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Flap 1

Flap 2

***Who is credited with inventing CT? in what year?

Godfrey Hounsfield in 1972

T/F Xrays are an excellent way to view facial and skul fractures?

No xrays SUCK for skull fractures - use a CT

List the Hounsfield units that's attenuated for each tissue in a CT?

Cortical Bone = +1000HU, Blood = +40HU, CSF = +15HU, Water = 0HU, Fat = -100HU, Air = -1000HU

What is a series of settings which affect the number of shades of gray displayed in a CT?

A window

What type of window allows you to see: 1. differentiation of cortical and medullary space? 2.allows visualization of muscle, organs, discs?

1.bone window 2.soft tissue window

1. What is the average CT number called? 2. What is the range of CT numbers above and below the window level called?

1.window level 2.window width

1.What is the window level of a bone window? 2.What is the window level of a soft tissue window?

1.bone window = +200HU 2.Soft tissue window = +20 to +40HU

What type of procedure is invasive, by injecting an agent within the subarachnoid space to indirectly visualize the subarachnoid space, spinal cord, and nerve root sheaths?

Myelography, not done much today unless patient is obese or claustrophobic and a MRI is impossible

What type of technique obtains "live xray images"?

Fluoroscopy

What type of technique uses high frequency sound waves to create an image of living tissue, tendons, and ligaments?

Ultrasound - remember it is non-ionizing but changes temperatures in tissue by 1 to 2 degrees.

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