Ultrasound / ultrasonography Flashcards
Advantages of an ultra sound
- non invasive
- non ionising
- staging of diseases
- affordable
- view internal architecture
- assist in FNA
Disadvantages of an ultrasound
- sometimes poor images
- difficulty in image interpretation
- limitations to certain tissue types
Ultra sound modes
B mode - brightness mode
M mode - Movement mode
Doppler ultrasonography
Contrast ultrasonography
What does B mode do?
The normal mode used for real time 2D imaging of soft tissue
What does M mode do?
Real time echocardiography, uses b mode imaging in conjunction with this 1D image of the moving part. Images can be captured and frozen for measurement
What does Doppler ultrasonography do?
blood flow to and away from the probe produces sound waves of different wave lengths. these are assigned different colours in the image produced
Contrast ultrasonography
microbubb;es of sulphur hexafluoride gas in phospholipid capsules suspended in liquid injection IV highlights vascular structures and may help suggest malignancy
Uses of ultra sounds in small animals
- thoracic scannin
- abdominal us
- cardiac us
- obstetric us (Pregnancy)
Uses of ultra sounds on LA
- cardiac studies
- renal studies
- detect presence of pleural fluid
- liver studies
- ovarian studies
- obstetrics
- Tendon and ligament abnormalities
Patient prep for a US
clip hair all over the ROI (shaving the ROI reduces the amount of air between the transducer and the skin)
place coupling gel on the shaved area just prior to the exam (improves uninterrupted skin contact)
What does the ultra sound machine consist of
- a control body and panel
- Tv monitor for image display
- A recording device
- a transducer
What can you not use on a US machine
commercial cleaner
or
alcohol
What is a transducer
is the piece held in the hand of the user they contain crystals
what are the 2 types of transducers
- Linear transducers
2. Sector transducer
What is a linear transducer?
Are a wide and create a rectangle picture that has a wider near field than a sector transducer
What is a sector trandsucer
create a pie shaped picture and are good for looking inbetween ribs to image the heart. the near field is narrow and spreads out as it gets deeper.
What is an acoustic impedence
The ability of living tissue to resist or impede the sound waves
What is reflecting surface
where a sound wave meets an interface between 2 tissues of differing acoustic impedance
What is the image of a US
the image is a cross sectional picture of the internal architecture of the tissues being examined
List 3 ultrasound attenuation
- absorption - as heat
- reflection - beam is reflected and returned to the transducer
- Scattering - at small irregular surfaces only
what are the classified sound waves
- wave length
- Frequency
- velocity
less dense sound waves do what?
gives white echoes, and a grey image termed HYPECHOIC or ECHOPOOR
Absent of ecohoes or black scans are called black scans are called what?
ANECHOIC or ECHOLUCENT
What is an acoustic shadow.
Is a dark or anechoic area beneath a strongly reflective tissue
what are bright white echoes are termed what?
HYPERECHOIC or ECHOGENIC
what is an acoustic window
is a scan plane in the body which avoids gas, lung and bony structures
what can be picked up on an abdominal US
liver, gallbladder, spleen, kidneys, urinary bladder abnormalities
What is obstetric US
- evaluates pregnancy from 14 days
What does a cardiac US measure?
- wall thickness
- contractibility
