Ultrasonography Flashcards
what is ultrasound?
sound waves with frequencies higher than the human audible range, upper limit is 20kHz
what is the pulse echo principle?
- ultrasound probe emits sound waves & then receive echoes from the original wave
- when it passes through tissue boundary, can be reflected back or will pass through & continue propagating
- adjacent tissues with varying densities will reflect more of the sound waves, e.g. air and lungs
fluid in ultrasound
dark
bone/gas in ultrasound
white
soft tissue in ultrasound
grey
uses of ultrasound
- widely accessible
- results can be seen immediately; bedside
- ‘real time’ imaging
- usually non invasive
- no documented side effects in humans
- no radiation
disadvantages of ultrasound
- training is resource intensive
- effectiveness & accuracy is operator dependent
12 week obstetrics scan
- first scan offered to low risk pregnancies
- detects viability, no. of fetes’s, abnormalities, morphology of ovaries, gestational age of fetus
downs syndrome screening
fetal nuchal translucency uses ultrasound to measure the size of the nuchal pad at the nape of fetal
20 week obstetrics scan
identify abnormalities which could indicate life-threatening condition, e.g. spina bifida
- placenta localisation
- fetal biometry
- fibroid monitoring
achondroplasia
20 week scan abnormality
- bowing of long bones
- thickened soft tissue surrounding long bones
low lying placenta
20 week scan abnormality
- measure the distance from the lowest edge of the placenta to the internal os of the cervix
- if placenta is too close closer to the due date, may need a C-section
talipes (club foot)
20 week scan abnormality
- can see foot turned up
Anhydraminos
Anhydramnios is a condition affecting pregnant women in which there is no amniotic fluid surrounding the fetus.
Polyhydraminos
Excess of amniotic fluid in the amniotic sac
Umbilical Artery Doppler Assessment
Can be used to highlight the affects of pre-eclampsia and intrauterine growth restriction (IUGR)
Ectopic pregnancy
egg implanting outside of the uterine tube: ectopic pregnancy
severe pain & bleeding
Dichorionic
Twins that develop in separate sacs
Monochorionic
Twins sharing the same placenta
Fibroids
fibrous muscular tissue, many eventually grow until the
blood supply they receive can no longer support further growth, but others can get very large and require surgical interventions ( myomectomy / uterine
embolisation / hysterectomy)
Uterine polyps
Growths from the inner wall of the womb, could turn cancerous
which organs can the abdominal ultrasounds monitor?
liver, kidneys, aorta, pancreas, spleen, gallbladder
aortic screening
section of abdominal aorta is aneurysmal when reaching 3cm in diameter
gallstones
imbalance of chemical make up within bile in the gallbladder
urinary tract ultrasound
- polycystic kidney disease
- enlarged prostate
- renal calculi
testicular ultrasound
- varicocele: enlargement of veins in the scrotum
- hydrocele: fluid collects in the thin sheath surrounding the testicle
- testicular cancer
- simple cyst
breast ultrasound
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)
vascular DVT
ultrasound used to confirm the presence of DVT
musculo-skeletal ultrasound
- muscle/tendon tears
- inflammation
- cysts
- hernias
FAST
- point of care ultrasound
- undertaken at the time of the presentation of a trauma patient
