QA, Safety & SPI Flashcards
Which of the following correctly describes a gold standard test?
A. an accepted test that is assumed to be able to determine the true disease state of a patient, regardless of positive or negative test findings
B. a type of test that has been used for over 15 years to successfully diagnose rule out disease when it is absent
C. a type of test that has been used for over 15 years to successfully diagnose disease when it is present
D. a test that is preferred by most doctors to make a specific diagnosis
A
Gold Standard Testing refers to an accepted test that is assumed to be able to determine the true disease state of a patient regardless of positive or negative test findings or sensitivities or specificities of other diagnostic tests used. As new diagnostic methods become available, the “gold standard” test may change over time. For example, an aortogram used to be the gold standard test for the diagnosis of aortic dissection, but today MRA has become the new “gold standard” test for aortic dissection because it has the highest sensitivity and specificity levels.
Which of the following is a disadvantage of magnetic resonance angiography compared to Doppler evaluation of the carotid arteries?
A. MRA exams tend to overestimate the level of stenosis present
B. MRA of the carotid arteries can only be performed on patients who are not diabetic
C. contrast is always required for the exam
D. patients on anticoagulant therapy cannot undergo an MRA evaluation
A
MRA exams tend to overestimate the level of stenosis present when compared to Doppler findings. Contrast may be used on the exam but is not always required. Certain patients are at a higher risk of renal failure from the contrast.
The ability of PW Doppler to determine the \_\_\_\_\_\_\_\_\_\_\_ is the primary advantage over CW Doppler techniques. A. pulsatility of flow B. direction of flow C. location of stenosis in the vessel D. velocity of flow
C
CW Doppler provides no depth resolution during Doppler evaluation. CW Doppler is preferred for higher velocities and deeper flow evaluations. PW Doppler is able to provide velocity, pulsatility and location of a stenosis.
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 onset of the systolic upstroke and at the early systolic peak
C. place a caliper at the true systolic peak and the end diastolic velocity
D. place a caliper at the early systolic peak and the end diastolic velocity
C
Resistive index - place a caliper at the true systolic peak and the end diastolic velocity; Acceleration time - place a caliper at the onset of the systolic upstroke and at the early systolic peak
When the velocity of flow is calculated for vessels evaluated on a TCD exam, a \_\_\_\_\_\_\_\_ degree angle of incidence is assumed. A. 45 B. 0 C. 30 D. 60
B
When the velocity of flow is calculated for vessels evaluated on a TCD exam, a 0-degree angle of incidence is assumed.
If new research shows that the minimum velocity criteria used to diagnose >60% renal artery stenosis is actually 225cm/s, not 180cm/s, how will this affect the accuracy of the renal Doppler exam?
A. increase will vary with patient population
B. decrease will vary with patient population
C. increase by 4.5%
D. no effect on the accuracy, only affects positive and negative predictive value.
A
Negative predictive value refers to the ability of an exam to correctly predict the absence of disease. Raising the peak velocity required to identify a significant renal stenosis will decrease the negative predictive value. This occurs due to the increased amount of patients that have a lower velocity but truly demonstrate >60% stenosis in the renal artery. The positive predictive value will increase for the renal Doppler exam because more patients will actually have significant stenosis when their exam produces velocities above 225cm/s.
Accuracy will increase because of the increase in truly positive exams compared to the total number of exams. The more people correctly diagnosed as positive, the greater the accuracy of an exam.
According to the Appropriate Use Criteria, which of the following is an inappropriate indication for a duplex exam on a hemodialysis fistula?
A. ipsilateral arm swelling
B. inability to cannulate at dialysis
C. 1 month follow up baseline exam post-intervention
D. palpable thrill at the fistula site
D
Hemodialysis fistulas and grafts will normally demonstrate a thrill over the connection site in the arm. Absence of the thrill can indicate an occlusion of the fistula/graft.
Which of the following Doppler angles would lead to the most significant error in estimation of flow velocity? A. 25 B. 45 C. 65 D. 80
D
The greater the Doppler angle, the greater the amount of error in the calculated velocity.
Resistive Index is a ratio utilized to quantify which of the following? A. phasicity of flow B. resistance to flow C. flow velocity D. turbulence of flow
B
The resistive index compares the systolic and diastolic flow velocities to evaluate tissue resistance to blood flow.
If a carotid Doppler exam was performed last year with a Doppler angle of 45 degrees and the current exam was performed with a 60 degree angle. Assuming there has been no change in the level of stenosis, how will this affect the exam?
A. no change because the ultrasound system is programmed to always assume a 60 degree angle is used for each exam and uses this angle in the Doppler equation
B. no change because the ultrasound system is programmed to always assume a 0 degree angle is used for each exam and uses this angle in the Doppler equation
C. velocities will be reduced compared to last year’s exam
D. velocities will be increased compared to last year’s exam
D
As the cursor angle increases, the angle between the beam and the flow decreases. As the angle between the beam and the flow decreases, the Doppler shift increases (the more aligned the cursor is to the flow direction, the higher the Doppler shift).
