Introduction to Neuroradiology

Question 1

What is fluoroscopy?

Answer 1

It is real time XR. Allows for adjustments if needed.
Uses contrast.
Includes swallowing studies, angiography, myelography.

Question 2

What does barium swallow eval?

Answer 2

Dysphagia
Epigastric pain
GERD

Sort of replaced by endoscopy.

Question 3

What does digital subtraction angiology refer to?

Answer 3

Angiography

Question 4

How is angiography performed?

Answer 4

An image is taken before to “subtract” bones and tissues after contrast is given.
It is fairly invasine as a catheter is needed.

Question 5

What is myelography?

Answer 5

Used to visualize the SC.
Requires a lumbar or cervical puncture with contrast.
F/U CT needed to eval contrast.

Question 6

What do you use for carotid stenosis?

Answer 6

Ultrasound

Question 7

What do you use to visualize fontanelles?

Answer 7

Ultrasound

Question 8

What do Hounsfield units measure?

Answer 8

Radiodensity in a CT (water is 0 HU)

Question 9

Hyperdense

Hypodense

Answer 9

Hyper: white/bright

Hypo: black/dark

Question 10

Wider windows of HU compare what?

Answer 10

Tissues of greater difference in HU (i.e. bone and air)

Question 11

Narrow windows of HU compare what?

Answer 11

Tissues of similar HU (i.e. brain and blood)

Question 12

What is the window?

What is the level?

Answer 12

Window is range of HU.

Level is middle of window.

Question 13

What does CT have low sensitivity to?

Answer 13

Posterior fossa

Question 14

What is CT used for in the brain?

Answer 14

Skull, vertebrae.
Ventricles (hydocephalus, masses)
Hemorrhage, ischemia
Calcification (lesion characterization)

Question 15

When is non-contrast CT used?q

Answer 15

In pts w/ head/spine trauma and acute stroke.

It is the preferred study within 3 hrs of acute onset.

Question 16

When is contrast used?

Answer 16

When sx last more than 3 hrs.

Question 17

No contrast:

Answer 17

Trauma
R/O hemorrhage
Hydrocephalus
Dementia
Epilepsy

Question 18

Yes contrast:

Answer 18

Neoplasm
Infection
Vascular dz
Inflammatory dz

Question 19

What is the risk of MRI contrast in a patients with renal insufficiency?

Answer 19

Nephrogenic systemic fibrosis

Question 20

What does it mean when a tissue “enhances”?

What does it reflect?

Answer 20

Gets brighter with contrast.

Reflects the vascularity of the tissue.

Question 21

What structures will enhance w/ IV contrast (outside of BBB)?

Answer 21

Cerebral BVs
Meninges
Pineal gland
Pituitary
Choroid plexus

Question 22

How are contrast studies and angiograms different?

Answer 22

Contrast is used to eval where the breakdown is in the vessls in the BBB, while angiograms are used to visualize the BVs.

Question 23

MRI

Hyperintense
Hypointense

Answer 23

Hyperintense: white/bright
Hypointense: black/dark

Question 24

What is MR used for in the head?

Answer 24

Eval ischemia, chronic/subacute sx, tumors, infection.

Question 25

T1

Answer 25

CSF is dark (hypointense)

White matter is bright (hyperintense)

Question 26

T2

Answer 26

CSF is bright (hyperintense)

White matter is dark (hypointense)

Question 27

T2 FLAIR

Answer 27

Removes CSF from T2 image.
Good for eval edema/abscesses (high protein content)
Dying neurons stop Na/K pumps and water accumulates = edema.