Echocardiography Board Review: 500 Multiple Choice Questions With Discussion

Chapter 4

Questions

1.  61. Volumetric flow rate decreases with an increase in:

1.  A. Pressure difference

2.  B. Vessel radius

3.  C. Vessel length

4.  D. Blood viscosity

5.  E. Vessel length and blood viscosity

2.  62. Which of the following on a color Doppler display is represented in real time?

1.  A. Gray-scale anatomy

2.  B. Flow direction

3.  C. Doppler spectrum

4.  D. Gray-scale anatomy and flow direction

5.  F. All of the above

3.  63. Approximately how many pulses are required to obtain one line of color Doppler information?

1.  A. 1

2.  B. 100

3.  C. 10

4.  D. 10 000

4.  64. Multiple focuses are not used in color Doppler imaging because:

1.  A. It would not improve the image

2.  B. Doppler transducers cannot focus

3.  C. Frame rates would be too low

4.  D. None of the above

5.  65. Widening the color box on the display will _________ the frame rate.

1.  A. Increase

2.  B. No change

3.  C. Decrease

4.  D. Cannot be determined

6.  66. The simplified Bernoulli equation is inapplicable under the following circumstances:

1.  A. Serial stenotic lesions

2.  B. Long, tubular lesions

3.  C. Both

4.  D. None of the above

7.  67. The Bernoulli equation is an example of:

1.  A. Law of conservation of mass

2.  B. Law of conservation of energy

3.  C. Law of conservation of momentum

4.  D. None of the above

8.  68. The continuity equation is an example of:

1.  A. Law of conservation of mass

2.  B. Law of conservation of energy

3.  C. Law of conservation of momentum

4.  D. None of the above

9.  69. Effective regurgitant orifice area by the proximal isovelocity surface area (PISA) method is an example of:

1.  A. Law of conservation of mass

2.  B. Law of conservation of energy

3.  C. Law of conservation of momentum

4.  D. None of the above

10. 70. Doppler calculation of aortic valve area is an example of:

1.  A. Law of conservation of mass

2.  B. Law of conservation of energy

3.  C. Law of conservation of momentum

4.  D. None of the above

11. 71. Calculation of right ventricular systolic pressure from the tricuspid regurgitation velocity signal is an example of:

1.  A. Law of conservation of mass

2.  B. Law of conservation of energy

3.  C. Law of conservation of momentum

4.  D. None of the above

12. 72. Color flow jet area of mitral regurgitation depends upon:

1.  A. Amount of regurgitation alone

2.  B. Driving pressure and the regurgitant volume

3.  C. Presence of aortic regurgitation

4.  D. Degree of mitral stenosis

13. 73. Factors influencing mitral regurgitation jet volume also include:

1.  A. Proximity of left atrial wall

2.  B. Heart rate

3.  C. Gain setting

4.  D. Filter setting

5.  E. Left atrial size

6.  F. All of the above

14. 74. Amount of mitral regurgitation depends upon:

1.  A. Regurgitant orifice size

2.  B. Driving pressure

3.  C. Duration of systole

4.  D. All of the above

15. 75. Hemodynamic impact of a given volumetric severity of mitral regurgitation (MR) is increased by:

1.  A. Nondilated left atrium

2.  B. Left ventricular hypertrophy

3.  C. Presence of concomitant aortic regurgitation

4.  D. All of the above

5.  E. None of the above

16. 76. Which feature is consistent with severe mitral regurgitation:

1.  A. Jet size to left atrial area ratio of 0.5

2.  B. The PISA radius of 1.2 cm at an aliasing velocity of 50 cm/s

3.  C. Effective regurgitant orifice area of 0.7 cm2

4.  D. All of the above

5.  E. None of the above

17. 77. When using a fixed-focus probe this parameter cannot be changed by the sonographer:

1.  A. Pulse repetition period

2.  B. Pulse repetition frequency

3.  C. Amplitude

4.  D. Wavelength

18. 78. The following signal was obtained from the apical view in a 45-year-old man with a systolic murmur. What is the most likely origin of this signal?c04g001

1.  A. Mitral valve prolapse with late systolic MR

2.  B. Rheumatic MR

3.  C. Hyperdynamic left ventricle with cavity obliteration

4.  D. Subaortic membrane

19. 79. Continuous wave signal from the apical view. The image is suggestive of:c04g002

1.  A. Moderate aortic stenosis

2.  B. Severe aortic stenosis

3.  C. Mitral regurgitation

4.  D. Prosthetic aortic valve obstruction

20. 80. The signal obtained from the right parasternal view is suggestive of:c04g003

1.  A. Severe MR

2.  B. Severe aortic stenosis

3.  C. Severe aortic regurgitation

4.  D. Severe pulmonary stenosis

Answers for chapter 4

1.  61. Answer: E.

Volume flow rate = pressure difference × π × diameter4/128 × length × viscosity. Hence with an increase in length and viscosity, the volume flow rate will decrease. An increase in driving pressure and radius will increase the flow rate. Also, flow rate = pressure difference/resistance or pressure difference = flow rate x resistance (similar to Ohm's law of electricity).

2.  62. Answer: D.

Both gray scale and flow direction are displayed in real time.

3.  63. Answer: C.

