introduction to sonography Flashcards
Change in direction of propagation of a Soundwave transmitted across an interface where the speed of sound varies
Refraction
Sound transmitted and received intermittently with one transducer
Pulse wave
An easy and effective way to measure heart rate
Pulse
Amount of time the piezoelectric element vibrates after electrical stimulation
Pulse duration
Ability to compensate for attenuation of the transmitted beam as the sound wave travels through tissue in the body
Time gain compensation
Convenient, noninvasive method of monitoring oxygen levels in the blood
Oximetry
Speed of ultrasound wave; determined by tissue density
Velocity
Change in frequency of reflected wave; caused by motion between the reflector and the transducers beam
Doppler shift
Refers to observable and measurable signs of life
Vital signs
Special material in the transducer that has the ability to convert electrical impulses into sound waves
Crystal
Minimum distance between two objects located side by side at which they can be displayed as seperate objects
Lateral resolution
One transducer continuously transmits sound, and one continously receives sound; used in high velocity flow patterns
Continuous wave doppler
Device for delivering oxygen by way of two small tubes inserted into the nostrils
Nasal cannula
The product of the velocity of sound in a medium and the density of that medium
Acoustic impedance
Unit of frequency; equal to one cycle per second
Hertz
Normal pattern of vessel flow; flow in center of vessel is faster than at edges
Laminar flow
Shortness of breath or feeling of not getting enough air
Dyspnea
Study of generating, propagating, and receiving soundwaves
Acoustics
Unit used to measure intensity. Amplitude, and power of an ultrasound wave
Decibel
Device that converts energy from one form to another
Transducer
Has large diameter with multiple rings of focus
Annular array
Rate at which images are updated on the display; dependent on transducer frequency and depth selection
Frame rate
Analysis of entire frequency spectrum
Spectral analysis
1000 hz
Kilohertz
Limit when technical artifacts that occur when the frequency change is so great that it exceeds sampling view
Aliasing
Spontaneous breathing that stops for any reason
Apnea
Exists when systolic pressure is above 140mmHg, but diastolic pressure remains below 90mmHg
Isolated systolic hypertension
Ability of the system to accurately depict motion
Temporal resolution
Activates a limited group of adjacent elements to generate each Pulse
Linear array
Represents a national movement to recapture the respect and goodwill of the American public
Patient focused care
Reduction in amplitude and intensity of a sound wave as it propagates through a medium
Attenuation
Process of inhaling and exhaling air
Respiration
Surface forming the boundary between media having different properties
Interface
Contact with or bites from an insect or animal are a type of
Contact transmission
The angle that the reflector path makes with the ultrasound beam is the
Doppler angle
Surgical procedure to create an opening to allow passage of contents of the urinary bladder or bowel through the abdominal wall
Ostomy
Practice of giving liquid substances directly into a vein
Intravenous therapy
The higher number is the ___________ pressure, which occurs when the ventricles contract to pump blood
Systolic
Supplies electrical signals to the transducer for producing a sound beam
Crystal
Basic infection control guidelines used to reduce the risks of infection spread through these transmission modes: airborne, droplet, and contect
Standard precautions
Refers to the minimum distance between two structures positioned along the axis of the beam where both structures can be visualized as separate objects
Axial resolution
National standard created to protect individuals medical records and other personal health information
Hippa
Displays time and movement, especially in cardiac structures
M-mode
Imaging provides a dynamic presentation of multiple image frames per second over selected areas of the body
Real-time
Refers to the correct muscles to complete a task safely, efficiently, and without undue stress on the joints or muscles
Body mechanics
B-mode scanning technique that permits the brightness of the B-mode dots to be displayed in various shades of gray to represent different echo amplitudes
Gray scale
Hospital acquired infection
Nosocomial infection
1,000,000 Hz
Megahertz
Amount of change in the returning frequency compared with the transmitting frequency when the sound wave hits a moving target such as blood in an artery
Frequency shift
Ability of the transducer to distinguish between two structures adjacent to one another
Resolution
Determines the strength of the pulse transmitted into the body
Power output
Sample site from which the signal is obtained with pulsed doppler
Gate
Most common arrhythmias
Bradycardia tachycardia
Ultrasound defined as frequencies between
1-20 Mhz
Three qualities of a good sonographer
- Intellectual curiosity
- Quick, analytical mind
- Technical aptitude
Sound is result of mechanical energy that produces alternating ________ and _______ of conducting medium as it travels as a wave
Compression
Rarefaction
A transducer converts _____ energy into _______ energy
Mechanical
Electrical
The time required to produce each cycle depends on the __________ of the transducer
Frequency
Normal transmission of sound through soft tissue travels at
1540 m/s
Lateral resolution is determined by
The width of the soundbeam
If the gain is set too ______, artifactual echo noise will be displayed throughout the image
High
When the nyquist limit is exceeded, an artifact called ________ occurs
Aliasing
What muscles should lifting be done with?
Leg
Airborne diseases
Tuberculosis
Measles
Chicken pox
Shingles
Droplet diseases
Mumps Pneumonia Strep Whooping cough Meningitis Measles
Name one of the most serious contact diseases
Mrsa
When transferring patients with ivs you should never
Lower the iv bag below the level of needle insertion
Reflector path less than 60 degrees
Doppler angle
Change in frequency
Doppler shift
Normal amount of oxygen in the blood
90%
How many bpm is normal adult respiratory rate
15-20
How many bpm is normal adult pulse rate
60- 80
An iv container should always be _________ centimetres above the level of the patients vein
18-20
If the reflector is moving toward the transducer, the frequency of the echo will be ________ than the transmitted frequency
Higher
The higher the transducer frequency, the
Shorter the wavelength
Difference between transmitted and received frequency is called
Doppler frequency shift
If the Doppler angle of the beam to the reflector exceeds 60 degrees,
Velocities will no longer be accurate
_____ occurs when the pulse encounters an interface between tissues with different acoustic impedances
Reflection
Basic mode for all real time imaging
B-mode
Uses one transducer
Pulsed wave transducer
