Practice exam Flashcards
An ABI of 0.6 indicates:
(a) mild disease
(b) moderate disease
(c) occlusive disease
(d) a technical aberration due to calcified arteries
(e) no detectable abnormality
(b) moderate disease
Over one you are fine less that one you are not fine
· Reductions in the resting ABI can be grouped as follows:
o mild 0.7-0.9
o Severe 0.5-.7
o rest pain 0.3-0.5
o critical ischemia <0.3
- A critical stenosis of the ICA is one which:
(a) is greater than 1/3 of the bulb diameter
(b) is greater than 90%
(c) affects the volume and pressure of arterial flow
(d) b & c
(e) is greater than 40%
(c) affects the volume and pressure of arterial flow
- To increase vascular resistance, which of the following must decrease
(a) pressure gradient
(b) vessel diameter
(c) vessel length
(d) Flow rate
(e) b & c
(b) vessel diameter
- Arteries supplying the sole of the foot are branches of
(a) posterior tibial artery
(b) medial malleolar artery
(c) anterior tibial artery
(d) plantar arterial arch
(e) peroneal artery
(a) posterior tibial artery
- Direct branches of the external carotid artery include which one of the following;
(a) ophalmic artery
(b) posterior cerebral artery
(c) superficial temporal
(d) supra -orbital artery
(e) frontal artery
(c) superficial temporal
- Aortic aneurysms that require stenting of the mesenteric arteries are?
(a) Saccular
(b) Infra renal
(c) Fusiform
(d) Supra renal
(e) Type A (dissection)
(b) Infra renal
- Which of the following best describes the Doppler effect?
(a) Frequency reduces as blood moves faster toward the transducer
(b) Frequency becomes louder as blood moves faster toward the transducer
(c) Frequency increases as blood moves faster toward the transducer
(d) Frequency increases as the angle of the beam approaches 90 degrees
(e) No sound is heard at 90 degrees
(c) Frequency increases as blood moves faster toward the transducer
- A below knee arterial bypass graft is most commonly constructed from
(a) goretex
(b) saphenous vein
(c) dacron
(d) radial artery
(e) giacomini vein
(b) saphenous vein
- An internal carotid artery occlusion may cause retrograde flow in the:
(a) External carotid artery
(b) Superior Thyroid artery
(c) Supra Orbital artery
(d) Vertebral artery
(e) All of the above
(c) Supra Orbital artery
- Renal transplant arteries are commonly anastomosed to the:
(a) aorta
(b) common iliac artery
(c) internal iliac artery
(d) hypogastric artery
(e) none of the above
(c) internal iliac artery
Describe the physical principles and ultrasound appearance of a:
(a) Mirror artifact
- displays objects on both sides of a strong reflector, though they are located only on one side of it.
- Eg the diaphragm, pleural surface, or aortic wall
- directs some of the echoes to a second reflector before it returns them to the transducer, resulting in a multipath reflection
- The resulting artifact shows up as the virtual object, deep to the original image but identical to it-thus the term ‘‘mirror.’’
- Mirror images may be produced with gray-scale, color, power, and spectral Doppler.
Describe the physical principles and ultrasound appearance of a: (b) Twinkle effect from renal calculi
· color Doppler signals that imitate motion or flow behind a stationary strongly reflecting interface
· can be seen behind any granular (irregular or rough) reflecting surface
· Twinkling artifact is believed to be caused by a narrow band of intrinsic machine noise called phase (or clock) jitter
· Similar to an acoustic shadow, twinkling does not occur 100% of the time
Using Poisuilles equation (assuming other variables remain constant), Describe the change in pressure in an artery: (a) if the radius is reduced (2 marks)
· P1 – P2 = 8ηLQ/ π r4 o Where o P1 – P2 : Tube Pressure difference o η: viscosity of the liquid o L: length of the tube o r: radius of the tube o Q: Flow in the tube (a) if the radius is reduced (2 marks) Pressure will increase by a factor of 4 meaning there will be higher resistance in the artery
Using Poisuilles equation (assuming other variables remain constant), Describe the change in pressure in an artery: (b) viscosity is reduced (2 marks)
(b) viscosity is reduced (2 marks) · P1 – P2 = 8ηLQ/ π r4 o Where o P1 – P2 : Tube Pressure difference o η: viscosity of the liquid o L: length of the tube o r: radius of the tube o Q: Flow in the tube If viscosity is decreased pressure is decreased as there is less resistance in the artery
Using Poisuilles equation (assuming other variables remain constant), Describe the change in pressure in an artery: (c) length is increased (2 marks)
(c) length is increased (2 marks) · P1 – P2 = 8ηLQ/ π r4 o Where o P1 – P2 : Tube Pressure difference o η: viscosity of the liquid o L: length of the tube o r: radius of the tube o Q: Flow in the tube If length is increased pressure is increased as there is more total resistance in the artery
- Describe the change in the appearance of the Spectral Doppler after
(a) changing the spectral map setting (2 marks)
Similar to b-mode map
Each map will change the way returning echoes are assigned to a brightness value
Map which gives the greatest contrast is most useful for vascular studies so that the spectral envelope can be measured with greater confidence
- Describe the change in the appearance of the Spectral Doppler after
(b) Increasing the gain (2 marks)
· it will not change the contrast of the spectral waveform but will help show a weak returning signal.
· increasing the gain will bring with it a level of spectral noise and the balance of noise to signal must be judged in each case
· excess gain fills in the tracing as low velocity echoes and mimics turbulent flow
- For a carotid artery velocity of 130cm/s,
a) state the range of stenosis consistent with this velocity (2 marks)
50-69%
<125cm/s is <50%
- For a carotid artery velocity of 130cm/s,
b) three features of the plaque which would make it more likely to produce symptoms (3marks)
Less echogenic than the surrounding muscle or absent B-mode texture (echolucent) with a thin fibrous cap.
Irregular
heterogenous