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Flashcards in CT and MRI Deck (28):
1

what are the main advantages of CT/MRI?

 

contrast resolution 

tomographic imaging 

2

T/F contrast resolution of DR, CT and MRI can be manipulated post processing 

True 

3

what is tomography?

images are slices of patient 

solves 2D problems of planar images 

4

computed tomography (CT) 

Computed: images are created from digital information

  • Quantification of x-ray attenuation

Tomography: images are slices from the patient

5

what are CT images based on?

x ray attenuation (absorption)

  • X-ray beam rotates around patient
  • Transmitted beam intensity measured by detectors
  • Computer reconstructs image

 

6

what is 2D reformatting

building images in other planes from transverse data 

7

what is 3D reformatting useful for?

understanding complex lesions 

8

when is contrast medium commonly used?

to enhance visability of blood vessels, vascular leaks and the GI tract 

9

CT uses:

Nasal disease

Thoracic masses; resectable

Fragmented medial coronoid process (elbow disease) 

Radiation therapy planning

Portal vein anomalies

10

what is image appearance dependent upon with MRI?

 

water (free vs. tissue) 

fat 

11

T/F contrast resolution is much better with CT than MRI

False

MRI has better contrast resolution 

12

T/F MRI uses ionizing radiation 

False

has nothing to do with x rays 

13

how does MRI work?

 

very strong magnetism 

14

what is being imaged with MRI?

hydrogen protons i.e. water 

(most lesions have increased water) 

15

with proton densty the magnet primarily "hears"

all protons 

16

with T1 the magnet primarily "hears"

protons in fat

17

with T2 the magnet primarily "hears"

protons in free water, tissue water (edema, interstitial, etc), and fat 

18

with FLAIR the magnet primarily "hears"

(Fluid Attenuated Inversion Recovery) 

protons in tissue water 

(most lesions alter this) 

19

with STIR the magnet primarily "hears"

(Short Tau Inversion Recovery) 

nulls signal from fat 

20

which sequence shown

T2

21

which sequence is shown 

T1

22

which sequence is shown 

FLAIR

23

Which sequence is "A"

T2

most lesions, such as infarcts, result in increased tissue water

24

which is an example of FLAIR

B

nulls signal from free fluid, i.e. CSF 

25

when is Godolinium contrast used?

detection of defective BBB or inflammation 

used only in T1 sequences 

26

applications of MRI in vet med

 

Neuroimaging

musculoskeletal 

tumor staging 

27

what kind of image is this

CT

28

what sequence of MRI is this 

T2-weighted