L44. Radiology: CT Scans Flashcards Preview

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

Flashcards in L44. Radiology: CT Scans Deck (10):

What is computed tomography?

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


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


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


What can post scanning processing achieve?

Can cut the image into any type of section


What are hounsfield unit?

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


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


What advantage does having contrast resolution have for CT?

Better ability to differentiate between soft tissues


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


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

No because the fissures can be seen


What is a major disadvantage of CT imaging?

High dosage of ionising radiation

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