Imaging Of The Head And Neck

Question 1

How is an x ray produced?

What can you use it for?

What types are there?

Answer 1

Produced by sudden deceleration of electrons hitting anode with different tissues absorbing radiation differently

Use for trauma, degenerative disease, post op

PA, AP, lateral

Question 2

What is fluoroscopy?

When can you use this?

Answer 2

Continuous x ray radiation passing thru body onto a fluorescent screen creating a moving x ray image

Swallow study
Interventional radiology
Arthography
Cardiac catheterization

Question 3

What is an angiography?

What can is be used for?

Answer 3

Fluoroscopy with injection of contrast into vasculature intending to evaluate peripheral vasculature

Aneurysms, vascular malformation, fistulae, stenosis, thrombosis, dissection, stenting, thrombolysis

Contrast: barium or iodine

Question 4

What are the pros to angiography?

Cons?

Answer 4

Pros: fast, diagnostic and therapeutic

Cons: invasive, contrast, radiation

Question 5

What is myelography?

When can you use it?

Answer 5

Uses fluoroscopy
Intrathecal injection of contract

Spinal stenosis, nerve root compression, CSF leak

Question 6

What are the pros for myelography?

Cons?

Answer 6

Defines subarachnoid space
Identifies spinal block

Invasive
could cause CSF leak, headache
Uses radiation
Uses contrast

Question 7

What is computed tomography?

What is the radio density measured in?

Answer 7

Series of x-Rays scanned axially.

Hounsfield units

Question 8

What is the Hounsfield unit of water?

What will appear white? What will appear black?

Answer 8

0 HU

Hyper dense (>0) = white

Hypodense (<0) = black

Question 9

How are CTs read?

Answer 9

As if looking at the patient from the feet

Question 10

What is the HU of

Air
Bone
Water/CSF

Answer 10

Air: -1000

Bone: +1000

Water/CSF: 0

Question 11

What can CTs be used for?

Answer 11

Skull, skull base and vertebrae
Ventricles 
Intracranial masses, mass effect
Hemorrhage, ischemia
Calcification

Question 12

What are the pros to CTs?

Cons?

Answer 12

Pros: fast, relatively inexpensive, good at detecting large pathology

Cons: less detailed than MRI, radiation exposure, low sensitivity in posterior fossa

Question 13

When would contrast be indicated?

Answer 13

Neoplasm
Infection
Vascular disease
Inflammatory disease
More than 3 hours after onset of symptoms

Question 14

When would contrast be contraindicated?

Answer 14

Trauma
Hemorrhage
Hydrocephalus
Dementia
Epilepsy
Within 3 hours of symptoms

Question 15

What keeps IV contrast out of brain?

Answer 15

Blood brain barrier

Enhancement of brain parenchyma w/ contrast would indicate absent BBB or pathology

Question 16

What are structures that will enhance with IV contrast?

Answer 16

Cerebral blood vessel 
Meninges - dura, arachnoid, pia 
Pineal glands
Pituitary gland
Choroid plexus

Question 17

What would you use a CT angiography for?

Answer 17

Atherosclerosis, dissection, aneurysm, trauam

Question 18

What are the pros and cons to CT angiography?

Answer 18

Pros: non-invasive, examine vessels from origin

Cons: contrast, radiation, lower resolution

Question 19

What is MRI?

Hyperintense radiodensity will appear?
Hypo-intense radiodensity will appear?

Answer 19

Large magnet aligns all the protons in the body, then radio waves pass thru patient and returning signals are converted into an image

Hyper-intense: white
Hypo-intense: black

Question 20

What are the uses to mri?

Pros?

COns?

Answer 20

Further evaluate ct, tumors, infection, joint imaging

Pros: high level of detail, safe in pregnancy, vessel imaging w/o contrast

Cons: time consuming, cant use if metal devices, expensive, claustrophobia

Question 21

How will fluid appear in T1 weighted MRI?

Answer 21

Water/CSF = black (hypo-intense)

White matter: white

Good for visualizing normal anatomy

Question 22

How will fluid appear in a T2 weighted MRI?

Answer 22

Water/CSF = bright (hyper-intense)

White matter: dark

Good for visualizing pathology

Question 23

What is T2 FLAIR?

Answer 23

Removes CSF from a T2 mri

England fluid with high protein content that would then indicate edema/abscesses

(FLAIR: fluid attenuated inversion recovery)

Question 24

What is an ultrasound?

Pros?

Cons?

Answer 24

Noninvasive imaging technique using ultrasound waves

Used to evaluated carotid arteries, placement of central lines

Pros: non-invasive, cheap, no radiation

Cons: learning curve