Vascular Lab Flashcards
What are SVS guidelines for US measurement of the aorta?
Outerwall to outerwall
What does loss of respiratory variation and continuous flow in the common femoral veins indicate?
high grade IVC stenosis or caval occlusion
What is the maneuver for evaluation of popliteal artery entrapment?
Duplex of pedal vessels with with active plantar flexion
What does the SVS recommend for ultrasound measurement of the abdominal aorta?
Outer wall to outer wall
What is the axial resolution at the level of the aorta on ultrasound?
1-2mm
What are the risk factors for pseudoaneurysm development?
Female, obesity, calcified vessels, large sheaths, anticoagulation, and therapeutic rather than diagnostic
Where does do carotid body originate from and what do they do?
originate from neuro crest cells and monitor O2, pH, and Co2
What is the shamblin classification for carotid body tumors?
Class 1- small, can be dissection from adventitial plane
Class 2-partially surround the carotid artery
Classe 3-encircles the bifurcation
What nerves can carotid body tumors involve?
hypoglossal, glossopharyngeal, recurrent laryngeal, spinal accessory, or sympathetic chain
What are the findings in pseudoaneurysm?
ecchymosis, hematoma, pulsatile and painful mass, bruit, weakness or paresthesia secondary to nerve compression
What are the treatment options for pseudoaneurysms?
open repair, thrombin injection, ultrasound guided compression, stent placement, or coil embolization
What pseudoaneurysm factors make it more likely to be treated by thrombin injection?
small to medium size pseudoaneurysm with long narrow necks
What is the doppler shift equation?
Change in frequency = (2 x frequency x velocity of RBCs x cosine angle)/propagation speed of ultrasound in tissue
What duplex renal findings indicated >60% stenosis?
PSV 200 cm/sec or higher and ratio of 3.5 or greater. Aortic velocity has to be at least 50 cm/sec and in a non aneurysmal aorta
The penetration of intravascular ultrasound is…
Inversely proportional to ultrasound frequency. So the lower the frequency the deeper the penetration
Where are the blood pressure cuffs placed with 4 cuff segmental pressures?
Cuff at the ankle, proximal leg, above the knee thigh, and high thigh
What is the advantage of the four cuff technique?
evaluation SFA stenosis
How do you start the measurements with segmental pressures?
Start from distal to proximal
What is the provocative maneuver for evaluating TOS
arm abduction at 170 degrees with complete loss of arterial flow
Is cystic adventitial disease more prevalent in men or women?
5:1 in men
What sign do you see with cystic adventitial disease that is eccentric vs concentric?
scimitar sign for eccentric and hour glass sign with concentric
What are the criteria for iliac artery restenosis?
Velocity > 200 cm/sec, PSV ratio of >2, monophasic CFA waveform, decreased in ABI >0.15 and recurrence of claudication symptoms
What studies have comparable accuracy of detecting
>60% renal artery stenosis?
CTA and duplex
What renal artery duplex findings would make one consider intervention for renal artery stenosis?
RRI
How is the renal resistive index measured?
(PSV-EDV) / PSV of interlobular vessels of kidney
What arteries are studied on the transtemporal window?
The middle, anterior, and posterior cerebral arteries and the intracranial ICA
At what depth is the middle cerebral artery visualized on transtemporal doppler and which way is the flow going?
30-60mm and antegrade
At what depth is the terminal internal carotid artery visualized on transtemporal doppler and which way is the flow going?
55-65 mm and bidirectional flow
At what depth is the anterior cerebral artery visualized on transtemporal doppler and which way is the flow going?
60-80mm and retrograde
At what depth is the posterior cerebral artery visualized on transtemporal doppler and which way is the flow going?
60-70 mm and antegrade
What is normal velocity in the intracranial vessels?
60 cm/sec
Treadmill testing is more positive in what kind of patients?
Those with aortoiliac disease
Why is treadmill testing ineffective in infrapopliteal disease?
Because the sural branches to the gastroc come off at or above this level.
What does retrograde vertebral artery flow suggest?
innomminate or subclavian artery stenosis
What does flow reversal in diastole in the vertebral artery after exercise suggests what?
Subclavian steal syndrome
What are low resistance circulations in the body that would have persistence of flow throughout diastole?
The brain, kidneys, spleen, liver
What kind of waveform would a ICA dissection have?
to and fro
What kind of flow would the SMA have after a meal
High resistant flow with flow throughout diastole
What is the Nyquist limit?
The upper limit of the doppler shift frequency that can be accurately detected. Defined as PRF/2
How to prevent aliasing on spectral waveform?
increase pulse repetition frequency
Why should doppler angles greater than 60 degrees be avoided?
The cosine function changes more rapidly at larger angles
What is the formula for blood flow velocity?
V= (Doppler shift x propagation speed of utlrasound)/(2x Fxcostheta)
What is a mirror-image artifact?
Image findings of a struct that exists on one side of a strong reflector as also being present on the other side of the reflector due to reverberation
Where do you typically have mirror-image artifact?
Common around pleura and the diaphragm because of air-filled lungs
What happens with refraction artifact?
Ultrasound passing through tissues with different propagation speeds and causes a structure to be improperly positioned laterally in an ultrasound image.
What is the recommended surveillance interval for AAA of 3-3.9cm, 4-4.4 cm, and 4.5-5.4 cm for a
3 years, 2 years, and 1 year respectively
