Ultrasound

Question 1

What are the different probes and what are they used for?

Answer 1

Linear array – used for vascular work due to its flat surface

curvilinear - used for general and obstetric work the curved head allows for the beam to be angled – for example under the ribs

Transvaginal - Inside the vagina canal

Question 2

Name different scan techniques?

Answer 2

Transfer vaginal
Transrectal

Question 3

What can we examine in ultrasound?

Answer 3

Nearly all soft tissues
Foreign bodies x-rays can’t find
Abdomen
gynaecology
fertility
MSK
Hernia
Breast
Neonatal head
Baby hips
scrotum
obstetrics
vessels
biopsy guide

Question 4

Why is ultrasound Used?

Answer 4

Good soft tissue images

Minimal preparation

No radiation

Inexpensive

Quick

Tolerable for patient

Portable

Question 5

What is sound?

Answer 5

The transfer of energy from one place to another by series of collisions

(these collisions are between adjacent molecules in the medium through which the sound is passing)

Question 6

What is ultrasound?

Answer 6

Ultrasound is The Sound above 20 KHZ

This is above the level of human hearing

It has the same behavioural properties of sound we can hear

Question 7

How does sound travel best?

Answer 7

Solids are the most efficient due to the tightly packed molecules

The closer the molecules the faster than sound waves move through a medium.

(Like Chinese whispers)

Question 8

What is attenuation?

Answer 8

A Sound travels through a medium:

It loses energy

All media absorbs some of the waves energy

The sound can also be reflected - bounces back in the form of an echo - which is what we want in ultrasound


Question 9

How does ultrasound interact with tissue:

Answer 9

 Ultrasound is based on reflected – echo – rather than transmitted energy

When ultrasound interacts with a tissue the interactions are similar to the wave behaviour observed for light

Question 10

What is acoustic impedance?

Answer 10

Acoustic impedance is how much the energy medium wants to take away (absorbs)

different interactions – different appearance

When the two media for me interface have very different values of acoustic impedance a large fraction of the original sound will be reflected

For example the difference of air to tissue - 99% would be reflected

Conversely if there acoustic impedance between two structures are similar sound will be readily transmitted

The change of Acoustic impedance allows the visualisation of soft tissue structures with an ultrasonic beam

Question 11

How may ultrasonic beams interact with different tissues?

Answer 11

It may be:

absorbed

Passed through

Or reflected

Question 12

Why is gel used in ultrasound?

Answer 12

Gel is used to ensure ultrasound goes into the body through a gradual acoustic impedance

If there was no gel the ultrasounds would not go into the body

Question 13

The pulse Echo principle?

Answer 13

Distance = speed X time

Time interval between the generation of the original pulse of ultrasound and the detection of the returning echo - time

Knowledge of the speed of sound through the tissues - speed

These both allowers to estimate the total distance of the distance travelled by the pulse

• Probe – body – ultrasound monitor
  The time to reflect back enables the monitor to know how close to the skin surface the structure is

Question 14

Probe construction:

Answer 14

Acoustic lens

Acoustic matching layer

Piezo-electric element – transducer - PZT

Backing material

Question 15

Piezoelectric effect

Answer 15

Transducer + Energy – vibration(sound wave) (of the required frequency)

Goes in as an ultrasound pulse and reflects as an echo pulse

The sound waves then enter through the gel into the body (sound waves) - reflected back to the probe/transducer (piezoelectric crystal) where is picked up as a pulse - amplified to determine the pulse-echo return time- and then converted to a digital image on the ultrasound monitor

Question 16

Probe selection – frequency:

Answer 16

High-frequency – skinny:
- clear images but less penetration (loses energy)
– beam travels to shorter distance (superficial)

Low frequency – fat:
- poor image but can image deeper structures (doesn’t lose energy quickly)
– beam travels further (good penetration)
- not good detail (definition)
- absorbed by tissue - not good reflection

Question 17

What is frequency?

Answer 17

Frequency - number of occurrences of repeating event per unit of time

Question 18

Ultrasound artefact:

Answer 18

Acoustic enhancement – bright up
- fluid - less absorbed - goes straight through

Acoustic shadowing 
- all reflected

Question 19

What affects the image?

Answer 19

Patient size

Patient preparation

Probe and frequency

Question 20

Patient preparation?

Answer 20

 Full bladder for pelvic contents - Acts as a acoustic window - pushes bowel to the side and pushes uterus posteriorly

Fasted for a liver/gallbladder – allows gallbladder to fill with a bottle enabling visualisation of gallbladder wall and contents

Gas – beam is reflected – fast to prevent gas – can obstruct pancreas, duodenum, intestines

Question 21

What effect does the operator have on the ultrasound

Answer 21

Ultrasound is highly operator dependent

Qualification/experience – very vital as well as equipment knowledge

Question 22

Image interpretation in ultrasound:

Answer 22

What’s normal - very vital to know

Looking at size, shape, texture and Echogenicity - diagnosis

Organs should be imaged in two planes that are right angles to each other

Question 23

Image interpretation what should it look like normal?

Answer 23

For example liver parenchyma - Slightly more bright the cortex – too bright – fatty

Black – fluid

White – gas/bone/organ edge – reflective

Great – soft tissue

Question 24

Obstetrics

First trimester?

Answer 24

Conception to 12 weeks

Can do transvaginal 6 to 7 weeks

You get a 12 week scan

Question 25

What is the purpose of a 12 week scan in obstetrics?

Answer 25

To determine viability Exclude ectopic pregnancy Exclude multiple pregnancy - twins triplets Confirm gestation Exclude certain abnormalities - anencephaly Rule out ovarian pathology – large cyst Exclude uterine abnormalities – fibroids

Question 26

What can be seen in the first trimester – abnormalities?

