RPVI Exam Vascular Physics Case Review.pdf - VascularWeb

RPVI TM 

Exam 

Vascular Physics Case Review 

Frank R. Miele 

I have nothing to disclose!

Exam Overview: According to Outline 

I. Instrumentation and Ultrasound Physics (12-18%) 

A. Doppler equation 

B. Continuous-wave/Pulsed wave Doppler 

C. Spectral waveform analysis 

D. Color/Power Doppler 

E. B-mode imaging 

F. Artifacts 

VIII. Quality Assurance and Ultrasound Safety (2-8%) 

A. Test validation 

B. Bioeffects of ultrasound

General Exam Info: 

• There were 201questions 

• 196 questions counted 

• Passing was 122 Questions (62%) 

• There were many image and video 

(loop) based questions 

Topic # Q’s % 

Instr & Physics 58 28.9% 

Extracranial C 44 21.9% 

Intracranial 6 3.0% 

P Ven (Upper & Low) 32 15.9% 

P. Art (Upper & Low) 26 12.9% 

Visc Vasc 16 8.0% 

Special Testing 13 6.5% 

Q & A 6 3.0% 

Total 201 

• At least 3 Q’s: Color direction (with cineloop) 

• At least 4 Q’s involving Doppler equation 

• Lots of Q’s on Wavelength 

• Lots of Q’s on Transducers 

• Questions on aliasing in PW 

• Couple of power and time questions 

• 3 statistics (was not given table) Had to calculate on one.

Lecture Format 

I. Quiz Questions (subdivided by topic) 

II. 

Quiz answers and explanations (subdivided by topic) 

Quiz Scoring: 

• 3 points for each correct 

• 4 points for each correct foundational question 

• (max = 94 points) 

• Approximately 75% (score of 71) would be considered passing 

CME: www.VascularWeb.org

PREPARING FOR THE RPVI EXAM 

RPVI eCourses 

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Doppler Equation 

QUESTIONS

Q1: Foundational Question 

Which of the following would not result in higher 

Doppler frequency shift 

A. Measuring flow velocity distal to a bend in the vessel 

B. Measuring the flow velocity slightly distal to a non flow reducing stenosis 

C. Using a Doppler angle of 50 degrees instead of 60 degrees 

D. Switching from a 6 MHz to a 4 MHz Doppler transmit frequency


Between what angles does the cosine change 

fastest 

A. 0 and 10 degrees 

B. 60 and 70 degrees 

C. 90 and 100 degrees 

D. 135 and 145 degrees 

E. All of the choices represent the same change

Q3: Question 

With respect to performing Doppler which statement 

is true regarding using a lower operating frequency 

A. the amount of scattering increases, making the blood easier to visualize 

directly. 

B. with the exception of shallow imaging, the sensitivity is significantly 

improved. 

C. aliasing becomes more likely. 

D. the peak velocity measurement accuracy degrades.

Q4: Doppler Angle 

Which of the following Doppler insonification angles would result in the 

greatest Doppler frequency shift 

A) 30 

B) 60 

C) 10 

 

 

 

D) 90 

 

E) 180


ANSWERS


Knowing the Doppler equation is critical: 

where: 

f Dop 

= Doppler shifted frequency (relative to transmit frequency) 

f 0 

v 

c 

= transmit frequency 

= velocity of target through medium 

= speed of interrogating beam through medium 

(c = 1540 m/sec for sound in tissue.) 

cos(θ) = mathematical correction for angle effect 

θ 

= insonification angle (or angle to flow)

Doppler Equation

Doppler Equation: Relative Relationships 

f 

Dop 

= 

2 fv o cos( θ ) 

c 

f 

f 

f 

f 

Dop 

Dop 

Dop 

Dop 

∝ 

∝ 

∝ 

∝ 

v (blood velocity) 

f 

0 

cos 

(operating frequency) 

( θ ) 

1 (propagation velocity) 

c 

*The starting point for answering almost all Doppler questions is the 

Doppler equation. You should know this equation cold!

