class 4 (test 2)

Question 1

Early limitations to B-mode

Answer 1

Poor Quality
Color wasn’t available to clearly see lumen
Stenosis measurements change due to plane view
Calcium shadows
Velocity measurements more reliable than B-mode
Doppler became more accurate to measure velocities

Question 2

PW doppler purposes

Answer 2

Artery vs vein
hemodynamically sig obstruction
Grade severity of stenosis
Velocity changes over time
Velocities at locations throughout artery

Question 3

Pre-stenosis doppler

Answer 3

Probably normal
Waves taken in non-disease area
Doppler is high resistance only for very tight distal obstructions/occlusions

Question 4

No diastolic flow in CCA

Answer 4

indicates ICA occlusion

Question 5

No diastolic flow in P ICA

Answer 5

Indicates D ICA occlusion

Question 6

At-Stenoss doppler

Answer 6

when stenosis increases:
high velocities=high freq shift
>50%= psv 2x pre-stenosis
spectral broadening= non-laminar flow
may reverse flow under peak
high velocity extends into post-stenotic turbulence

Question 7

Hemodynamically significant stenosis

Answer 7

velocities increase dramatically at 50% diameter reduction or 75% area stenosis.
small diameter=high velocity
around 90% occlusion results in velocities coming back down