A patient is sent to your laboratory to have his lower extremity bypass graft evaluated with duplex.  While performing the examination you notice that the velocity at the proximal anastomosis is 80 cm/s.  You continue the examination and obtain a pulse wave Doppler signal about 1cm distal to the proximal anastomosis and you get a velocity of 210 cm/s.  What do these findings suggest? 

Difficulty in breathing, of which the individual is aware is known as ______. 

A hypertensive diabetic 65 year old male present for cerebrovascular testing because of an asymptomatic bruit on the right side.  You are considering all of the following to be potential sources of the bruit EXCEPT:

Which of the following is an anterior circulation symptom? 

A patient complains of temporary shading of the vision in one eye.  This symptom is called:

A sonographer switches to a higher frequency transducer.  What effect will that have on aliasing?

With CW Doppler, how many transducer elements are needed at a minimum? 

A long, brightly-echogenic streak is noted in the common femoral vein, which is otherwise patent and compressible.  It moves with probe compression and appears to move with venous flow.  This is most likely:

In one type of Doppler, mean velocity and direction of flow are displayed as a color.  What type of Doppler technique is this?

Most deep venous thrombi become established in the