ultrasound Flashcards
There are three types of sounds in the spectrum name them.
infrasonic, acoustic and ultrasonic
infrasound has ……… frequency and ……… wavelength and therefore is not used in……
low
high
medical imaging
During ultrasound if one increases the frequency wavelength becomes …..
shorter
what is the purpose of a ultrasound transducer/pobe
converts electricity into sound and sound into electricity
what is the difference between a single-element transducer and a multiple-element transducer
single only includes one piezocrystal and is mainly used in vascular imagine whereas multiple has – lots of piezocrystals which fire off in groups to produce a ‘real-time’ image i.e. bladder patients.
why is jelly used during ultrasound
improves the transmission of sound as the probe doesn’t like differences in density and allows it for easy glide across the patient.
what is the role of density in ultrasound
Bone has a very high acoustic impedance, and air has a very low acoustic impedance but you don’t get any returning sound, human tissue is in the middle.
what is a doppler and why do we use it
Using sound to generate the Doppler effect (measuring blood flow without using contrast) biggest benefit without using contrast.
what are the three types of dopplers and there function
Colour doppler– red (towards the probe) and blue (away from the probe), very good vascular applications (can help characterise lesions, if there is blood flow = could be malignant)
- Used in cardio imaging and stroke patients.
Power Doppler – no specific colours, looks at flow, good for looking at lesions where there is no flow of blood in organs.
Spectral Doppler – quantify something I.e. blood flow through a vein, not very relevant.
…. frequency probes travel further but do not give …. resolution
lower and best
…. frequency probes travel further but do not give …. resolution
high and high
what type of frequency would be used for the thyroid
high
what frequency would be used for the liver
low