EX: Increasing the cursor angle from 45 to 60 degrees = decreased angle between the beam and the flow = increased Doppler shift and velocity.
EX: Decreasing the cursor angle from 60 to 45 degrees = increased angle between the beam and the flow = decreased Doppler shift and velocity.
Overestimating the angle between the beam and the blood flow = overestimated flow velocity
Underestimating the angle between the beam and the blood flow = underestimated flow velocity
The recommended sample size for PW Doppler evaluation of an artery is? A. 1-1.5mm B. 3-4mm C. 0.5mm D. 0.5cm
A
Small sample sizes demonstrate a more specific location of the velocity detected.
When venous flow is slow, echogenic particles can be seen near the walls and in the valvular sinus. This phenomenon is called: A. spontaneous contrast B. misregistration artifact C. clutter artifact D. Virchow triad
A
Slow moving red blood cells around the valve leaflets and near the vein walls can be mildly reflective. This phenomenon is called spontaneous contrast.
What information from an angiography report can be correlated with the ultrasound results? A. flow velocity B. diameter stenosis C. area stenosis D. areas of turbulent flow
B
Angiography provides information on diameter stenosis of an artery. It is limited in that it can only estimate diameter stenosis (no area stenosis), does not offer information on flow velocity, and cannot demonstrate areas of turbulent flow.
Abdominal Doppler exams are usually best performed with a frequency of \_\_\_\_\_\_MHz and lower extremity arterial duplex exams are usually best performed with a frequency of \_\_\_\_\_\_\_\_MHz. A. 2-4MHz, 8-10MHz B. 1-3MHz, 5-7MHz C. 2-4MHz, 5-7MHz D. 5-7MHz, 8-10MHz
C
Abdominal Doppler exams are usually best performed with a frequency of 2-4MHz and Lower Extremity Arterial Duplex exams are usually best performed with a frequency of 5-7MHz.
Which of the following describes the correct way to measure the acceleration time for a renal artery waveform?
A. place a caliper at the true systolic peak and the end diastolic velocity
B. place a caliper at the early systolic peak and 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 onset of the systolic upstroke and at the true systolic peak
C
Resistive Index - place a caliper at the true systolic peak and the end diastolic velocity.
Acceleration Time - place a caliper at the onset of the systolic upstroke and at the early systolic peak.
In order to validate test results, 450 patients underwent Angiography and a Renal Artery Duplex exam to evaluate patients for renal artery stenosis. 100 arteries were correctly diagnosed as having a stenosis present or positive for renal artery stenosis. 35 arteries were incorrectly diagnosed with stenosis by ultrasound and 15 arteries were incorrectly diagnosed as negative for stenosis by ultrasound. What is the accuracy of the renal artery duplex exam for this group of patients? A. 400/415 = 96% B. 135/450 = 30% C. 400/435 = 92% D. 400/450 = 89%
D
The accuracy of a test is calculated by the total number of correct diagnoses (300 + 100) divided by the total number of diagnoses made (300 + 100 + 35 + 15).
When evaluating heavily calcified arteries, what system settings should be increased to improve the demonstration of flow in the vessels? A. velocity scale and persistence B. color gain and angle of insonation C. frequency and output power D. persistence and sensitivity
D
Arterial calcification can limit the 2D and color Doppler evaluation. To evaluate heavily calcified arteries use multiple imaging planes, increase color Doppler gain, increase sensitivity and persistence levels. These change is system settings should increase the amount of color displayed.
What is the gold standard evaluation technique for renal artery stenosis? A. Angiography B. MRA C. Ultrasound D. CTA
A
Which modality is preferred to diagnose an aortic dissection? A. CTA B. Angiography C. Duplex ultrasound D. MRI
A
CT scan is preferred for evaluation of AAA and dissection. The exam provides the best detail for the evaluation of aortic size and lumen characteristics. All portions of the aorta can be seen with CT. Ultrasound can be limited by bony anatomy.
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? A. 20% B. 40% C. 80% D. 95%
C
NPV is used to predict how often a negative study is truly negative. TN / TN + FN = 24 / 24 + 6 = 24 / 30 = 0.80 or 80%
Which of the following Doppler information is necessary to calculate the resistive index?
A. peak systolic velocity only
B. peak systolic velocity and end diastolic velocity
C. peak systolic velocity and peak diastolic velocity
D. peak systolic velocity, average flow velocity and end diastolic velocity
B
The resistive index = PSV - EDV / PSV
The Appropriate Use Criteria were developed:
A. while considering vascular ultrasound or physiologic testing by itself as a reasonable exam choice
B. to provide guidance for when to use vascular ultrasound as a secondary exam to confirm a diagnosis
C. by a collaboration of insurance companies seeking to streamline covered services
D. to identify physicians and facilities that need further education on ordering procedures
A
The Appropriate Use Criteria for vascular ultrasound and physiologic testing was developed through the collaboration of several vascular ultrasound and medical societies to improve efficiency and effectiveness of patient diagnosis and treatment. The most common indications given for vascular ultrasound and physiologic testing were scored for appropriate use. Not all exam indications were evaluated. The indications were scored while considering vascular ultrasound or physiologic testing by itself as a reasonable exam choice.
