Neuro-Imaging

Question 1

Types of neuroimaging:

Answer 1

1. CT
2. MRI
3. Cerebral angiography (MRA and CT angiography)

Question 2

Which neuroimaging allows for in vivo visualization of orbits and intracranial contents:

Answer 2

CT and MRI

Question 3

___ allows for clinicians to better view intracranial vasculatures.

Answer 3

Cerebral angiogrpahy (MRA and CT angio)

Question 4

CT utilizes ___ and ___ based technology that images ___ objects as ___

Answer 4

X-ray; computer; 3D; slices

Question 5

What is a limitation of CT? and name an example.

Answer 5

High attenuation of x-rays by bone (tissues within bone will have less detail)

Ex. skull base (post fossa and brainstem) > MRI preferable

Question 6

CT: hypodensity is ___ and hyperdensity is ___. (CT = sity)

Answer 6

Dark; bright

Question 7

CT, x-ray, and MRI: pts OD in on the ___ side.

Answer 7

Left

Question 8

MRI has magnetic field gradient which forces protons in ___ to align.

Answer 8

H atoms

Question 9

T/F: In MRI, radio frequency (RF) pulse disturbs the magnetically induced alignment.

Answer 9

T

Question 10

Parameters of RF pulse:

Answer 10

Time echo (TE) 
Repetition time (TR)

Question 11

___ IV contrast enhances vascular structures, BBB, and lesions.

Answer 11

Gadolinium

Question 12

MRI types:

Answer 12

T1 weighted (longitudinal)
T2 weighted (transverse)

Question 13

T1 and T2 deals w ___, magnetization, and spin of ___.

Answer 13

Phasing; photons

Question 14

In T1, TE and TR are set to ___ times.

Answer 14

Short

Question 15

In T2, TE and TR are set to ___ times.

Answer 15

Long

Question 16

T1 has exquisite detail and ___.

Answer 16

Anatomy

Question 17

T2 emphasizes ___.

Answer 17

Pathological lesions

Question 18

In T1, CSF and vitreous are dark or ___ signal intensity. (Hint: MRI = Intensity)

Answer 18

Low

Question 19

In T2, CSF and vitreous are ___ or high signal ___.

Answer 19

Bright; intensity

Question 20

MRI contraindications:

Answer 20

• Any electrically, magnetically, or mechanically activated (ex. hearing aids, insulin pump)
• Metal
• Intracranial aneurysm clips (unless made of titanium)
• Pregnancy

Question 21

Indications for neuroimaging (orbit):

Answer 21

• VA loss (intracranial, pre/post chiasmal)
• Vascular lesions of orbit
• Hx of visual disturbances
• Optic nerve sheath meningioma
• Optic nerve neuritis
• Optic nerve glioma
• Tumors
• Unilateral proptosis
• Orbital abscess (pus)
• Inflammation
• Thyroid ophthalmopathy
• Extraocular myopathy

Question 22

CT: ___ is bright due to high attenuation.

Answer 22

Bone

Question 23

CT: Orbital fat and air sinuses appear dark due to ___ attenuation.

Answer 23

Least

Question 24

CT: ___, ___, ___ have intermediate attenuation.

Answer 24

EOM, blood vessels, ON = GOOD

Question 25

___ are the go to for CT.

Answer 25

Brain hemorrhages

Question 26

MRI: Orbital fat is very ___ and obscures anatomical detail.

Answer 26

Bright

Question 27

MRI: ___ suppression allows for better orbital detail.

Answer 27

Fat

Question 28

___ > ___ if brain needs to be imaged.

Answer 28

MRI > CT

Question 29

___ is better at imaging bone (ex. bone fractures).

Answer 29

CT

Question 30

Both CT and MRI may be needed to characterize an ___ lesion.

Answer 30

Orbital

Question 31

___ slices (3 mm apart) offers best orientation for orbit contents.

Always specify thin slices and coronal views for orbital imaging.

Answer 31

Coronal

Question 32

Advantages of imaging brain w MRI:

1. MRI better at imaging the ___ and ___ due to bone attenuation w CT.
2. MRI distinguishes ___ and ___ matter w more resolution.
3. MRI ___ are more equal.
4. MRI can detect cortical ___ within hours.
5. Image of choice for ___, MS, ___

Answer 32

1. Post fossa and sella turcica
2. White and gray
3. Planes
4. Infarcts
5. Tumor, MS, and ischemic stroke

Question 33

Disadvantage of MRI:

Answer 33

CT is cheaper, faster, less claustrophobic

Question 34

Pathological processes normally increase water content in tissue which results in a signal increase in ___, ___, and ___.

Answer 34

FLAIR, STIR, DWI

Question 35

Pathological processes are usually ___ and useful w FLAIR, STIR and DWI imaging techniques.

Answer 35

Brighter

Question 36

T1 useful in differentiating brain’s ___, brain appears ___ gray, ___ has high intensity and ___ contrast can light up a tumor or abscess.

Answer 36

Parenchyma; medium; fat; gadolinium

Question 37

In T2, brain appears ___ gray, edema are ___ spots, and useful for ___ pts.

Answer 37

Light; bright; MS

Question 38

___ are sensitive to ___ and ___ abnormalities and useful for monitoring and detecting low grade ___.

Answer 38

FLAIR; edema and parenchymal; gliomas

Question 39

___ helpful in confirming ishemic event.

Answer 39

DWI

Question 40

___ used to image cerebral vasculature (aneurysms, vasculitis)

Answer 40

Cerebral angiography

Question 41

Four vessel cerebral ___, MRA, CT ___.

Answer 41

Angiogram, angiography