Color Doppler is a pulse Doppler technique, and velocities at multiple depths along the scan line are needed to construct color flow line. Using the multigate technique with placement of several sample volumes along the Doppler beam path, a 2D display of distribution of blood flow is generated. About 10 pulse packets are needed for each scan line of Color Doppler to obtain precise information as opposed to only one pulse packet to create one B mode scan line. Based on a propagation velocity of 1540 m/s, an echo signal reflected from a depth of 10 cm has a round trip time of 130 µs, which is the time required to generate a line of B mode scan. It takes 10 times longer, 1.3 ms to generate a color Doppler scan line.

4.  64. Answer: C.

Combination of multiple pulses needed for a scan line, multiple focusing, and the need for some width for color flow display box will markedly reduce frame rate.

5.  65. Answer: C.

Widening color box reduces frame rate by increasing the number of scan lines per box.

6.  66. Answer: C.

For the simplified Bernoulli equation to work, the lesion has to be a discrete stenosis. In serial lesions, there may be incomplete recovery of pressure and flow area may be smaller than the anatomic area before the second lesion is encountered. Hence the pressure gradient at the first orifice estimated by the simplified Bernoulli equation will be lower than the actual gradient because of the unmeasured kinetic energy between two orifices. Hence, the total gradient is not the sum of 4V2 at the two orifices. For long tubular lesions, viscous forces predominate and Poiseulle's equation would be applicable to analyze the pressure–flow relationship. Simplified Bernoulli equation does not apply to describe pressure–flow relationship when energy associated with flow acceleration is significant as in nonobstructed valve.

7.  67. Answer: B.

Describes the relationship between different types of energies as potential (pressure) kinetic (flow) and viscous forces along a flow stream. Energy can be transformed from one form to the other but cannot be destroyed or created.

8.  68. Answer: A.

Says that mass cannot be destroyed and hence flow rates at different locations in a flow stream are the same at a given point in time.

9.  69. Answer: A.

In the case of PISA, flow rate at PISA surface is same as the flow rate at the vena contracta. Flow rate is a measure of mass of blood transported per unit of time

10. 70. Answer: A.

Based on the principle that flow rate at LVOT is same as that of flow rate at AS vena contracta.

11. 71. Answer: B.

Is based on simplified Bernoulli equation.

12. 72. Answer: B.

Driving pressure influences the jet area independent of regurgitant volume as jet area is proportional to the kinetic energy (KE) imparted to the jet, which is proportional to the jet, volume, and also the driving pressure (KE = 1/2 MV2 where M = mass of blood and V = velocity). Increase in driving pressure will also increase the regurgitant volume for a given regurgitant orifice. Hence doubling the driving pressure for a given regurgitant volume will double KE and jet size.

13. 73. Answer: F.

All of these affect the jet size. Compared to the central jet, a wall-hugging jet is about 50% smaller for a given volume (due to loss of kinetic energy due to wall contact) and a non-wall-hugging eccentric jet may be larger due to the Coanda effect where the jet spreads due to the pull toward the wall. Lower gains and higher filter settings reduce jet size. At a faster heart rate, due to reduced jet sampling the jet size may be underestimated. Free jet (receiving chamber at least five times the jet size) has a larger size compared to a contained jet entering a smaller chamber.

14. 74. Answer: D.

Regurgitant volume is directly proportional to the regurgitant orifice size, driving pressure, and the time over which regurgitation occurs.

15. 75. Answer: D.

Noncompliant left atrium as well as left ventricular hypertrophy will increase the hemodynamic impact of MR. Presence of aortic regurgitation will add another source of volume load on the left ventricle. Other factors that may have an adverse impact include anemia, fever, and acuteness of onset.

16. 76. Answer: D.

All of the above. Correlates of severe MR include MR jet area of ≥8 cm2, jet to left atrial area of ≥ 0.4, vena contracta diameter of ≥7 mm, effective regurgitant orifice area of ≥0.4 cm2 or 40 mm2, and systolic flow reversal in the pulmonary veins. It has to be kept in mind that wall-hugging jets are smaller for a given regurgitant volume and the effective orifice area may not be constant during systole.

17. 77. Answer: D.

The wavelength cannot be changed by the sonographer when using a fixed-focus probe.

18. 78. Answer: C.

Left ventricular cavity obliteration. The thin dagger suggests a diminishing flow area in late systole. Although this can occur on left ventricular outflow obstruction due to SAM, the peak tends to be a little earlier at this gradient. A very late peaking signal is suggestive of cavity obliteration. This is a complete velocity profile and flow acceleration is clearly seen. In mitral valve prolapse, an incomplete signal may give a spurious late peaking signal. Signal profile depends solely on the left ventricular to left atrial pressure gradient in MR; only the signal intensity depends on the instantaneous regurgitant flow rate, which determines the number of scatterers.

19. 79. Answer: D.

Note the aortic valve opening and closing clicks. There are two opening clicks indicating dyssynchronous opening of a bileaflet mechanical aortic valve and a midpeaking systolic velocity of 4.5 m/s corresponding to a peak gradient of 80 mmHg. The gradient in the prosthetic valve depends upon valve size, valve type, and flow.

20. 80. Answer: B.

Severe aortic stenosis. This is a signal occupying the ejection phase and directed to the right shoulder, which is typical of aortic stenosis. A flail posterior mitral leaflet may cause a jet directed in this direction but is holosystolic starting with the QRS complex. The signal of aortic regurgitation is diastolic. The pulmonary stenosis signal is recorded best from the left parasternal, apical, or subcostal locations.