Three categories used to classify indications:
7-9 points: generally appropriate indication
4-6 points: may be appropriate or reasonable indication; situational consideration
1-3 points: inappropriate or unreasonable indication if there is more than one indication for an exam, the indication with the highest score should be used to determine appropriate use
When a patient has multiple indications, which one is used to determine appropriate use of vascular ultrasound testing?
A. all scores should be added together and divided by the number of indications
B. the indication with the lowest score should be used to determine appropriate use
C. the indication with the highest score should be used to determine appropriate use
D. if a patient has multiple symptoms, the Appropriate Use Criteria is invalid
C
If there is more than one indication for an exam, the indication with the highest score should be used to determine appropriate use.
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 sensitivity of the exam technique? A. not enough information given B. 27% C. 73% D. 50%
C
True positives / true positives + false negatives
16/16+6 = 0.73 x 100%
Which of the following parameters is displayed as the y-axis on a Doppler tracing? A. frequency shift B. speed C. time D. motion
A
Doppler shift frequencies are displayed on a tracing as a function of time; x axis = time, y axis = Doppler shift; Velocity could also be a correct answer, but speed is incorrect. Speed does not indicate the direction of the motion. Doppler evaluation provides the speed and direction of the flow = velocity.
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 pulsatility index (PI) can be used to describe the amount of variation in the velocity during the cardiac cycle. High 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 screening ankle-brachial index exam?
A. patient with low Framingham risk score
B. nocturnal pain or cramping with normal pulses on clinical exam
C. 58yr old male with diabetes
D. diabetic neuropathy with normal pulses
C
Dedicated ABI exams are recommended as a screening tool in patients with a femoral bruit or diminished pulses, patients >50yrs with diabetes or smoking history and all patients over 70yrs of age.
If a renal artery Doppler exam demonstrates normal flow, but stenosis is identified on angiography evaluation, the US results are described as: A. false negative B. true positive C. true negative D. false positive
A
If the current exam is negative but the gold standard is positive = false negative results on current exam.
If the current exam is positive but the gold standard is negative = false positive results on current exam.
If the current exam is negative and the gold standard is negative = true negative results on current exam.
If the current exam is positive and the gold standard is positive = true positive results on current exam.
According to the Appropriate Use Criteria, which of the following is an inappropriate indication for an upper extremity arterial duplex exam?
A. 1 month follow up baseline exam post-intervention
B. unilateral cold hand
C. unilateral arm swelling
D. suspected positional arterial obstruction
C
Limb swelling is a common symptom of extremity venous disease, not arterial disease.
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 positive predictive value of the exam technique? A. 20% B. 50% C. 80% D. 95%
C
The positive predictive value is calculated by the number of correct positive diagnoses (16) divided by the total number of positive diagnoses made (16 + 4) 16/20 = 0.80 or 80%.
Which of the following correctly describes the negative predictive value (NPV) of a testing technique?
A. if the test result is positive, NPV is the probability that the patient actually has the disease
B. the ability of a test to rule out disease when it IS NOT present
C. the ability of a test to detect disease when it IS present
D. if the test result is negative, NPV is the probability that the patient does not have disease
D
Negative Predictive Value: calculates how often a negative study is correctly diagnosed; if the test result is negative, NPV is the probability that the patient does not have disease.
Which of the following exams does not require angle corrected Doppler evaluation? A. aorta duplex B. IVC duplex C. renal artery duplex D. TIPS evaluation
B
Any Doppler exam that requires measurement of blood flow velocity requires angle correction to obtain an accurate velocity. This includes all arterial exams and TIPS evaluations. A duplex exam of the IVC is used to assess patency and flow variation with respiration and cardiac pulsatility. No velocity information is used in the IVC duplex exam.
According to the Appropriate Use Criteria, which of the following is an inappropriate indication for an aortic duplex exam?
A. 1 month follow up after endograft placement
B. fever of unknown origin
C. lower extremity claudication
D. pulsatile abdominal mass
B
Isolated findings of a fever of unknown origin is not an appropriate indication for any vascular ultrasound exam. It is a non-specific symptom that has rarely been associated with vascular disease. Unilateral lower extremity symptoms can be caused by iliac artery disease and bilateral symptoms can be related to aortic disease. A pulsatile abdominal mass is a clinical indication of AAA. If endograft placement is performed to treat an AAA, the baseline exam should be performed within 1 month of the procedure.
Which of the following correctly describes the positive predictive value (PPV) of a testing technique?
A. if the test result is negative, PPV is the probability that the patient does not have disease
B. if the test result is positive, PPV is the probability that the patient actually has the disease
C. the ability of a test to rule out disease when it IS NOT present
D. the ability of a test to detect disease when it IS present
B
Positive Predictive Value: calculates how often a positive study is correctly diagnosed; if the test result is positive, PPV is the probability that the patient actually has the disease.
