Chapter 5 - Doppler Principles

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1. A narrowing of the lumen of a tube is called a _________.

Explanation

A narrowing of the lumen of a tube is called stenosis. Stenosis refers to the abnormal narrowing of a tubular structure, such as a blood vessel or a digestive tract. This narrowing can restrict the flow of fluids or substances through the tube, leading to various symptoms depending on the location and severity of the stenosis.

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About This Quiz
Doppler Effect Quizzes & Trivia

This quiz, titled 'Chapter 5 - Doppler Principles', explores key components and functions of the circulatory system, including the heart and capillaries. It assesses understanding of fluid dynamics... see morelike viscosity and Doppler ultrasound applications in medical diagnostics, enhancing learners' grasp of human anatomy and biophysics. see less

2. The _____ are the tiniest vessles in the circulatory system?

Explanation

Capillaries are the tiniest vessels in the circulatory system. They are responsible for the exchange of oxygen, nutrients, and waste products between the blood and the surrounding tissues. Capillaries have thin walls that allow for the diffusion of substances, and their large surface area facilitates efficient exchange. Unlike veins and arteries, which have thicker walls and carry blood to and from the heart, capillaries are the site of exchange and connect the smallest arteries (arterioles) to the smallest veins (venules).

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3. Pressure is ______ per unit area.

Explanation

Pressure is defined as the force exerted per unit area. In other words, it is the amount of force applied over a given area. Therefore, the correct answer is force.

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4. If a 5 kHz doppler shift corresponds to 100 cm/s, then a 2.5 kHz shift corresponds to _______ cm/s

Explanation

The relationship between the doppler shift and the velocity is directly proportional. In this case, a 5 kHz shift corresponds to 100 cm/s. Therefore, if the shift is halved to 2.5 kHz, the corresponding velocity would also be halved to 50 cm/s.

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5. The doppler shift is the difference between  ______ and ______ frequencies

Explanation

The doppler shift is the difference between the frequencies of sound waves that are emitted and received. When an object emitting sound waves is in motion, the frequency of the waves appears higher to an observer in front of the object and lower to an observer behind the object. This shift in frequency is known as the doppler shift and is caused by the relative motion between the source of the sound waves and the observer.

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6. When incident sound direction and reflector motion are not parallel, calculation of the refelcted frequency involves the _______ of the angle btwn these directions

Explanation

When incident sound direction and reflector motion are not parallel, the calculation of the reflected frequency involves the cosine of the angle between these directions. The cosine of an angle is a trigonometric function that relates the length of the adjacent side of a right triangle to the hypotenuse. In this context, it is used to determine the change in frequency of the reflected sound wave based on the angle between the incident sound direction and the motion of the reflector.

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7. _____________ flow involves random and chaotic flow patterns, with particles flowing in all directions.

Explanation

Turbulent flow involves random and chaotic flow patterns, with particles flowing in all directions. It is characterized by irregular fluctuations in velocity and pressure, resulting in mixing and diffusion of particles. In turbulent flow, the fluid moves in eddies and swirls, causing a high level of mixing and energy dissipation. This type of flow is commonly observed in situations where there is high velocity, large pressure gradients, or irregular surfaces.

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8. If the pressure is greater at one end of the liquid-filled tube or vessle than it is at the other, the liquid will flow from the _____ pressure and to the _____ pressure end.

Explanation

When the pressure is greater at one end of the liquid-filled tube or vessel than at the other, the liquid will flow from the higher pressure end to the lower pressure end. This is because fluids always flow from areas of higher pressure to areas of lower pressure, following the path of least resistance. Therefore, the correct answer is "higher, lower".

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9. If operating frequency is doubled, the Doppler shift is

Explanation

When the operating frequency is doubled, the Doppler shift is also doubled. This is because the Doppler shift is directly proportional to the frequency of the wave. As the frequency increases, the change in frequency caused by the Doppler effect also increases. Therefore, when the operating frequency is doubled, the Doppler shift will also double.

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10. Which Doppler angle yields the greatest Doppler Shift?

Explanation

The Doppler angle of 0 degrees yields the greatest Doppler Shift. This is because at 0 degrees, the angle between the direction of the wave and the direction of motion of the source or observer is minimal, resulting in the maximum change in frequency. As the angle increases or decreases from 0 degrees, the Doppler Shift decreases.

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11. Poise is a unit of

Explanation

The correct answer is viscosity. Viscosity is a measure of a fluid's resistance to flow. It is a property of fluids that determines how easily they flow and how much they resist deformation. Poise is the unit used to measure viscosity, named after French physician Jean Louis Marie Poiseuille.

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12. Doppler shift displays are not dependent on Doppler angle.

Explanation

It is dependant on the angle

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13. If a color doppler instrument shows two colors in the same vessel, it always means flow is occuring in opposit directions in the vessels.

Explanation

The statement is false because the presence of two colors in the same vessel on a color doppler instrument does not always indicate flow occurring in opposite directions. It could be due to other factors such as turbulence or aliasing. Therefore, the presence of two colors in the same vessel does not necessarily imply flow in opposite directions.