Doppler Theory (Angle) 

The angular affect on the Doppler shift can be determined from the unit 

circle and the cosine function. 

y No change in λ 

1 

90° 

Longer λ 

180° 

-1 0 

0° = 360° 

x 

1 

x 

Shorter λ 

-1 

270°

Cosines

Doppler Theory (Angle) 

It is useful to know the cosine of the basic angles: 

y 

90° 

1 

Cosine (0°) = 1 

Cosine (30°) = 0.86 

Cosine (45°) = 0.707 

Cosine (60°) = 0.5 

Cosine (90°) = 0 

Cosine (180°) = -1 

180° 

-1 -.75 .-5 -.25 0 .25 .5 .75 

-1 -.75 .-5 -.25 0 .25 .5 .75 

270° 

60° 

45° 

30° 

1 

0° = 360° 

x

The Optimal Frequency for Doppler 

Recall the Scattering paradox: 

There is a tradeoff between increased reflectivity and increased 

absorption with a shorter wavelength from higher frequency operation. 

Notice that as the depth increases beyond 3 cm, the transmit frequency 

really should be set as low as possible for optimal sensitivity because of 

the dominance of absorption.

Q1: Foundational Answer 

Which of the following would not result in higher 

Doppler frequency shift 

A. Measuring flow velocity distal to a bend in the vessel 

B. Measuring the flow velocity slightly distal to a non flow reducing stenosis 

C. Using a Doppler angle of 50 degrees instead of 60 degrees 

D. Switching from a 6 MHz to a 4 MHz Doppler transmit frequency


Between what angles does the cosine change fastest 

A. 0 and 10 degrees 

B. 60 and 70 degrees 

C. 90 and 100 degrees 

D. 135 and 145 degrees 

E. All of the choices represent the same change

Q3: Answer 

With respect to performing Doppler which statement 

is true regarding using a lower operating frequency 

A. the amount of scattering increases, making the blood easier to visualize 

directly. 

B. with the exception of shallow imaging, the sensitivity is significantly 

improved. 

C. aliasing becomes more likely. 

D. the peak velocity measurement accuracy degrades.

Q4: Answer 

Which of the following Doppler insonification angles would result in the 

greatest Doppler frequency shift 

A) 30 

B) 60 

C) 10 

 

 

 

D) 90 

 

E) 180

Continuous/PW 

QUESTIONS


What is the main motivation for using pulsed waves 

in ultrasound 

A. Better ability to detect peak velocities 

B. Higher speeds of sound, implying faster imaging (higher frame rates) 

C. Perfect depth discrimination 

D. Better contrast resolution 

E. Some depth discrimination

Q6: Question 

If the Doppler sample rate (the PRF) is 8 kHz, at 

what frequency will the peak Doppler shift become 

undetectable 

A. 8 kHz 

B. 4 kHz 

C. 2 kHz 

D. 16 kHz

Q7: Question 

Aliasing is occurring with the Doppler spectrum from a stenosed artery. 

Which change would decrease the likelihood of aliasing occurring 

A) Decrease the transmit power 

B) Increase the Doppler spectral sweep speed 

C) Increase the PRF 

D) Increase the sample volume (gate) size 

E) Decrease the transmit (operating) frequency

Q8: Question 

Given the following situation, will aliasing occur 

f = 6 MHz f = 9.3 kHz PRF = 12 kHz 

o 

Dop 

A) Yes, always 

B) Yes sometimes 

C) No 

D) Cannot be determined

Q9: Question 


o 

Dop 

If the operating frequency is changed to 2 MHz, will aliasing occur 



C) No 


Continuous/PW 

ANSWERS

CW, Range Ambiguity, and Aliasing

CW: No Range Resolution (Animation)

Range Specificity: PW (Animation) 

Notice that the echoes from each of the three mountains return at distinct 

times such that each mountain is resolved (range resolution).