Answer 26

 Normal – gestation sack which is the first sign of pregnancy Yolk sac - what are baby feeds off Seven week gestation – diamond ring sign An embryonic pregnancy Nuchal translucency Exomphalos Gastroschisis Ancephaly 

Question 27

Twins – first trimester?

Answer 27

Twin to twin syndrome – too much or too little it is an increased risk for identical twins or twins that share an Placenta Twins are scanned every two weeks

Question 28

What is An embryonic pregnancy?

Answer 28

– pregnancy continues to develop despite the absence of a fetus

Question 29

What is Nuchal translucency?

Answer 29

fluid at the back of neck – measure to determine risk of Down’s syndrome

Question 30

What is Examphalos?

Answer 30

weakness of babies abdominal wall where umbilical cord joins – chromosome problem – contents potrude outside The bigger it is the worse the prognosis

Question 31

What is Gastroschisis?

Answer 31

defective abdominal wall - intestines are outside of the body

Question 32

What is Ancephaly?

Answer 32

– malformation of large part of the brain/school/scalp is absent – incompatible with life

Question 33

Second trimester:

Answer 33

13 to 26 weeks Detailed anomaly scan at 20 weeks

Question 34

The purpose of the details scanned 20 weeks:

Answer 34

To confirm growth Reconfirm viability Determine structural abnormalities Boy or a girl Check the 4 chambers of the heart - valves, aorta, vessels Check the bread and cerebellum Check the feet - soft tissue markers – combination of symptoms - club feet Cleft lip – 4D image to help prepare patient – surgery to correct Spina bifida lack of folic acid Spine nerves are exposed Skin defect Paralysis 

Question 35

Third trimester:

Answer 35

Checking for: Growth – small/large for dates placenta site Presentation – position Follow-up of abnormalities Amniotic fluid volume Doppler umbilical artery

Question 36

what is placenta previa?

Answer 36

Cannot be fully digested till the third trimester Vaginal delivery not possible  Placenta partially or completely covers the cervical opening

Question 37

Umbilical artery Doppler:

Answer 37

Uteroplacental insufficiency - not enough oxygen Intra-uterine growth resection

Question 38

The liver:

Answer 38

Produces blood clotting stuff Filters Breaks down old or damaged blood cells And fat > energy  Metabolic processes – creates energy

Question 39

Liver – healthy versus damaged: appearance

Answer 39

Healthy smooth Fat deposits – bright Fibrosis scar tissue Cirrhosis - hard, lumpy, Chucky, unable to work -Fluid around due to breakdown of cells

Question 40

Lesions and mets:

Answer 40

All different some harder to find a pick up

Question 41

Contrast enhanced ultrasound: why? what can it find cost

Answer 41

To check vessels – blood flow pattern - Normal that middle - out - cartwheels - No storage cells – go straight out Nodular hyperplasia Liver lesions It’s cheap – £60 per patient - US CT – £300 per patient

Question 42

Possible hepatic system problems

Answer 42

Blockage of flow of bile - biliary colic and obstructive jaundice Stones come form in the system leading to biliary colic The gallbladder can become inflamed – cholecysitis Tumours or other obstructions at the level of the head of the pancreas can obstruct the flow of bile

Question 43

Vascular issues:

Answer 43

Thrombosis – Blockage/deep vein thrombosis – abdominal aneurysm- measure - size and location is very important May contain calcification or atheroma DVT – compress it to ensure the pain is compressible that means there is no thrombosis Veins at supposed to be black grey = thrombosis Varicose veins 

Question 44

Doppler ultrasound?

Answer 44

Red - flowing towards the probe Blue – flowing away from the probe

Question 45

Kidney cancer clinic –

Answer 45

50% of cancer is bilateral Work out what the next stage is stage one and two is contained stage three spread to Renal vein In clinic scan from renal vein - IVEC- nodes - liver - continue to find out extent

Question 46

Urinary bladder scanner

Answer 46

Check for the smooth Early – easy – straight to fluoroscopy - remove tumour Tumour can eat into bladder wall Roll the patient if it doesn’t move it’s not stones

Question 47

Gynaecology scanning:

Answer 47

ICUD – coils - ensure it’s in the uterine cavity Pregnancy- Ensure it has not perforated muscle Endo polyp - Heavy bleeding between period MSG - lining of cavity – guide to takeaway – nine out of 10 times it’s benign Ovarian mass Ovaries - they move around you need to know the patients stage of cycle to determine the pathology 1-7 no dominant follicles 10-13 follicles grow until they pop and egg comes out

Question 48

Fertility treatment:

Answer 48

Stimulate horrible to produce more focals Suction needle that to pop focals there should be eggs and they are then take it out

Question 49

Portable ultrasounds:

Answer 49

Renal, liver, DVT in ward  covid lung

Question 50

ECMO What is it and what does it stand for?

Answer 50

Extra Corporeal membrane oxygenation Outside the body – membrane oxygenator is a piece of equipment which delivers oxygen into the body Post ECMO - Hi risk of DVT

Question 51

Ultrasound MSK:

Answer 51

Commonly used in rheumatology and sports medicine Steroid injections can be given under ultrasound control

Question 52

Breast ultrasound:

Answer 52

For under 35-year-olds ultrasound is better Simple cyst - acoustic enhancement

Question 53

Testes and epididymi

Answer 53

Tumour hunting

Question 54

Hernia

Answer 54

Weakness of war Valsalva manoeuvre – used to increase pressure inside

Question 55

Neonatal radio:

Answer 55

Used to assess intracranial haemorrhage and hydrocephalus

Question 56

Baby hip ultrasound:

Question 57

FAST scan:

Answer 57

A and E to exclude internal bleeding Look for fluid between liver and kidney an spleen Less of a risk – better management CT for intestinal a journey - who needs it more