Ultrasound Imaging and Muscle Function (WEEK 13)

Question 1

What is U/S imaging used for?

Answer 1

1. diagnosis of structural pathology - contusion, stress fracture
2. muscle function (morphology/behaviour):

Question 2

Rehabilitative U/S Imaging (RUSI) function

Answer 2

scope of practice used for:

1. Biofeedback to restore NM function
2. Perform research aimed at clinical practice
3. Evaluate morphology and function of muscle during physical task

Question 3

Real-time U/S (RTUS) How do we identify if a ligament is torn?

Answer 3

• RUSI the MCL while applying a values force

allows us to see the muscle change in real time

Question 4

Ultrasound soundwaves

Answer 4

2.5-15.0 MHz

electrical sound wave –> sound wave via transducer

Question 5

USI Image generation: Propogation/Reflection capacity

Answer 5

1. US wave characteristics

2. Tissue characteristics (acoustic impedance)

Question 6

Effect of acoustic impedance

Answer 6

Breaks up and dissipation as a results of: absorption, scatter, reflection due to different acoustic impedance

• adipose, fascia, muscle, bone

Question 7

How is image created?

Answer 7

Reflection: the transducer can determine where along the head it came back, the length of time it took to reflect back, amplitude of echo

superficial - pixel at top of image

deep - pixel at Botton of image

Question 8

Color pixel

Answer 8

intensity of echo

Question 9

fluid - why is it referred to as hypo or anechoic?

Answer 9

Fluid = poor reflection –> black

Question 10

Bone cortex - hyperechoic?

Answer 10

dense collagen are good at reflecting sounds –> white

Question 11

muscle vs. tendon - hyper or hypo?

Answer 11

muscle = collagen (unorganized) and blood = hypo (black)

tendon = more organized, dense = hyper (white)

Question 12

Define hyperechoic

Answer 12

medium that is more echogenic that surrounding tissue.

• appears whiter and brighter e.g. bone cortex, bone, dense fascia

Question 13

Define hypoechoic

Answer 13

medium that is less echogenic than surrounding tissue

- appears darker e.g. fluid

Question 14

Define echogenity

collagen vs. fluid

Answer 14

reflective property of tissue provides insight about composition

• collagen = > echogenicity (WHITE)
• fluid content =

Question 15

Architectural Characteristics

Answer 15

RUSI - compares differences/changes in parameters (shape, size, and other structural characteristics/pennation pattern

Question 16

Echogenicity: Low Back Pain findings

Answer 16

Conventional USI detect altered lumbar CT in persons with LBP

1. 25%>perimuscular thickness & echogenicity (WHITE)
2. factors? genetics, abnormal movement patterns, chronic inflammatino

Question 17

Architectural Characteristics: IAK injury

Answer 17

refers to size and shape

• conventional USI measures the CSA of vastis medals 3-10 years post intra-articular knee injury. 3.8x more likely to have difference in VM CSA > 15%

Question 18

Validity: USI and muscle

Answer 18

• good agreement (0.7-0.9) measurement of muscle size

Question 19

USI function:

Answer 19

tells us about muscle size but cannot tell us anything about why it is this way

Question 20

USI & EMG inconsistency

Answer 20

inconsistent correlation (e.g. RA, EO, IO, TA)

Question 21

Shape of muscle: Muscle activity

Answer 21

contract (shorten)

relax (lengthen)

Question 22

Shape of muscle: Resting state

Answer 22

increased/decreased resting length will affect the thickness and extensibility

Question 23

Shape of muscle: Resting activity

Answer 23

competing forces increase thickness of muscle(?)

e. g. Oblique tone & Intra-Abdmonial Pressure
(e. g. TA thicker in erect sitting that slouched)

Question 24

Shape of muscle: Out of plane changes

Answer 24

Depending on plane will affect the thickness of muscle

Question 25

Shape of muscle: type of muscle contraction

Answer 25

eccentric - thin | concentric - thick

Question 26

Factors that influence change in muscle shape

Answer 26

1. muscle activity 2. resting state (length and activity) 3. extensibility/structure of myofascial unit (muscle, tendon, fascia, pennation, lamentation) 4. Types of muscle contraction 5. Competing forces (e.g. abdmoninal muscles) 6. imagining technique (out of plane, body motion)

Question 27

``` Correctly Interpre4ng Dynamic USI Studies ```

Answer 27

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