Neuro Other

Question 1

What is first choice imaging for ENT?

Answer 1

CT

Question 2

What imaging modality may be used in the setting of trauma and is commonly used regarding degenerative issues of the spine?

Answer 2

radiography

Question 3

the selection of what shades of gray in an examination are viewed on the computer monitor at any one time is called…

Answer 3

windowing

Question 4

radiographic densities on a CT are described as attenuation and different attenuations are measured in what units?

Answer 4

Hounsfield units

Question 5

What has a Hounsfield unit of 0?

Answer 5

water

Question 6

Average of brain tissue in Hounsfield units would be about what?

Answer 6

+35

Question 7

In the body, on one CT, what could the span of Hounsfield units be?

Answer 7

2000 units - potentially 2000 shades of gray

Question 8

How many shades of gray can the human eye detect?

Answer 8

20-70 shades

Question 9

What four windows do we most often use when interpreting a head CT?

Answer 9

• brain window
• bone window
• blood or subdural window
• soft tissue window

Question 10

The window level selected is usually…

Answer 10

the middle value from the Hounsfield units that the tissue you want to see, has

Question 11

The width of the window you select needs to be…

Answer 11

wide enough to include all of the Hounsfield units that that particular tissue may have

Question 12

All tissues with Hounsfield units lower than what is included in your window will appear…

Answer 12

black

Question 13

A subdural window is ideal for observing…

Answer 13

a subdural hematoma, but would probably obseer most any intracranial hemorrhage.

Question 14

Generally, does grey or white matter have more attenuation? Why?

Answer 14

grey has greater attenuation because it has more blood and less myelin

Question 15

cytotoxic edema is normally thought of in ischemia and acute stroke. On the cellular physiology level, what is happening?

What is seen on CT?

Answer 15

ATP Na-K pump can no longer function so Na increases inside the cell, drawing in extracellular water, causing the cell to swell

on CT as a loss of the grey-white distinction

Question 16

What is the main difference between cytotoxic edema and vasogenic edema?

Answer 16

cytotoxic edema has the BBB still intact and in vasogenic edema, BBB is not intact

Question 17

How can you tell the difference on CT of vasogenic edema v cytotoxic edema?

Answer 17

cytotoxic edema - grey matter becomes less attenuated, becoming more like white and losing the grey white junction

vasogenic edema - attenuation of white matter goes down, making the grey white junction exaggerated

Question 18

intra-axial means that the location of something is…

Answer 18

within the spinal cord or brain

Question 19

What does an epidural hematoma look like? What kind of bleed usually causes it?

Answer 19

lens shape or biconvex

does not cross suture lines

usually arterial bleed, such as middle meningeal artery

Question 20

pt is younger, has had head trauma, and might have skull fx, what kind of bleed?

Answer 20

epidural hematoma

Question 21

pt is older, may or may not have known trauma, pt has a …

Answer 21

subdural hematoma

Question 22

What shape is a subdural hematoma? What kind of bleed is it usually from? Can they cross suture lines?

Answer 22

cresecent

venous, subdural vein bleed

can cross suture lines

Question 23

What kind of bleed may be spontaneous, from a ruptured cerebral aneurysm?

Answer 23

subarachnoid hemorrhage