SPL and Ambiguity (Animation) 

In this case, the pulse length is so long that the echoes from mountain 1 

and mountain 2 overlap, making it impossible to distinguish mountain 1 

from mountain 2. The echo from mountain 3 is still distinct since the 

separation between mountain 2 and mountain 3 is greater than the 

separation between mountain 2 and mountain 1.

Nyquist

Nyquist and Doppler 

f 

Dop 

Dop (max) PRF 

f = 

2 

= 

⇒ 

⇒ 

⇒ 

2 fv∗ 

cos 

o 

( θ ) 

c 

Higher opertaing frequency 

Higher velocity 

Angles closer to 

 

0 or 180 

 

PRF 

1 1 

= = 

PRP ID( cm) ∗13μ 

sec 

⇒ Increasing Doppler Gate Depth


What is the main motivation for using pulsed waves 

in ultrasound 

A. Better ability to detect peak velocities 

B. Higher speeds of sound, implying faster imaging (higher frame rates) 

C. Perfect depth discrimination 

D. Better contrast resolution 

E. Some depth discrimination

Q6: Answer 

If the Doppler sample rate (the PRF) is 8 kHz, at 

what frequency will the peak Doppler shift become 

undetectable 

A. 8 kHz 

B. 4 kHz 

C. 2 kHz 

D. 16 kHz

Q7: Answer 

Aliasing is occurring with the Doppler spectrum from a stenosed artery. 

Which change would decrease the likelihood of aliasing occurring 

A) Decrease the transmit power 

B) Increase the Doppler spectral sweep speed 

C) Increase the PRF 

D) Increase the sample volume (gate) size 

E) Decrease the transmit (operating) frequency 

Note – Bonus points for recognizing both correct answers

Q8: Answer 

Given the following situation, will aliasing occur 


o 

Dop 

Yes: aliasing begins at 6 kHz 



C) No 


Q9: Answer 

If the operating frequency is change to 2 MHz, will aliasing occur 


o 

Dop 


o 

Dop 

No: Doppler shift is now less than 6 kHz 



C) No 


Spectral Waveform Analysis 

QUESTIONS

Q10: Question 

What is the true peak velocity 

A. 67.5 cm/s 

B. 50 cm/s 

C. 100 cm/s 

D. 135 cm/s 

Specified Angle = 40 degrees 

Actual Angle = 55 degrees 

PSV = 67.5 cm/sec

Q11: Question 

What is the primary difference between these two spectra 

A) “A” represents a proximal obstruction 

B) “B” represents a proximal obstruction 

C) “A” represents a higher distal resistance 

D) “B” represents a higher distal resistance 

E) None of the above. 

A 

B


What happens if you use a wall filter setting that is too low 

What happens if you use a wall filter setting that is too high

Spectral Waveform Analysis 

ANSWERS

Clutter “Signals” and Dynamic Range 

DNR human eye 

Fig. 20: (Pg 545) 

Can you think of some structures in the body which create large “clutter” signals

Applying the Wall Filter 

Fig. 21: (Pg 546)

Wall Filter Saturation 

Saturation appears on the spectrum as a bright white signal relatively 

symmetric about the baseline. In the following spectrum, the circuit 

saturates as the specular reflection from the valve is evident for each 

cardiac cycle

Wall Filter (Animation)

Typical Wall Filter Settings 

The following are typical wall filter settings for various applications: 

< 25 – 50 Hz Venous 

50 – 100 Hz Arterial 

200 – 600 Hz Adult Echo 

600 – 800 Hz Pediatric Echo 

The correct wall filter frequency to use depends on the operating 

frequency of the transducer as well as the velocity of the desired signal 

and the undesired clutter.

