W2- Ultrasound Imaging Flashcards
“The generation of images using reflected ultrasound and measuring the difference between emitted and received ultrasound.”
Ultrasound
Describe the Production and Reception of US.
Production
- Current applied to crystal causes oscillations at the base frequency, creating ultrasound beam.
- Beam applied through soft tissue.
Reception
- Reflected beam received by crystals, causing charge.
- From this data, image is constructed.
- Where is the US beam intensity greatest?
- What is the Focal Zone?
- Greatest at center.
- Focal Zone = narrowest zone along long axis
What is the difference between a longitudinal and transverse sonogram?
Longitudinal Sonogram
-Long axis of transducer aligned to long axis of structure.
Transverse Sonogram
-Transducer applied across structure.
- How big is the field of view when performing US?
- What is extended field of view?
- Only as big as the long axis of the transducer.
- Extended field of view displays frames acquired sequentially.
Cortical Bone normal and abnormal US characteristics.
- Normal = Hyperechoic (bright), smooth, continuous
- Abnormal = Break in continuity, uneven surfaces.
Tendons/Ligaments normal and abnormal (strains/sprains) US characteristics.
- Normal = Hyperechoic; distinct parallel fiber pattern
- Abnormal = Strain; Thickening of mixed echogenicity (hypoechoic if inflammation or hematoma), disrupted fiber pattern. Rupture; Disruption of structure, initially filled with hypoechoic hematoma, and separation of ends.
Muscle normal and abnormal US characteristics.
- Normal = Hypoechoic, with parallel fibrous hyperechoic bands.
- Abnormal = Strain; Disruption of fibrous bands, hypoechoic hematoma in early stages. Rupture; Retraction of muscle.
Bursa normal and abnormal US characteristics.
- Normal = Thin hypoechoic line.
- Abnormal = Increased width of bursa. In later stages, hyperechoic thickening of bursa walls.
Hyaline Cartilage normal and abnormal US characteristics.
- Normal = Hypoechoic layer next to cortex.
- Abnormal = Early changes display as inhomogeneous thickening, later irregularity and disruption.
Nerve normal and abnormal US characteristics.
- Normal = Hyperechoic, relative to muscle.
- Abnormal = Flattening, swelling proximal to compression.
Cysts normal and abnormal US characteristics.
- Normal = Anechoic
- Abnormal = Increased volume, thickened walls, septations, debris.
What is a Doppler Ultrasound?
A Doppler ultrasound is a noninvasive test that can be used to estimate the blood flow through your blood vessels by bouncing high-frequency sound waves (ultrasound) off circulating red blood cells.
Doppler US
- When moving toward the transducer, sound waves reflected off of blood cells arrive at the transducer _______.
- When moving away from the transducer, sound waves reflected off of blood cells arrive at transducer _______.
- faster
- slower
Doppler US provides information on what (3) things?
- Presence of blood flow.
- Direction of blood flow. (red (artery) vs. blue (vein))
- Gross circulation abnormalities.
Blood flowing through narrowed foramen (stenosis) characterized with __________ speed and turbulence.
increased
Clinical Indications and Benefits of USI. (11)
- Identification/Differentiation of MSK lesions
- Real-time Assessment
- Biofeedback (RUSI)
- Continuous Monitoring of Health Conditions
- Doppler US
- High-res Soft Tissue Imaging
- Minimally affected by metal artifact
- Enables rapid contralateral exam for comparison
- Portable/Inexpensive
- No radiation
- No contraindications
What are the advantages of USI over MRI when assessing these structures:
- Muscles
- Tendons
- Ligaments
- Cysts/Bursae
Muscles
-Architecture; imaging while testing resistance.
Tendons
-Fiber structure, degenerative changes, longitudinal tears.
Ligaments
-Fiber structure, ability to stress test w/ imaging.
Cysts/Bursae
-Septations, debris not seen on MRI
What are the disadvantages of USI over MRI when assessing these structures:
- Joints/Intra-articular Structures
- Bones
- Scanning across Lung Fields
Joints/Intraarticular Structures
-Limited ability to show joint surfaces and intra-articular structures.
Bones
-Can only show cortical outline of bone.
Scanning Across Lung Fields
-US does not cross air/tissue interfaces.
USI Common Clinical Applications. (9)
- Tendinopathies
- Muscle strains
- Front-line diagnostics for patient’s with shoulder pain
- Assessment of superficial areas of joint
- Post-op assessment
- Joint stability with dynamic stress testing
- Peripheral nerve compression
- Superficial disruption of bone cortices
- Inflammatory arthropathies
