14. Imaging of Head and Neck (Fellow)

Question 1

What is MRI contrast made of?

What are the possible complications?

Answer 1

Gadolinium.

Nephrogenic systemic fibrosis in pts with renal insufficiency.

Question 2

What are the three types of flouroscopy discussed?

Answer 2

Barium Swallow

Angiography

Myelography

Question 3

What is bright and dark in a T2 MRI?

Answer 3

T2 = CSF is bright, white matter is dark.

(T2 = too bright)

Question 4

What is a T2 FLAIR good for?

Answer 4

Visualizing edema.

(FLuid Attenuated Inversion Recovery)

Question 5

What is bright and dark in T1 MRI?

What is it good for?

Answer 5

T1 = CSF is dark, white matter is light.

Good for anatomy.

Question 6

How would you want to set up your CT to look at bone?

Answer 6

Large window, high level.

W:1000 HU L: 400

Question 7

When would an MRI be preferable to a contrast CT?

Answer 7

If blood (and therefore contrast) cannot get to the area - such as in ischemic areas..

Question 8

How might you want to set up your CT to evaluate soft tissue?

Answer 8

You will want a narrow window (eg: 90 HU window) with a level (center of the window) of 50.

Soft tissue = W: 90HU L: 50HU

Question 9

Why might one prefer a CT angiography over a fluoroscopy angiography?

Why might one prefer fluoroscopy?

Answer 9

CT angiography is not invasive, because — unlike fluoroscopic angiography — you don’t have to inject contrast directly into the artery. In CT angiography the contrast is administered via an IV bolus.

Also in CT angiography, you can evaluate blood vessels from the heart to the point of interest, unlike fluoroscopic angiography - which is more distal.

All that said, fluoroscopy angiography has a higher resolution.

Question 10

When is contrast indicated for a CT, and when is it not indicated?

Answer 10

• Contrast indicated:
  
  • Neoplasm
  • Infection
  • Vascular disease
  • Inflammatory disease
• No contrast
  
  • Trauma
  • To rule out hemorrhage
  • Hydrocephalus
  • Dementia
  • Epilepsy

Question 11

What is CT contrast made of?

What are possible complications?

Answer 11

Iodine (based).

Anaphylaxis.

Question 12

X-rays work by:

Indications for X-Ray

Answer 12

different tissues produce sudden deccelerations of electons on anodes (gas, fat, water, minera)

use for trauma, degenerative diseases (RA), post-operatively

Question 13

Angiography

indications:

pros:

cons:

Answer 13

anuerysm, vascular malformtation, fistula, stenosis, thrombosis, stenting

P: fast, diagnostic and therapeutic

C: invasive, contrast, radiation

Question 14

Myelography

Indications:

Pros:

Cons:

Answer 14

spinal stenosis, nerve root compression, CSF leak

P: defines SA space, identify spinal block

C: invasive, spinal headache/CSF leak, radiation, contrast

Question 15

CT

Indications

Pros:

Cons:

Answer 15

trauma, ventriculat anatomy, IC mass, CVA/TIA, calcifcation

P: fast, cheap, good for large pathology

C: less detail than MRI, radiation, low sens. in posterior fossa

Question 16

When will you see contrast in the brain parenchyma?

Structures enhanced with contrast outside BBB?

Answer 16

if there is an absence of the blood brain barrier

cerebral blood vessels, meninges, pineal gland, pit. gland, choroid plexus

Question 17

CT Angiography

Indications

Pros

Cons

Answer 17

atherosclerosis, dissection, aneurysm, trauma

P: non-invasive, see origin

C: contrast, radiation, lower res.

Question 18

US

Indications

Pros:

cons:

Answer 18

carotid arteries, central line placement, tough IV placement

P: non-invasive, cheap, no radiation

C: hard to learn