Ultrasound Imaging and Muscle Function (WEEK 13) Flashcards Preview

PTHER 555 - Therapeutic Modalities > Ultrasound Imaging and Muscle Function (WEEK 13) > Flashcards

Flashcards in Ultrasound Imaging and Muscle Function (WEEK 13) Deck (27):
1

What is U/S imaging used for?

1. diagnosis of structural pathology - contusion, stress fracture

2. muscle function (morphology/behaviour):

2

Rehabilitative U/S Imaging (RUSI) function

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

3

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

- RUSI the MCL while applying a values force

allows us to see the muscle change in real time

4

Ultrasound soundwaves

2.5-15.0 MHz
(electrical sound wave --> sound wave via transducer)

5

USI Image generation: Propogation/Reflection capacity

1. US wave characteristics
2. Tissue characteristics (acoustic impedance)

6

Effect of acoustic impedance

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

- adipose, fascia, muscle, bone

7

How is image created?

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

8

Color pixel

intensity of echo

9

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

Fluid = poor reflection --> black

10

Bone cortex - hyperechoic?

dense collagen are good at reflecting sounds --> white

11

muscle vs. tendon - hyper or hypo?

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

tendon = more organized, dense = hyper (white)

12

Define hyperechoic

medium that is more echogenic that surrounding tissue.

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

13

Define hypoechoic

medium that is less echogenic than surrounding tissue
- appears darker e.g. fluid

14

Define echogenity

collagen vs. fluid

reflective property of tissue provides insight about composition

- collagen = > echogenicity (WHITE)

- fluid content =

15

Architectural Characteristics

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

16

Echogenicity: Low Back Pain findings

Conventional USI detect altered lumbar CT in persons with LBP
1. 25%>perimuscular thickness & echogenicity (WHITE)
2. factors? genetics, abnormal movement patterns, chronic inflammatino

17

Architectural Characteristics: IAK injury

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%

18

Validity: USI and muscle

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

19

USI function:

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

20

USI & EMG inconsistency

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

21

Shape of muscle: Muscle activity

contract (shorten)
relax (lengthen)

22

Shape of muscle: Resting state

increased/decreased resting length will affect the thickness and extensibility

23

Shape of muscle: Resting activity

competing forces increase thickness of muscle(?)

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

24

Shape of muscle: Out of plane changes

Depending on plane will affect the thickness of muscle

25

Shape of muscle: type of muscle contraction

eccentric - thin
concentric - thick

26

Factors that influence change in muscle shape

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)

27

Correctly
Interpre4ng
Dynamic
USI
Studies

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