Q10: Answer 

A. 67.5 cm/s 

B. 50 cm/s 

C. 100 cm/s 

D. 135 cm/s 

Angle = 40 degrees 

True Angle = 55 degrees 

PSV = 67.5 cm/sec 

( 

 

) 

( 

 

) 

v 

cos 40 0.766 

* 67.5 / 90.2 / sec 

cos 55 

cm s ⎛ ⎞ 

= ∗ ⎜ = 

0.573 

⎟ 

⎝ ⎠ 

cm

Q11: Answer 

What is the primary difference between these two spectra 

A) “A” represents a proximal obstruction 

B) “B” represents a proximal obstruction 

C) “A” represents a higher distal resistance 

D) “B” represents a higher distal resistance 

E) None of the above. 

A 

B

Q12: Foundational Answers 

What happens if you use a wall filter setting that is too low 

Circuit saturation: Loud pops and bright white symmetric spikes in spectrum 

What happens if you use a wall filter setting that is too high 

Lower frequency shifts (velocity) signals can be eliminated

Color/Power Doppler 

QUESTIONS

Q13: Question 

Which of the following changes would most improve temporal 

resolution 

A. Decrease the color box width by 25% 

B. Decrease the 2D reference image by 50% 

C. Decrease the Color box depth by 25% 

D. Decrease the color packet size from 10 to 8 lines 

E. Decrease the color line density by 20%

Q14: Question 

In which Direction is the flow going 

A 

B 

C 

D 

• Fig. 54: (Pg 576) 

Cannot be determined 

E

Q15: Question 

In which direction is the flow 

A 

B 

C 

D 


E

Q16: Question 

Flow Direction 

A 

B 

C 

D 


E

Q17: Question 

A 

B 

C 

D 

• (Pg 580 E) 


E

Q18: Question 

Regarding the following image, which of the following statements is not 

true 

A) Flow direction cannot be 

determined 

B) This technique is less sensitive to 

angle than standard color Doppler 

C) If color were used instead there 

would likely be a region of flow 

dropout 

D) This technique is generally pretty 

sensitive to low flow 

E) The different color hues represent 

different velocities

Color/Power Doppler 

ANSWERS

How Images are Produced & Transducers

*Note that not all systems have separate wall filter controls for color 

Doppler. Usually the wall filters are set as a percentage of the 

color scale setting. 

Interpreting The Color Bar 

The color bar can be compared with the format of the Doppler 

spectrum. The color bar presents both flow directionality and average 

flow velocities (or frequency shifts). As with spectral Doppler, the 

baseline represents no flow detected. Aliasing results in a “wrapping” 

of the colors around the baseline. 

Fig. 49: (Pg 573)

Identifying the Doppler (Insonification) Angle 

The Doppler insonification angle is always measured between the 

direction of the flow and the line of observation (Doppler steered 

line).

Doppler Insonification Angle = 0° 

The flow is directly toward the transducer, so the angle between 

the flow direction and the steered line is 0 degrees. The 

resulting Doppler shift is positive.


The flow is directly away from the transducer, so the angle 

between the flow direction and the steered line is 180 degrees. 

The resulting Doppler shift is negative.


The angle formed between the flow direction and the steered Doppler line 

is 30 degrees. Notice how the flow is traveling closer to the transducer, 

but not directly toward as when the angle was 0 degrees. As a result, less 

of the Doppler shift is detected at 30 degrees than at 0 degrees, but the 

shift is still positive.


The angle formed between the flow direction and the steered Doppler 

line is 90 degrees. Notice how at the point where the beam intersects 

the flow, the flow is not traveling closer or farther away from the 

transducer, resulting in no frequency shift.

Determining Flow Direction 

Like spectral Doppler, the color direction is easily determined by 

analyzing the angle formed between the steered beam and the flow 

direction. 

