there is a matched diffusion-perfusion.

A

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.

18
Q

Beyond this size, the aneurysm is considered to be HIGH RISK.

A

> 10mm

19
Q

TRUE or FALSE: Subdural hemorrhage may cross suture lines, dural attachments and tentorial reflections.

A

FALSE. Subdural hemorrhage can cross suture lines only, not dural attachments or tentorial reflections.

20
Q

The most sensitive modality for subdural hemorrhage.

A

FLAIR T2

*Fluid-Attenuated Inversion Recovery

21
Q

TRUE or FALSE: FLAIR images are more sensitive than standard spine echo images for the detection of lesions within or adjacent to CSF.

A

TRUE.

22
Q

Most common cause of subarachnoid hemorrhage aside from trauma.

A

berry aneurysms

23
Q

Gray-white matter interface is no longer discernible

a. Diffuse axonal injury
b. Cerebral contusion
c. Arachnoid cyst
d. Lymphoma

A

a. Diffuse axonal injury

24
Q

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

A

d. subarachnoid space

25
Q

TRUE or FALSE: For Glioblastoma multiforme, the more heterogeneous-looking the tumor is, the better the prognosis.

A

FALE. If more hetergeneous-looking, worse prognosis.

26
Q

Pathognomonic of a meningioma

A

dural tail

27
Q

Anteroposterior elongation of the cranium.

a. brachycephaly
b. scaphocephaly
c. plagiocephaly
d. turricephaly

A

b. scaphocephaly (sagittal synostosis)
- brachycephaly - diminished anteroposterior skull
- plagiocephaly - sutural assymetry, right-sided harlequin eye
- turricephaly - fusion of multiple sutures, weirdly shaped head

28
Q

TRUE or FALSE: A cyclops baby can live if the holoprosencephaly is lobar.

A

TRUE.

29
Q

A condition wherein the brain has no sulci and the patient can be severely mentally retarded.

A

Lissencephaly