Exam (elaborations)
ARDMS RVT URR QA, SAFETY & SPI QUESTIONS AND ANSWERS WITH SOLUTIONS 2024
- Module
- Institution
ARDMS RVT URR QA, SAFETY & SPI QUESTIONS AND ANSWERS WITH SOLUTIONS 2024
[Show more]
Seller
Follow
Performance
Reviews received
Content preview
ARDMS RVT URR QA, SAFETY & SPI QUESTIONS AND ANSWE RS WITH SOLUTIONS 2024 Which the following describes why there is no aliasing on CW doppler? A. the PW transducer uses a single element and the CW transducer uses two elements B. CW doppler does not require a sample volume to produce a doppler waveform C. CW doppler does not require beam steering to produce a doppler waveform D. CW probes are always lower frequency than PW probes - ANSWER A. the PW tx uses a single element and the CW tx uses two elements CW doppler uses separate elements for sending and receiving the sound waves. This allows for doppler evaluation without depth limitations. According to the Appropriate Use Criteria, which of the following is an inappropriate indication for a duplex exam on a hemodialysis fistula? A. inability to cannulate at dialysis B. ipsilateral arm swelling C. palpable thrill at the fistula site D. 1 month follow up baseline exam post -intervention - ANSWER C. palpable thrill at fistula site Hemodialysis fistulas and grafts will normally demonstrate a thrill over the connection site in the arm. Absence of the thrill ca indicate an occlusion of the fistula/graft. 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. velocities will be increased compared to last years exam B. 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 C. 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 D. velocities will be reduces compared to last years exam - ANSWER A. velocities will be increased compared to last years exam As the cursor angle increases, the angle between the bean and the flow decreases. As the angle between the bean and the flow decreases, the doppler shift increases (the more aligned the cursor is to the flow direction, the higher the doppler shift). EX: in creasing the cursor angle from 45 to 60 degrees = decreased angle between the bean and the flow = increased doppler shift and velocity. EX: decreasing the cursor angle from60 to 45 degrees = increased angle between the beam and the flow = decreased doppler shift and velocity. Overestimating the angle between the bean and the blood flow = overestimated flow velocity Underestimating the angle between the beam and the blood flow = underestimated flow velocity. 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 negative predictive value of the exam? A. increase by 4.5% B. decrease by 4.5% C. no effect on the negative predictive value, only affects accuracy D. decrease will vary with patient population - ANSWER D. decrease will vary with patient population 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 increase d amount of patients that have a lower velocity but truly demonstrate >60% stenosis in the renal artery. This positive predictive value will increase for the renal doppler exam because more patients will actually have significant stenosis when their exam p roduces velocities above 225cm/s. In order to validate test results, 450 patients underwent Angiography and a renal artery duplex exam to evaluate patients for renal artery stenosis. 300 arteries were correctly diagnosed as having normal flow or negative for renal artery stenosis. 100 arte ries were correctly diagnosed as having a stenosis present or positive 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 specificity of the renal artery duplex exam for this group of patients? A. 100/135 = 74% B. 300/315 = 95% C. 100/115 = 87% D. 300/335 = 90% - ANSWER D. 300/335 = 90% The specificity of a test is calculated by the number of correctly diagnosed exams (300) divided by the total number of true negative exams (300+35)The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Performance. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £10.96. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
75323 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now