Ultrasound Flashcards
What are the different probes and what are they used for?
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
Name different scan techniques?
Transfer vaginal
Transrectal
What can we examine in ultrasound?
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
Why is ultrasound Used?
Good soft tissue images
Minimal preparation
No radiation
Inexpensive
Quick
Tolerable for patient
Portable
What is sound?
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)
What is ultrasound?
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
How does sound travel best?
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)
What is attenuation?
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

How does ultrasound interact with tissue:
 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
What is acoustic impedance?
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
How may ultrasonic beams interact with different tissues?
It may be:
absorbed
Passed through
Or reflected
Why is gel used in ultrasound?
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
The pulse Echo principle?
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
Probe construction:
Acoustic lens
Acoustic matching layer
Piezo-electric element – transducer - PZT

Backing material
Piezoelectric effect
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
Probe selection – frequency:
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
What is frequency?
Frequency - number of occurrences of repeating event per unit of time
Ultrasound artefact:
Acoustic enhancement – bright up
- fluid - less absorbed - goes straight through
Acoustic shadowing 
- all reflected
What affects the image?
Patient size
Patient preparation
Probe and frequency
Patient preparation?
 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
What effect does the operator have on the ultrasound
Ultrasound is highly operator dependent
Qualification/experience – very vital as well as equipment knowledge
Image interpretation in ultrasound:
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
Image interpretation what should it look like normal?
For example liver parenchyma - Slightly more bright the cortex – too bright – fatty
Black – fluid
White – gas/bone/organ edge – reflective
Great – soft tissue
Obstetrics
First trimester?
Conception to 12 weeks
Can do transvaginal 6 to 7 weeks
You get a 12 week scan
What is the purpose of a 12 week scan in obstetrics?
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
What can be seen in the first trimester – abnormalities?
 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

Twins – first trimester?
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
What is An embryonic pregnancy?
– pregnancy continues to develop despite the absence of a fetus
What is Nuchal translucency?
fluid at the back of neck – measure to determine risk of Down’s syndrome
What is Examphalos?
weakness of babies abdominal wall where umbilical cord joins – chromosome problem – contents potrude outside
The bigger it is the worse the prognosis
What is Gastroschisis?
defective abdominal wall - intestines are outside of the body
What is Ancephaly?
– malformation of large part of the brain/school/scalp is absent – incompatible with life
Second trimester:
13 to 26 weeks
Detailed anomaly scan at 20 weeks
The purpose of the details scanned 20 weeks:
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

Third trimester:
Checking for:
Growth – small/large for dates
placenta site
Presentation – position
Follow-up of abnormalities
Amniotic fluid volume
Doppler umbilical artery
what is placenta previa?
Cannot be fully digested till the third trimester
Vaginal delivery not possible

Placenta partially or completely covers the cervical opening
Umbilical artery Doppler:
Uteroplacental insufficiency - not enough oxygen
Intra-uterine growth resection
The liver:
Produces blood clotting stuff
Filters
Breaks down old or damaged blood cells And fat > energy 
Metabolic processes – creates energy
Liver – healthy versus damaged:
appearance
Healthy smooth
Fat deposits – bright
Fibrosis scar tissue
Cirrhosis - hard, lumpy, Chucky, unable to work
-Fluid around due to breakdown of cells
Lesions and mets:
All different some harder to find a pick up
Contrast enhanced ultrasound:
why?
what can it find
cost
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
Possible hepatic system problems
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
Vascular issues:
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

Doppler ultrasound?
Red - flowing towards the probe
Blue – flowing away from the probe
Kidney cancer clinic –
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
Urinary bladder scanner
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
Gynaecology scanning:
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
Fertility treatment:
Stimulate horrible to produce more focals
Suction needle that to pop focals there should be eggs and they are then take it out
Portable ultrasounds:
Renal, liver, DVT in ward
 covid lung
ECMO
What is it and what does it stand for?
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
Ultrasound MSK:
Commonly used in rheumatology and sports medicine
Steroid injections can be given under ultrasound control
Breast ultrasound:
For under 35-year-olds ultrasound is better
Simple cyst - acoustic enhancement
Testes and epididymi
Tumour hunting
Hernia
Weakness of war
Valsalva manoeuvre – used to increase pressure inside
Neonatal radio:
Used to assess intracranial haemorrhage and hydrocephalus
Baby hip ultrasound:
FAST scan:
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
