ultrasonography

Question 1

What is ultrasound?

Answer 1

Sound waves with frequencies higher than the human audible range

The upper limit for audible sound is considered to be approximately 20kHz

Question 2

predominantly, how does the ultrasound equipment get to the patient?

Answer 2

it is wheeled - can be taken to a patients bedside, which is an adv. if they aren’t mobile

can attach via USB to an iPhone – means paramedics have access to ultrasound equipment, and and search and rescue teams can take ultrasound images as soon as they find a patient and make their intial assessment, and the images can be sent to a trauma centre

Question 3

describe the pulse echo principle

Answer 3

the probe/transducer emits a sound wave, and then receives echoes from the original wave

whenever the ultrasound wave passes through a tissue boundary it can be:

• reflected back to the probe
• pass through the boundary and continue propagating through the body

adjacent tissues with varying densities will reflect more of the sound wave

the info that gets reflected back will be picked up by the transducer/probe and will be translated into an image

Question 4

what affects the brightness of an ultrasound image?

Answer 4

the amount of reflection: higher amount of reflection = brighter image

bright white relates to bone, predominantly around the facial bones and spine

Question 5

what does a dark image mean?

Answer 5

dark image means no information to be seen, nothing is reflecting back

dark areas = fluid

Question 6

name some clinical applications of ultrasound

Answer 6

cardiology
abdominal
urinary
gynaecology 
lungs
trauma
vascular
head/neck
breast/testicular
trauma

Question 7

why do we use ultrasound?

Answer 7

• usually non invasive
• no radiation
• no documented side effects
• “real time” imaging
• results available immediately
• widely accesible

Question 8

why might we not use ultrasound?

Answer 8

training is resource intensive

accuracy is user dependent

ultrasound image quality is dependent on patient habits

Question 9

there are many types of probes/transducers - why is this?

Answer 9

means you can get the most optimum image

for example, scanning something deep in the body means you would use a lower freq probe, and scanning something peripherally means you would use a higher freq probe

also, can use high frequency tipped probes and do an internal scan (intra vaginal scan on uterus or cervix), means you can see things in much finer detail

probe + catheter – take images of the lumen of a blood vessel wall

Question 10

all pregnant women in the UK are offered scans when?

Answer 10

at 12 and 20 weeks - 99% attendance rate

Question 11

purpose of a 12 week scan?

Answer 11

• making sure there is a fetus there and it has a heartbeat – “viability”
• checks number of fetus’ and gross anatomy ie. anecephaly, where the cranial vault hasn’t formed so the brain tissue leaks out into the fluid outside of the baby
• omphalocele is mid-gut herniation, which means mid-gut wall hasn’t closed properly and the content of their abdomen can become exterior to the body – can contain organs i.e. the liver

Question 12

how many pregnancies end in miscarriage?

Answer 12

1 in 4

Question 13

what is a blighted ovum?

Answer 13

a missed miscarriage

take a normal pregnancy test and it will be positive, your body will produce hormones to make you feel pregnant, periods will stop, gestational sac will grow but it will be empty

everything up until the ultrasound scan will make this person feel as if they’re pregnant

ask the patient to come back just in case the fetus is too small to be seen and they came too early to have a scan

Question 14

12 week Scan - Downs Syndrome screening?

Answer 14

optional part of the scan

Fetal nuchal translucency screening- uses ultrasound to measure the size of the nuchal pad at the nape of the fetal neck

Increased thickness of the sac of fluid = increased risk of downs syndrome

given a number and combined with a blood test generates a risk factor for the patient (eg. 1 in 30, 1 in 1000)

Question 15

The purpose of the 20 week scan?

Answer 15

to identify abnormalities:

• may indicate the baby has a life-limiting condition
• may benefit from antenatal treatment
• may require early intervention following delivery

ALSO

• Placenta localisation
• Fetal Biometry
• Fibroid Monitoring
• Liquor Assessment

baby is a bit bigger at 20 weeks, can get an idea of the finer anatomy and pick up some of the finer pathologies

estimate the weight of the baby based on the tummy circumference and measuring length of 1 thigh bones

Question 16

name some anomalies that can be seen in a 20 week scan

Answer 16

1. Spina Bifida
   - gap in spinal column which causes the spinal nerves and connective tissue to bulge through the spine and sit posterior to the baby’s back
2. Achondroplasia
   - dwarfism with varying degree of severity
   - x-ray shows slight bowled limbs, long bones bowed and shortened
3. Low Lying Placenta/Placenta Previa
   - placenta is usually out of the way of the internal os, as thats how the baby will leave, but here its sat on top of the cervix
   - baby won’t leave the cervix without tearing up the placenta
   - patient will need a c-section
4. Talipes (Club Foot)
   - -we have to make sure the baby moves the foot into a normal position, so you could do a 30 min scan or ask them to come back for another scan

Question 17

Polyhydramnios and Anhydramnios/ Oligohydramnios?

