M103 T1 ultrasound Flashcards
How does ultrasound work?
by transmitting high-frequency sound waves through tissue
What does a transducer do?
emits sound-waves
What causes echoes?
sudden changes in tissue density or at a tissue interface (e.g. between muscle and bone)
How are echoes used to make an image?
echoes are detected by a transducer
the delay and intensity of these echoes can be used to construct an image
What colour does fluid and air appear on the xray image?
f & a - black
What colour do boney surfaces appear on the image?
bright
What colour do muscles and the viscera appear on xrays?
a mid-grey appearance
What does an orientation marker on the probe indicate?
which way the probe should be held
Where does an orientation marker on the probe usually point to?
the right side of the patient
During cardiac ultrasound where does an orientation marker on the probe point to?
the left side of the patient
Which three pathologies are Point of Care Ultrasounds used to assess?
Pulmonary oedema
Pleural effusion
Pneumothorax
What are the three main types of transducers? (CLiP)
curvilinear array
linear array
phased array
What are the pros and cons of using a linear array when taking an ultrasound?
provides a high resolution image
only up to about three cm of depth+
not able to take images of the heart
When are linear arrays used to take an ultrasound?
when looking at vascular or musculoskeletal structures
What do curvilinear and phased arrays have in common?
can produce images of deeper structures
have sector fields of view
What are the pros and cons of using a phase array when taking an ultrasound?
has a larger coverage area than single-probe methods - allows technicians to scan more at once, reducing the amount of time needed for inspections
expensive
operation and data interpretation are more difficult
can be greater difficulty in achieving good ultrasonic coupling due to the larger probe dimensions
When might phase array be used instead of curvilinear array and why?
phase array has a small footprint - the area of the ultrasound probe that would actually be contacting the skin, so can get in those intercostal spaces
curvilinear images will have more interference from the ribs than when using phase
Where might curvilinear array be used?
abdomen
thorax
Where might linear array be used?
pectoralis muscles
What are the borders of the safe triangle?
lateral edge of the pectoralis major - LPMA
lateral border of the latissimus dorsi - LLD
inferiorly - 5is
superiorly - base of the axilla
How do you find the base of the axilla?
join the lines between the pectoralis major and the latissimus dorsi