+ V, + f Dop 

Angle less 

than 90º 


- V, - f Dop 

Steer 

Direction 

Direction chosen correctly 

Direction chosen 

incorrectly 

* The angle to flow is always measured between the steered beam 

direction and the head of the flow (where the flow is going to)

Q14: Answer 

A 

B 

C 

D 


E

Q15: Answer 


A 

B 

C 

D 


E

Q15: Continued 


A 

B 

C 

D 


E

Determining Flow Direction 

For the given color scale, when the angle between the head of the flow 

and the steered beam direction is less than 90 degrees, the flow is 

colored with hues of blue through aqua.

Q16: Answer 


A 

B 

C 

D 


E

Q17: Answer 

A 

B 

C 

D 

• (Pg 580 E) 


E

Q18: Answer 

Regarding the following image, which of the following statements is not 

true 

A) Flow direction cannot be 

determined 

B) This technique is less sensitive to 

angle than standard color Doppler 

C) If color were used instead there 

would likely be a region of flow 

dropout 

D) This technique is generally pretty 

sensitive to low flow 

E) The different color hues represent 

different velocities

B-Mode Imaging 

QUESTIONS


A typical wavelength in diagnostic ultrasound is: 

A) 300 micrometers 

B) 30 micrometers 

C) 300 millimeters 

D) 30 millimeters 

E) 30 nanometers

Q20: Question 

Higher frequency imaging results in better resolution because: 

A) there is better penetration. 

B) the wavelength is shorter. 

C) higher intensities can be used. 

D) the beams can be wider. 

E) more than one of the above is true.

Q21: Question 

Which of the listed mediums has the greatest 

absorption rate 

A. Bone 

B. Tendon 

C. Muscle 

D. Blood 

E. Fat

Q22: Question 

Which ultrasound modality has the worst temporal 

resolution 

A. CW Doppler 

B. PW Doppler 

C. B-Mode 

D. Color Doppler 

E. A-Mode

Q23: Question 

With the system controls set as show below, what 

will the image look like 

A. Appropriately gained 

B. Too bright in the near field 

C. Too bright in the far field 

D. Too dark in the near field 

E. Too dark in the far field 

Fig. 30: (Pg 328)


Compression is necessary: 

A. To reduce the dynamic range of the signal 

B. To decrease the range of frequencies in the signal 

C. To improve the signal to noise ratio 

D. To decrease the risk of bioeffects

Q25: Question 

Which statement about harmonic imaging is not 

true 

A. The second harmonic of 2 MHz is 4 MHz. 

B. Harmonic imaging generally results in less clutter artifacts in the image. 

C. Axial resolution usually gets better with harmonic imaging. 

D. Lateral resolution usually gets better with harmonic imaging. 

E. Harmonic imaging results in less penetration that fundamental imaging.

B-Mode Imaging 

ANSWERS

Wavelength Equation


A typical wavelength in diagnostic ultrasound is: 

A) 300 micrometers 

B) 30 micrometers 

C) 300 millimeters 

D) 30 millimeters 

E) 30 nanometers 

From the wavelength equation, using 10 MHz as the upper frequency and 2.5 

MHz as the lower, it can be shown that typical wavelengths range from 154 

micrometers to 616 micrometers. Only choice A falls in that range.

Q20: Answer 

Higher frequency imaging results in better resolution because: 

A) there is better penetration. 

B) the wavelength is shorter. 

C) higher intensities can be used. 

D) the beams can be wider. 

E) more than one of the above is true.

Q21: Answer 

Which of the listed mediums has the greatest 

absorption rate 

A. Bone 

B. Tendon 

C. Muscle 

D. Blood 

E. Fat

Q22: Answer 

Which ultrasound modality has the worst temporal 

resolution 

A. CW Doppler 

B. PW Doppler 

C. B-Mode 

D. Color Doppler 

E. A-Mode

Q23: Answer 

A. Appropriately gained 

B. Too bright in the near field 

C. Too bright in the far field 

D. Too dark in the near field 

E. Too dark in the far field


Compression is necessary: 

