probe sends and recieves sound waves
probe measures amount and time taken for reflected sounds to return to gauge distance
fluid is not reflective = dark
bone very reflective = white
describing changes
- Anechoic (dark) fluid
- Iso/hypo/hyperechoic (soft tissue → fat)
- hyperechoic (bone and metal)
- shadowing (from hyperechoic area reflecting most, limiting further penetration)
- enhancement (after fluid filled area, concentrated sound reflection)
- doppler (shows direction and velocity through colour map)