L44. Radiology: CT Scans Flashcards Preview

02. Cardiovascular > L44. Radiology: CT Scans > Flashcards

Flashcards in L44. Radiology: CT Scans Deck (10):
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What is computed tomography?

It is a three dimensional, computed image that provides a cross sectional view

1

How does computer tomography work?

A cathode ray tube passes through the tissues to a radiation detector that detects gas ionisation and converts it into a digital image

2

Give an analogy of how CT scans are taken and how the images are put together

It is analogous to a slinky with the detector spiralling around the body taking slices of images that are then digitally put together

3

What can post scanning processing achieve?

Can cut the image into any type of section

4

What are hounsfield unit?

A digital grey scale that measures the amount of xray attenuation. Most biological tissues lie within -100 to +100

5

Compare and contrast the spatial resolution, contrast resolution between X-rays and CT scans

X-ray has far better spatial resolution
CT has better contrast

6

What advantage does having contrast resolution have for CT?

Better ability to differentiate between soft tissues

7

What are the conventions for orientation of axial, coronal and
sagittal views for CT Imaging

Axial: from the feet up
Coronal: from the front
Sagittal: from the left

8

Is it necessary to describe the sections of the heart (as per X-rays)?

No because the fissures can be seen

9

What is a major disadvantage of CT imaging?

High dosage of ionising radiation
Expensive