If a renal artery Doppler exam demonstrates normal flow, but stenosis is identified on angiography evaluation, the US results are described as:
a.) False
... [Show More] negative
b.) False positive
c.) True negative
d.) True positive
a.) False negative
What information from an angiography report can be correlated with the ultrasound results?
a.) Diameter stenosis
b.) Areas of turbulent flow
C.) Area stenosis
D.) Flow velocity
a.) Diameter stenosis
*Angiography provides information on diameter stenosis of an artery, it is limited in that it can only estimate diameter stenosis (NOT AREA STENOSIS), and does not offer information on flow velocity, and cannon demonstrate areas of turbulent flow
A research project produced 16 true positive results and 4 false positive results along with 24 true negative and 6 false negative results from the total of 50 patients evaluated. What is the negative predictive value of the exam technique?
80%
*NPV is used to predict how often a negative study is truly negative. TN/TN+FN = 24/24 + 6 = 30 or 0.80/80%
Which of the following explains why a patient can receive an US diagnosis of 70% ICA stenosis, but an angiography diagnosis of 50% ICA stenosis?
a.) There was most likely a difference in the patients cardiac output on the dates the two exams were performed
b.) Angiography only evaluates the longitudinal axis of vessels which can lead to over-or-under estimation of the stenosis
c.) Angiography calculates the area stenosis and the US exam offers the diameter stenosis
d.) The patient has severe hyperlipidemia with acute disease progression between the two exams
b.) Angiography only evaluates the longitudinal axis of vessels, which can lead to an over-or-under estimation of the stenosis
_______________ is a radiology based exam utilizing iodinated dye to assess venous valvular competence
Descending venography
*Ascending venography uses contrast that is injected at the ankle and the course is followed up the leg to assess for DVT
What is the Framingham risk score?
A gender-specific criteria for estimation of 10 year risk of cardiovascular disease
Which venous flow is slow; echogenic particles can be seen near the walls and in the valvular sinus. This phenomenon is called:
a.) Virchow triad
b.) Misregistration artifact
c.) Clutter artifact
d.) Spontaneous contrast
d.) Spontaneous contrast
Which of the following is an appropriate indication for an extracranial arterial duplex exam?
a.) Screening exam on a patient with low Framingham risk scoring and no other assessment
b.) Hollenhorst plaque identified on retinal examination
c.) Follow up exam 6 months after initial diagnosis on patient with >50% ICA stenosis
d.) 3 month follow up to evaluate a carotid stent in stable patient
b.) Hollenhorst plaque identified on retinal examination
Which of the following causes an increase in the resistive index (RI) of the distal common carotid artery?
a.) Valsalva maneuver
b.) Proximal ICA stenosis
c.) Proximal CCA stenosis
d.) Aortic valve insufficiency
b.) Proximal ICA stenosis
*An occlusion of the ICA will lead to increased resistance to the flow in the ipsilateral common carotid artery.
Specificity
TN/(TN + FP)
Calculated by the number of correctly diagnosed negative exams, divided by the total number of true negative exams
Positive Predictive Value (PPV)
TP/(TP + FP)
The positive predicitve value is calculated by the number of correct positive diagnoses divided by the total number of positive diagnoses made
Which of the following describes the correct way to measure the resistive index for a renal artery waveform?
a.) Place a caliper at the onset of the systolic upstroke and at the true systolic peak
b.) Place a caliper at the true systolic peak and at the end diastolic velocity
c.) Place a caliper at the onset of the systolic upstroke and at the early systolic peak
d.) Place a caliper at the early systolic peak and the end diastolic velocity
b.) Place a caliper at the true systolic peak and at the end diastolic velocity
The recommended sample size for PW Doppler evaluation of an artery is?
1-1.5mm
What is the gold standard method of diagnosing temporal arteritis?
a.) CTA
b.) MRA
c.) Biopsy
d.) Duplex ultrasound
c.) Biopsy
*Biopsy of the temporal artery is the gold standard method of diagnosis for temporal arteritis
Pulsatility Index can be used to describe?
a.) The amount of blood vessel recoil
b.) The pressure gradient within a vessel
c.) The amount of variation in the velocity during the cardiac cycle
d.) Amount of turbulence within a vessel
c.) The amount of variation in the velocity during the cardiac cycle
*Higher resistance flow demonstrates higher PI values than low resistance flow.
According to the Appropriate Use Criteria, which of the following is an appropriate indication for a lower extremity venous duplex exam for venous insufficiency?
a.) Positive D-dimer test
b.) Telangiectasia
c.) Suspected or diagnosed pulmonary embolism
d.) Hyperpigmentation
d.) Hyperpigmentation
The Doppler tracing demonstrates electrical noise, how can you reduce or eliminate the artifact?
a.) Extend the cord to move the machine as far from the electrical outlet as possible
b.) Decrease wall filter settings
c.) Decrease the PRF
d.) Increase the wall filter settings
d.) Increase the wall filter settings
*Noise can be reduced by decreasing Doppler gain, increasing wall filter settings, or trying another wall outlet
Accuracy
(TP + TN)/(TP + TN + FP + FN)
The accuracy of a test is calculated by the total number of correct diagnoses, divided by the total number of diagnoses made. [Show Less]