application of ultrasound

Question 1

what benefit does ultrasound have over many other imaging modalities

Answer 1

real time assessment

Question 2

sonography is not a profession in its own right, in order to be registered they must hold a professional title

Question 3

what are the 2 forms of ultrasound

Answer 3

standard
portable

Question 4

what are the 2 types of portable ultrasound

Answer 4

• hand held connection to tablet or smart phone
• trolly or cart connected to laptop / laptop equivilant

Question 5

static machines can vary in size and capability with a range of functions

Question 6

smaller machines for single clinical settings

multifunctional amchinesas used in clinical imaging department

Question 7

what are the 3 general components of ultrasound

Answer 7

display monitor

transducer/probe

internal memory for image storage

Question 8

what are the 5 adjustable controls on the control panel of an ultrasound machine

Answer 8

• focus
• TGC
• gain
• depth
• zoom

Question 9

what are the 3 different probe types and the shape of their beam

Answer 9

linear = rectangle

curvilinear = cup shape (curved following probe surface but still running parallel) wide near and far field

phased array = cone shaped, tip closest to probe and widening going out (narrow near field, wide far field)

Question 10

what is linear probe good for

Answer 10

vascular small parts and intraoperative settings

Question 11

whats curvilinear probe good for

Answer 11

deep structures e.g obstetrics

Question 12

whats phased array prob good for

Answer 12

imaging through obstructions e.g ribs in cardiology

Question 13

what position is the patient usually in for xamination

Answer 13

supine

Question 14

what is acoustic couplant and why is it needed

Answer 14

gel, needed to transmit sound

Question 15

how would you position the patient to scan musculoskeletal e.g shoulder

Answer 15

sit upright on bed or chair

Question 16

what are the 2 main imaging modes

Answer 16

grey scale

doppler imaging

Question 17

what is grey scale mode imaging

Answer 17

• use of grey scale imaging in ultrasound renders a two-dimensional image in which the organs and tissues of interest are depicted as points of variable brightness.
• has modes A, B, M

Question 18

what are the 3 grey scale modes and what are they used to scan

Answer 18

A mode = simple ultrasound to measure distances (pulse echo)
(pinpointing structures)

B mode = bright mode, used for gaining 2d info (scanning plane)

M mode = motion mode, cardiology (excellent axial and temporal resolution)

Question 19

what are the 5 modes of doppler imaging

Answer 19

continuous wave dopple
pulsed wave doppler
power dopple
colour dopple
duplex dopple

Question 20

what is continuous wave dopple

Answer 20

• simultaneously transmits and receives sound waves with separate crystal elemennts
• displayed graphically as single line

Question 21

what is pulsed wave doppler

Answer 21

selected small area in b mode image and only doppler shifts from this area is recorded

Question 22

what is colour doppler

Answer 22

visualisation of flow direction and velocity within user defined area

Question 23

what is power doppler

Answer 23

uses amplitude of doppler signal to detect moving matter

Question 24

what 2 things is power doppler independent of and how is this beenficial

Answer 24

• independant of flow and velocity
• independent of angle

hence has higher sensitivity than colour doppler

Question 25

what is duplex doppler

Answer 25

combines colour doppler image with 2d greyscale image - allows more comprehensive analysis of blood flow and surrounding structures

Question 26

what might you see on image from doppler US if there is acute thrombosis

Answer 26

- increased venous diameter - soft intraluminar materia - smooth surface - free-floating edge

Question 27

what are some general sightings from doppler US

Answer 27

- loss of phasic flow on valsalva manoeuvre - absent colour flow if complete occlusion - lack of flow with calf squeeze - increased flow in superficial veins - non compressible venous segment

Question 28

how does bright mode imaging / B mode work

Answer 28

- sound waves emitted along axis of propagation - returning echoes detected by transducer and converted into electrical signals - electrical signal /voltage amplified and assigned various shades of grey pixels according to echo strength (acoustic impedance)

Question 29

how does the signal strength affect the colour on image give example

Answer 29

strong signals = brighter pixels e.g bone (as they are strong reflectors) known as hyper echoic or echogenic (bright) weaker signals = darker pixels (hypo echoic)

Question 30

what is obstetrics and why is it used

Answer 30

pregnancy ultrasound used to assess progression of fetus - number of foetus in womb - gestation of fetus - location of placent - fetal position - movement heart rates - amount of amniotic fluid in uterus

Question 31

what is FASP and when would this be done

Answer 31

The NHS Fetal Anomaly Screening Programme - done around 20th week of pregnancy as that is when structural anomalies begin to show

Question 32

what are the 2 ways that a pregnancy scan is done

Answer 32

trans-vaginally (early stage) trans- abdominally (in 2nd 3rd trimester)

Question 33

why might doppler ultrasound be used in obstetrics

Answer 33

- to measure blood flow to umbilical cord and uterine artery is theres suspicion that fetus is not growing properly from growth measurements

Question 34

3D/4D ultrasound only done for 'keepsake' purposed

Question 35

what is gynaecology and what is it used for

Answer 35

pelvic ultrasound or transvaginal ultrasound used to diagnose growths, tumours of ovary, uterus and Fallopian tubes

Question 36

what is GMUS scan and what sturctues are usually scanned

Answer 36

general medical ultrasound - abdomen - liver - gallbladder renal system

Question 37

what is a renal ultrasound used for

Answer 37

evaluate function and structure of kidneys - can assess size and shape of kidneys too

Question 38

what are the 3 limitations to using US/ what 3 procedures would u not used US for and why

Answer 38

- organs obscured by bowel (air and gas disrupts US waves via scatter) - obese patients (weaker signal when passing through more tissue) (also absorption and scattering) - internal structure of bone (cannot fully penetrate due to acoustic impedance but you can assess small fractures)