PRACTICAL: Imaging methods

Question 1

outline how a ultrasound works to measure tissue thickness in 2 steps

Answer 1

1. Probe is placed on the skin in a sagittal plane, where the whole thickness of the muscle can be viewed
2. probe emits high-frequency sound waves that reflect back differently depending on the tissue structure, which is then detected by the probe

Question 2

what does probe in ultrasound allow for and what does this lead to?

Answer 2

• allows for anatomical focal points to be measured
• this leads to the thickness of the muscle to be measured using the boundaries of superficial and deep aponeurosis

Question 3

what is an aponeurosis?

Answer 3

a thin sheath of connective tissue that helps connect your muscles to your bones

Question 4

what is muscle thickness an important assessment of? (Ultrasound)

Answer 4

muscle thickness is an important assessment of muscle mass and changes in hypertrophy/atrophy

Question 5

what 2 things will thicker muscles have?

Answer 5

• greater contractile mass
• larger force production

Question 6

what are fascicles and how do they contract?

Answer 6

• contractile units of the muscle.
• contract linearly across their length

Question 7

fascicle lengths increase in response to…

Answer 7

muscle hypertrophy

Question 10

what does fasicle lengths increasing in response to muscle hypertrophy result in and why?

Answer 10

results in:

• greater force production
• this is because the length each fibre is able to contract will be greater

Question 11

what happens to pennation angle as fascicle length increases?

Answer 11

pennation angle decreases

Question 12

what does decreasing of the pennation angle allow for in muscle fibres?

Answer 12

allows for greater shortening of individual fibres

Question 13

what aspects are influencing the quality of muscle between a younger and older individual in sarcopenia cases

Answer 13

fat infiltration in between and within the muscles will decrease the quality of the muscle through reductions in the amount of contractile regions available as the total muscle mass is lost

Question 14

what body composition analysis method would be used to compare the bone density of twenty, 60-year old males vs twenty 60-year old females and why?

Answer 14

DXA scanner

• relatively quick
• automated bone density analysis

Question 15

what body composition analysis method can be used when comparing abdominal fat before and after an exercise intervention in 32 young adults and why?

Answer 15

• DXA
• because analysis of gross changes in adiposity can easily be determined based on regional analysis.

Question 16

what body composition analysis method would you use if you were determine if a group of 1000 children were overweight and why?

Answer 16

body weight scales

• because they are quick and simple to use

Question 17

what body composition method would you use to quantify levels of myosteatosis in 12 older (80-year-old men and why?

Answer 17

MRI

• allows more accurate quantification of muscle/fat although more time-consuming than other imaging techniques

Question 18

what body composition analysis method would you use to compare muscle mass of elderly intensive care patients compared to an age match group living in a care home to determine risk factors and why?

Answer 18

Ultrasound

• easy non-invasive measures which can accurately quantify muscle mass through muscle thickness