Answer 17

poly - a lot of amniotic fluid in the sac, often indicative of gestational diabetes or BP issues in the mum

anhy/oligo – no fluid/less amniotic fluid in the sac, poor prognosis as we cannot introduce fluid into the system– usually caused by some underlying chromosomal abnormality

Question 18

what is an ectopic pregnancy?

Answer 18

it is when an egg implants outside of the
uterine cavity

-associated with severe pain and bleeding
-can be caused by tubal damage
(from surgery, PIDS, endometriosis)
-treatment depends on the
Individual, medical or surgical - most common decision is termination

Question 19

multiple pregnancy - how does it happen and what are the complications?

Answer 19

Multiple pregnancy usually caused by delays in the fertilized egg reaching the womb before implanting

risk of growth restrictions (ie being too small), being competitive with each other and stealing each others blood supply is very high, so need serial scanning every 2 weeks

Question 20

Conjoined twins

Answer 20

very rarely have a positive outcome

Question 21

Twin to Twin Transfusion Syndrome

Answer 21

share a placenta

-rare, serious

Question 22

how can a cleft lip be seen?

Answer 22

3D imaging

Question 23

risks with amniocentisis

Answer 23

1 to 3 % miscarriage risk – don’t have to do them but only if really have to

Question 24

uses of ultrasound in Gynecology – fibroids, what are they?

Answer 24

fibrous muscular tissue, grow and grow until the blood supply they receive can no longer support growth, some require surgical intervention

can cause heavy or irregular periods

in pregnancy, if a fibroid is large enough it can create a physical obstruction to the cervix, or if its really large enough having that amount of muscular tissue pushing against the area where the baby is growing will cause restriction on the baby being able to grow

hormones helping the baby to grow can expedite the growth of the fibroids – important to monitor fibroid growth

Question 25

uses of ultrasound in gynecology – Post Menopausal Bleeding?

Answer 25

uterine polyps – growths from the inner wall of the womb which extend into the cervix and vagina.

usually benign but on rare occasion some can turn cancerous - surgery considered

polyps will continue to grow as they have a single feeder vessel – a larger blood vessel that supplies o2 to them – doppler ultrasound will pick this up

Question 26

abdominal ultrasound - aortic screening?

Answer 26

Patients over a certain age will be offered screening of their aorta

larger aorta size means its aneurysmal or pre-aneurysmal, and will be monitored over time

if the diameter of the aorta is over 3cm, patient is referred to vascular consultant and diameter is measured over time

if gets to 5cm they are offered a procedure, a graft through the aorta to divert where the blood flow is going, stops putting pressure on the aneurysm

Question 27

abdominal ultrasound - Liver Cirrhosis/Ascites?

Answer 27

people on long term medication/heavy drinkers/drugs – do they have cirrhosis/fibrosis of the liver?

different levels of drugs and alcohol can increase level of fat inside the liver, and more fat or fibrotic tissue inside the liver can decrease its function

over time this can become extreme

cirrhosis, liver looks more speckled

Question 28

abdominal ultrasound - gallstones?

Answer 28

• caused by an imbalance in chemical make up in bile in the gallbladder (high cholesterol / bilirubin)
• pain after eating (fatty food especially)
• occasional pain in right shoulder
• black pouch and inside is bright white speckles which are denser – US waves reflect more, therefore appear brighter

Question 29

urinary tract ultrasound - what can it detect?

Answer 29

1. Polycystic Kidney Disease
   - full of cysts, black areas which are pockets of fluid, grow over time
   - effectiveness of the kidney over time is massively reduced
2. enlarged prostate
3. renal calculi

Question 30

Testicular Ultrasound - what can it detect?

Answer 30

lumps
- usually little cysts, completely benign

could be testicular cancer

Question 31

Breast Ultrasound?

Answer 31

Under the age of 35 breast tissue tends to be denser, this leads to difficulty with diagnosing the nature of breast lumps on mammograms as differentiation between solid and fluid filled areas is relatively poor, ultrasound can make the differentiation at an improved rate (about 30% increased)

Ultrasound also enables core biopsies to be taken of breast lumps to allow for histological investigation to allow for classification of the lump.

Question 32

Vascular ultrasound?

Answer 32

used to exclude/confirm presence of a deep vein thrombosis when patient has in pain and swelling in lower limbs

also used as DVT screening tool in post operative patients and those with known pulmonary embolus (to find the source of the clot)

Question 33

Musculo-Skeletal Ultrasound?

Answer 33

Applications :

• Muscle/tendon tears
• Inflammation
• Nerve Entrapments
• Soft tissue lumps
• Cysts
• Hernias
• Paediatric CHD
• Infant Torticollis (neck twisting)

Question 34

POCUS – FAST

Answer 34

Point of Care Ultrasound – Focused Assessment with Sonography of Trauma

FAST is an ultrasound scan protocol undertaken at the time of presentation of a trauma patient.