imaging of tissues (includes types of imaging)

Question 1

how do we image tissues?

Answer 1

X-ray source, subject and image receptor

Question 2

interaction of x-rays with tissues

Answer 2

• pass through tissue
• beam is attenuated and reduced in intensity

Question 3

5 x-ray densities

Answer 3

air, fat, soft tissue, bone and metal

Question 4

types of bones

Answer 4

compact + spongy

Question 5

compact bone

Answer 5

cortex, outer edge of bone

Question 6

spongy bone

Answer 6

marrow, not as compact or dense

Question 7

trabecular patterns

Answer 7

stress on the bone can be due to pressure from exercise

Question 8

examples of different types of tissues

Answer 8

nervous, connective + muscle

Question 9

CT

Answer 9

• cross-sectional images of anatomy
• can produce images in other planes
• contrast media may be introduced to enhance organs, vessels, GI tract

Question 10

MRI

Answer 10

• images in three planes
• basis of hydrogen content
• allows greater differentiation of soft tissue such as tendons and ligaments

Question 11

ultrasound

Answer 11

• shows soft tissue in good detail
• tissues have different echoic properties such as hyperechoic, hypo echoic, anechoic

Question 12

nuclear medicine

Answer 12

• demonstrates function rather than anatomy
• injection of radioactive tracer
• demonstrates metabolic activity

Question 13

drawbacks of MRI

Answer 13

• time consuming
• claustrophobia
• metalwork

Question 14

drawbacks of CT

Answer 14

• high radiation dose
• some patients allergic to contrast

Question 15

drawbacks of ultrasound

Answer 15

• needs trained staff
• not as readily available: out of hours

Question 16

drawbacks of X-ray

Answer 16

• 2D imaging
• can’t do reconstructions
• limited soft tissue detail

Question 17

drawbacks of nuclear medicine

Answer 17

• not available out of hours
• long scan times
• allergies