Questions and Answers
What type of ultrasound shows movement as a function of time and is utilized in cardiac scanning?
What effect describes the change in frequency of a wave due to the relative motion between the observer and the source?
Which mode of ultrasound displays echoes as peaks to measure distances between structures?
What is the primary function of a piezoelectric crystal in ultrasound technology?
Signup and view all the answers
Which of the following best describes B-mode imaging in ultrasound?
Signup and view all the answers
Which Doppler ultrasound unit is designed to continuously measure high velocities?
Signup and view all the answers
What happens to the reflected echoes when a reflector moves closer to the source?
Signup and view all the answers
Which type of crystal diameter increases beam divergence in ultrasound technology?
Signup and view all the answers
What is the primary purpose of a transducer in an ultrasound system?
Signup and view all the answers
Which type of transducer utilizes piezoelectric crystals?
Signup and view all the answers
What happens to energy transmission when there is a large difference in acoustic impedance?
Signup and view all the answers
Which ultrasound transducer is best suited for imaging deep lying structures?
Signup and view all the answers
What characteristic of the linear array transducer defines its field of view?
Signup and view all the answers
What is the most expensive component of an ultrasound unit?
Signup and view all the answers
Which transducer is best utilized for cardiac and cranial ultrasound due to its wide field of view?
Signup and view all the answers
A transducer with parallel scan lines is known as what type?
Signup and view all the answers
Which of the following materials is NOT a piezoelectric element?
Signup and view all the answers
Which frequency characteristic is true regarding higher frequencies in ultrasound imaging?
Signup and view all the answers
What does the acoustic lens primarily improve in ultrasound imaging?
Signup and view all the answers
Which option correctly describes the piezoelectric effect?
Signup and view all the answers
What role does the thin film of gold or silver play in a transducer?
Signup and view all the answers
Which factor determines the lateral resolution in ultrasound imaging?
Signup and view all the answers
What material is NOT mentioned as a component for piezoelectric elements?
Signup and view all the answers
Which statement about lower frequencies in ultrasound is correct?
Signup and view all the answers
Which type of ultrasound transducer is best for later pregnancy?
Signup and view all the answers
What is a benefit of using backing/damping materials in ultrasound?
Signup and view all the answers
What characterizes a wide bandwidth ultrasound pulse?
Signup and view all the answers
In the two regions of an ultrasound beam, which zone is referred to as the near field?
Signup and view all the answers
For neonatal brain scans, which ultrasound transducer frequency is typically preferred?
Signup and view all the answers
Which material is NOT commonly used in the context of ultrasound for impedance matching?
Signup and view all the answers
What is a characteristic of the far field in an ultrasound beam?
Signup and view all the answers
Which of the following best describes the function of the impedance matching layer in ultrasound?
Signup and view all the answers
What causes acoustic shadowing in ultrasound imaging?
Signup and view all the answers
Which scenario is most likely to lead to edge shadowing effects?
Signup and view all the answers
What primarily leads to diverging ultrasound beams?
Signup and view all the answers
Acoustic enhancement occurs due to which type of structure?
Signup and view all the answers
What is a primary concern related to the mirror image artifact in ultrasound?
Signup and view all the answers
What is a common location where acoustic enhancement can often be observed?
Signup and view all the answers
Which factor does NOT contribute to beam width artifact?
Signup and view all the answers
What causes the beam to deviate while traveling through tissue?
Signup and view all the answers
Study Notes
Electrical Energy to Mechanical Energy
- Piezoelectric crystals convert electrical energy into sound (mechanical energy).
- Used in M-mode ultrasound, showing movement over time.
- Dangers of size: smaller crystal diameters increase beam divergence, while larger diameters decrease it.
Piezoelectric Crystal
- Converts mechanical energy (sound) back into electrical energy for imaging.
- Found in heart monitoring applications, particularly in cardiac scanning.
Doppler Technology
- Doppler ultrasound measures blood flow and velocity.
- The Doppler effect describes frequency changes due to motion relative to a source.
- If the reflector moves closer, echoes are higher frequency than transmitted.
- If the reflector moves away, echoes are lower frequency.
Ultrasound Modes
- A-mode: Echoes represented as peaks; useful in measuring distances, contributes to 2D imaging.
- B-mode: Displays two-dimensional images; echo amplitudes shown as varying brightness dots.
Basic Types of Doppler Ultrasound Units
- Continuous Wave Doppler: Measures high velocities accurately; ultrasound emitted continuously.
- Pulsed Doppler: Allows for depth resolution and measures slower velocities.
Transducer/Probe Overview
- A transducer converts energy forms, generating ultrasound waves from electrical energy.
- Contains piezoelectric crystals for transmission and reception of sound waves.
Types of Transducers
- Linear Array Transducer: Creates parallel scan lines; optimal for vascular applications.
- Sector/Curvilinear Array Transducer: Offers wide field of view; common in obstetric imaging.
- Phased Array Transducer: Flat design providing a wide field; used for cardiac and cranial scans.
Components of a Typical Transducer
- Physical Housing: Houses components and provides structural support; acts as an insulator.
- Electrical Connections: Thin films of gold/silver connect to piezoelectric crystals.
- Piezoelectric Elements: Generate voltage when mechanically stressed; materials affect performance.
- Acoustic Lens: Narrows beam width; improves image resolution.
- Impedance Matching Layer: Enhances energy transmission into the body.
Frequency and Image Quality
- Higher frequencies lead to better resolution but less penetration; lower frequencies allow deeper penetration with reduced resolution.
- Bandwidth varies: Wide bandwidth ensures a shorter spatial pulse length.
Selecting the Appropriate Transducer
- Obstetric Ultrasound: Often utilizes linear or convex transducers; frequency varies based on gestation.
- Pediatric Ultrasound: Specific transducers for varying age groups in diagnostics.
Ultrasound Beam Characteristics
- Comprises two zones:
- Near Field/Fresnel zone.
- Far Field/Fraunhofer zone, where the sound diverges further.
- Beam divergence occurs due to diffraction as it travels through diverse tissues.
Ultrasound Artifacts
- Artifacts may misrepresent true tissue structures, commonly found in fluid-filled areas.
- Forms include acoustic shadowing and enhancement, edge shadowing, and mirror image effects, impacting diagnostic accuracy.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz focuses on the role of piezoelectric crystals in converting electrical energy to mechanical energy, specifically in sound applications such as M-mode and Doppler ultrasound. Explore how these technologies are used in cardiac scanning and how they demonstrate blood flow over time.
