Diagnostic MSK ultrasound Imagine Flashcards
week 6
What is the basis of diagnostic ultrasound imaging?
Ultrasound is a cross-sectional imaging method based on sound waves reflected off soft tissues and tissue interfaces.
What happens to ultrasound waves in body tissues?
Ultrasound is partly absorbed, reflected, and diffused (through refraction and scattering).
What are hyperechoic structures?
Structures that reflect much energy, with reference to surrounding structures.
What are hypoechoic structures?
Structures that reflect little energy.
What are anechoic tissues?
Tissues that show no reflection.
What type of images do hyperechoic tissues produce?
Bright images due to high amplitude waves.
What type of images do hypoechoic tissues produce?
Dark images due to low amplitude waves.
How does frequency affect ultrasound resolution?
Both lateral and axial resolution improve with increasing frequency; higher frequency is better for superficial structures.
What is the relationship between frequency and wave penetration in ultrasound?
Lower frequencies are associated with longer waves that may penetrate tissues without returning a signal.
Which structures provide the highest amplitude signals in ultrasound?
Echogenic structures including cortical bone, tendons, and ligaments with smooth surfaces.
What structures are considered hypoechoic?
Cysts, bursae, and fat.
What is the normal appearance of cortical bone in ultrasound?
Hyperechoic, smooth, continuous.
What indicates a muscle strain in ultrasound imaging?
Disruption of fibrous bands; hypoechoic hematoma in early stages.
What characterizes a rupture in tendons and ligaments in ultrasound?
Disruption of structure, initially filled with hypoechoic hematoma, and separation of ends.
What is the appearance of hyaline cartilage in ultrasound?
Hypoechoic layer next to a hyperechoic cortex.
What are the advantages of ultrasound compared to MRI?
- Low cost and portability
- No contraindications; orthopedic hardware not a problem
- Ability to visualize structures not limited by orthogonal planes
- Continuous modification of imaging based on findings
- Palpation, stress, testing, and application of resistance while imaging.
What does ultrasound image better than MRI?
- Muscles: Architecture; imaging while testing with resistance
- Tendons: Fiber structure, degenerative changes, longitudinal tears
- Ligaments: Fiber structure, ability to stress test while imaging
- Cysts and bursae: Septations, debris less well seen on MRI.
What are the disadvantages of ultrasound in imaging joints?
Limited ability to show joint surfaces and intra-articular structures.
What does ultrasound reveal about bones?
Can only show the cortical outline of bone.
What is a limitation of ultrasound when scanning across lung fields?
Ultrasound does not cross air-tissue interfaces.
How does obesity affect ultrasound imaging?
Obese patients are not imaged well due to loss of acoustic energy and difficulty in obtaining the correct focal length.
How accurate is ultrasound for detecting full-thickness RCTs?
US is accurate for detecting full-thickness RCTs.
When should MRI be utilized in relation to ultrasound findings for RCT?
In patients with negative US findings for a full-thickness RCT but high clinical suspicion.
How accurate is ultrasound for diagnosing partial-thickness RCTs?
US is less accurate for diagnosing partial-thickness RCTs.
What diagnostic index was evaluated using ultrasound in relation to chronic lower back pain?
The thickness of the transverse abdominis muscle during simultaneous contraction.
What was concluded about TrA activity between college golfers with and without LBP?
No differences in TrA activity were observed.
