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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