Week 3

Question 1

what three things should an otologist provide to the neuroradiologist when ordering imaging?

Answer 1

• working diagnosis (what do we know so far)
• differential diagnosis
• desired imaging modality

Question 2

3 imaging options

Answer 2

• CT
• MRI
• MRA

Question 3

what does CT stand for?

Answer 3

computed tomography

Question 4

What does MRI stand for?

Answer 4

magnetic resonance imaging

Question 5

what does MRA stand for

Answer 5

magnetic resonance angiography

Question 6

how does CT work

Answer 6

beam of x-rays pass through the pt in slices

*good for bony areas

Question 7

CT cons

Answer 7

• difficult to differentiate b/t soft tissue with similar densities
• contrast CT may be lethal to some pts due to anaphylaxis and renal impairment

Question 8

CT pros

Answer 8

• very short test

* excellent imaging of bony structures

Question 9

how does MRI work

Answer 9

• uses powerful magnetic field and radio waves to produce cross sectional images
• can do multiple planes without moving pt
• ideal for differentiating tissue
• contrast is frequently used with safety

Question 10

pros of MRI

Answer 10

• great for finding tumors and plaque from MS

* can find v small tumors

Question 11

cons of MRI

Answer 11

• no metal
• take long time (30-60 minutes)
• v loud (95 dB)
• claustrophobia

Question 12

how does MRA work

Answer 12

• provides info on vertebrobasilar arterial system with puncture of the femoral artery (arterial venipuncture) that delivers iodinated contrast through arteries
• small risk of stroke
• hematoma at puncture site
• not often ordered because invasive and CT and MRI are often effective enough to find lesion