Vascular duplex scanning of color flow imaging of lower and upper extremities ch 13 and 12

What is Doppler equation

2(V)(f)(cos theta) divided by prop speed (1540 m/s)

Why is there a 2 in the Doppler equation

Signal received and signal sent - sound striking RBC and RBC sending signal back to transducer

What pt position may be helpful to scan pop or tibioperoneal trunk

Prone or lateral decub

What transducer is used for LEA vascular

7-10 MHz (we use 12)

What mode should be used to evaluate presence, size, location, and characteristics of plaque

B-mode

What should you use to evaluate flow patterns

Spectral analysis and Color flow

What waveform should lower extremity arteries have

Triphasic

What frequency wave characteristics should arteries have

Narrow w/ no spectral broadening 

Will a stenosis have increased or decreased velocity

Increase

Long time occluded arteries are — to see

Often contracted and difficult

What is velocity ratio formula?

Stenotic PSV divided by pre-stenotic PV

What % stenosis is mild

1-19%; normal V, triphasic, small spectral broadening

What % stenosis is moderate

20-49%, increased PSV by 30-50% w/ spectral broadening, triphasic but reversed flow may be diminished

What % stenosis/diameter reduction is severe

50-99%, increased systolic velocity >100%, spectral broadening, monophasic waveform

Total occlusion demonstrates —-

No flow, possible systolic thumping heard prox to occlusion

What % diameter increase signifies an aneurysm in a native artery

50% (>3cm in aorta)

— % of Pseudo aneurysms thrombose spontaneously/close on it’s own

60%

What upper extremity arteries are typically affected by atherosclerosis

Subclavian or Axillary

What will be patient complaint be with UEA issues

Muscle Fatigue or pain with use, digit discoloration and temp sensitivity

Can raynaud’s be diagnosed with UEA scan

No

what is pt positioning for UEA scan

Supine with slightly elevated head, arm at 45 degrees

What transducer(s) should be used for UEA scan

5-7 mhz best for subclavian and axillary, can use 7-15 mhz for thin or lower arm veins

What is normal waveform for UEA

Triphasic

How will clenching of hand or movement alter UEA waveform

Will cause it to become more biphasic or monophasic due to hyperemia 

What is hypothenar hammer syndrome

Aneurysm of ulnar artery from using palm as a hammer

What is associated with subclavian aneurysms 

Embolization to digits

What is main use of duplex imaging in UEA 

Evaluation of Hemodialysis access/vein mapping