Flashcards in Introduction to Medical Ultrasound Deck (63):
Uses safe sound waves and no radiation to allow visualization of the inside of the body
Emitting sounds and listening to the returning echos to locate objects or navigate
A computer programmed to transform sound echos into images
Ultrasound machine has piezoelectric crystal that vibrates to create sound waves and works in the
1-20 MHz range
Consists of a head with footprint, connector to make sound waves, and a wire
Must be in contact with the body mucus membrane
Assists sound waves to travel through the body cleanly
Different transducers emit sound at different frequencies allowing varying degrees of
Increases resolution at the expense of penetration
Have a higher frequency (10-18 MHz) and are used for musculoskeletal, soft tissue, and superficial analysis
A linear transducer works well up to about
6 cm penetration
Lower frequency transducers used on the abdomen and for deeper structures
Curvilinear or convex transducer
Has better penetration than a linear transducer, but worse resolution
What has a wider field of view, linear or curvilinear transducers?
Has a wide beam and a lower frequency. Helps to guide beams through windows such as the ribs
Sector (phased array) transducer
Sector transducers are used for
Give a rectangular image
What are the characteristics of B mode ultrasound?
2d spectra of shades of grey
Bright echos = more reflective tissues
No echos = not reflective (i.e. fluids)
Can be used to detect real time motion
B mode Ultrasound
Weak or low echo
No echo or blackness
Equal echogenicity between 2 structures
Ultrasound mode where red color indicates TOWARDS transducer and blue indicates AWAY from transducer
Doppler ultrasound is helpful in evaluating
5x more sensitive than doppler and is used to evaluate tumors or tendons
Used for low flow, and is one directional
What four things can happen to sound waves emitted from transducer?
1.) reflection back to transducer
Travel further and are LESS attenuated
Lower frequency waves
Used for deeper structures. Less resolution
Lower frequency waves
Used for superficial structures. Better resolution
Higher frequency waves
Artifacts occur because of normal physics of sound waves. One example of an artifact in ultrasound is
Change in echogenicity of a structure dependent on angle of beam relative to that structure
A 3-7 degree change in the probe position may drastically change the
The order of anisotrophic structures is
Tendon > ligament > nerve
Current resolution for ultrasound is 200-450 um. It can detect foreign bodies as small as
Ultrasound can even be used to detect
On an ultrasound machine, the gain button controls
Each musculoskeletal component (i.e. muscle, tendon, bone, cartilage, etc) has its own unique
In the sagital plane of muscle ultrasound, hypoechoic bundles are
In the sagital plane of muscle ultrasound, hyperechoic septae are
Fibroadipose and perimysium
Gives a multipennate pattern, like leaves on a leaf
Sagital muscle ultrasound
Gives an ultrasound that looks somewhat like starry night
Transverse muscle ultrasound
Non-compressible, non-vascular structures that connect muscle to bone
Tightly packed and hyperechoic. Best viewed using sagital ultrasound
In a transverse ultrasound of a tendon, what type of pattern do we see?
Bristle pattern, like the end of a broom
Compact packed fibrillar structure that often covers a capsule/joint to connect bone to bone
Ligaments are usually imaged in what plane?
Are ligaments vascular?
Ligaments can be hyper- or hypoechoic depending on
Gives a hyperechoic pattern with posterior shadows
Hypo-anechoic structures typically located at synovial joints
Bursae and Synovia
What type of echo does hyaline cartilage give off?
Hypoechoic with uniform thickness
Lines bones and is non compressible with uniform thickness
What type of echo does fibrocartilage give?
Hyper/hypo echoic. Like salt and pepper
In the sagital plane, which part of nerves show up as
In the short/transverse plane, nerves give what type of ultrasound?
A follicular pattern like a honeycomb
Are round and anechoic in the transverse plane
In the longitudinal section, vessels appear as
What method of ultrasound is great for vessels?
Allows us to see the body in motion so we can correlate movements with pain and pathology of a structure
A valuable tool for many procedures such as a central line or joint aspirations because it allows for great accuracy while decreasing much of the risk