A. To reduce the dynamic range of the signal 

B. To decrease the range of frequencies in the signal 

C. To improve the signal to noise ratio 

D. To decrease the risk of bioeffects

Q25: Answer 

Which statement about harmonic imaging is not true 

A. The second harmonic of 2 MHz is 4 MHz. 

B. Harmonic imaging generally results in less clutter artifacts in the image. 

C. Axial resolution usually gets better with harmonic imaging. 

D. Lateral resolution usually gets better with harmonic imaging. 

E. Harmonic imaging results in less penetration that fundamental imaging.

Q&A: Test Validation 

QUESTIONS


With respect to statistical test validation and classification of test results 

as true positive, false positive, true negative, or false negative, the 

assumption is that 

A) the gold standard, although not perfect, is good enough. 

B) that the test is not as good as the gold standard. 

C) that the gold standard is perfect. 

D) that the gold standard is not as good as the test. 

E) There are more false results than true results.

Q27: Question 

Scary hospital vascular lab is validating their testing procedure predicting 

common carotid artery disease. The following results were obtained relative to 

the “gold standard”: 

‣ For the 71 times the test predicted disease, the test matched the gold 

standard 51 times. 

‣ For the 179 times the test predicted no disease, the test matched the gold 

standard 160 times 

Of the patients who were tested, how many have disease 

A) 160 

B) 71 

C) 70 

D) 51 

E) 20

Q28: Question 








For this test, statistically which is most likely 

A) to claim that a patient does not have disease when they do 

B) to be incorrect when positive for disease 

C) To incorrectly claim that a patient has disease when they do not 

D) To be incorrect when negative for disease

Q29: Question 

For a given test, the PPV is 81% the NPV is 88%, the sensitivity is 84% 

and the specificity is 90%, which statement is true regarding the overall 

accuracy. 

A) The accuracy must be > 90% 

B) The accuracy must be between 81% and 88% 

C) The accuracy must be between 84% and 90% 

D) The accuracy must be < 81% 

E) The accuracy must be between 84% and 88%

Q&A: Test Validation 

ANSWERS

Statistical Validation


With respect to statistical test validation and classification of test results 

as true positive, false positive, true negative, or false negative, the 

assumption is that 

A) the gold standard, although not perfect, is good enough. 

B) that the test is not as good as the gold standard. 

C) that the gold standard is perfect. 

D) that the gold standard is not as good as the test. 

E) There are more false results than true results.

Q27: Answer 








Of the patients who were tested, how many have disease 

A) 160 

B) 71 

C) 70 

D) 51 

E) 20 

Comparison Test 

+ 

_ 

(TP) 

Gold Standard 

_ 

+ 

51 

(FN) 

19 

(FP) 

20 

(TN) 

160

Q28: Answer 

For this test, statistically which is most likely 

A) Claim that a patient does not have disease when they do -- (SENSITIVITY) 

B) To be incorrect when positive for disease -- (PPV) 

C) Claim that a patient has disease when they do not – (SPECIFICITY) 

D) To be incorrect when negative for disease -- (NPV) 

Gold Standard 

_ 

+ 

Comparison Test 

+ 

_ 

(TP) 

51 

(FN) 

19 

(FP) 

20 

(TN) 

160

Q29: Answer 

For a given test, the PPV is 81% the NPV is 88%, the sensitivity is 84% 

and the specificity is 90%, which statement is true regarding the overall 

accuracy. 

A) The accuracy must be > 90% 

B) The accuracy must be between 81% and 88% 

C) The accuracy must be between 84% and 90% 

D) The accuracy must be < 81% 

E) The accuracy must be between 84% and 88%

PREPARING FOR THE RPVI EXAM 

RPVI eCourses 

RPVI Exam Sims 

Go Online: SVU, SVS, or www.PegasusLectures.com

RPVI eCourse (Modules)

RPVI Exam Sims

END REVIEW 

Frank R. Miele 

President and Founder 

Pegasus Lectures, Inc. 

FMiele@PegasusLectures.com

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