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.