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14. Stenosis affects _________

Explanation

Stenosis affects all of the above parameters. Stenosis refers to the narrowing or constriction of a blood vessel or a valve, which can impact the flow of blood. It can cause a decrease in peak systolic flow speed, as the narrowed opening restricts the amount of blood that can pass through during systole. Stenosis can also affect end diastolic flow speed, as the narrowed vessel or valve can impede the filling of blood during diastole. Additionally, stenosis can cause spectral broadening, which refers to the widening of the Doppler spectrum due to turbulence caused by the narrowed passage. Finally, stenosis can affect the window, which refers to the area or region being examined for the presence of stenosis.

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15. Increasing the ensemble length _______ the frame rate.

Explanation

Increasing the ensemble length decreases the frame rate. This means that as the ensemble length, which refers to the number of individual frames in a sequence, increases, the frame rate, which is the number of frames displayed per second, decreases. This is because a longer ensemble length requires more time to process and display each frame, resulting in a slower frame rate.

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16. The _______ effect is used to detect and measure ________ in vessels.

Explanation

The Doppler effect is used to detect and measure flow in vessels. The Doppler effect refers to the change in frequency or wavelength of a wave when there is relative motion between the source of the wave and the observer. In the context of blood flow in vessels, the Doppler effect is used to measure the velocity and direction of blood flow by analyzing the changes in frequency of the ultrasound waves reflected by the moving blood cells. Therefore, the correct answer is doppler, flow.

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17. The characteristic of a fluid that offers resistance to flow is called?

Explanation

Viscosity is the correct answer because it refers to the characteristic of a fluid that offers resistance to flow. It is a measure of the internal friction within a fluid, and it determines how easily the fluid can flow. A higher viscosity means a thicker, more resistant fluid, while a lower viscosity means a thinner, more easily flowing fluid.

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18. Turbulent flow is more likely proximal or distal to a stenosis

Explanation

Turbulent flow is more likely to occur distal to a stenosis. This is because as blood flows through a narrowed or stenotic vessel, it experiences increased resistance, leading to changes in flow patterns. Distal to the stenosis, the blood flow is more likely to become turbulent due to the abrupt changes in vessel diameter and increased velocity. Proximal to the stenosis, the flow is more likely to be laminar as it has not yet encountered the resistance of the stenosis.

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19. Which control can be used to help with clutter?

Explanation

The wall filter control can be used to help with clutter. The wall filter is a digital signal processing technique that removes low-frequency noise and clutter from ultrasound images. It filters out unwanted signals that may interfere with the clarity of the image, reducing clutter and improving image quality. By adjusting the wall filter control, the user can effectively manage and reduce clutter in the ultrasound image.

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20. If flow speed is doubled, the Doppler shift is

Explanation

When the flow speed is doubled, the Doppler shift also doubles. This is because the Doppler shift is directly proportional to the velocity of the source or observer relative to the medium through which the wave is traveling. Increasing the flow speed by a factor of 2 will result in a doubling of the Doppler shift.

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21. As flow resistance increases, volumetic flow rate will

Explanation

As flow resistance increases, it creates more obstacles for the fluid to flow through, resulting in a decrease in the volumetric flow rate. This is because the increased resistance causes a higher pressure drop across the system, reducing the flow velocity and ultimately decreasing the amount of fluid passing through per unit time.

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22. The angle dependencies of Doppler shift displays and Doppler power displays are different.

Explanation

Power display does not depend on an angle

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23. In color doppler instruments, color is used only to represent flow direction.

Explanation

Color Doppler instruments use color to represent both flow direction and velocity. By assigning different colors to different flow directions (such as red for flow towards the transducer and blue for flow away from the transducer), the instrument provides a visual representation of the blood flow patterns. Additionally, the intensity or brightness of the color is used to represent the velocity of the blood flow, with brighter colors indicating higher velocities. Therefore, the statement that color is used only to represent flow direction is incorrect.

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24. Steering the color window to the right or left produces a(n) _____ frame rate

Explanation

Steering the color window to the right or left does not have any direct impact on the frame rate. The frame rate refers to the number of frames displayed per second, which is determined by the hardware and software capabilities of the system. Adjusting the color window does not affect the processing power or speed of the system, so the frame rate remains unchanged.

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25. Motion of an echo-generating structure causes an echo to have a different _______ from that of the emitted pulse.

Explanation

When an echo is generated, it is caused by the motion of an echo-generating structure. This motion affects the frequency of the echo, causing it to be different from that of the emitted pulse. The frequency of a wave refers to the number of complete cycles it completes in a given time period. Therefore, the correct answer is frequency.

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26. Doubling the width of a color window produces a(n) ________ frame rate.

Explanation

When the width of a color window is doubled, it means that the number of pixels in the window is also doubled. This means that the graphics card needs to process and render twice as many pixels, which requires more computational power. As a result, the frame rate, which is the number of frames displayed per second, is halved. This is because the graphics card takes longer to render each frame, leading to a slower frame rate.

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27. If flow resistance is doubled, volumetric flow rate is

Explanation

If the flow resistance is doubled, it means that it becomes harder for the fluid to flow through the system. This increased resistance will result in a decrease in the volumetric flow rate. Therefore, the correct answer is "halved," indicating that the flow rate will be reduced by half.

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28. Doppler-power imaging indicates (with color) the  _______ of flow.

Explanation

Doppler-power imaging indicates the presence of flow.

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29. Increasing ensemble length ________ color sensitivity and accuracy and ______ frame rate

Explanation

Increasing ensemble length improves color sensitivity and accuracy, as more data from different sources can be combined to enhance the overall quality of the image. However, it decreases frame rate, as more time is required to process and combine the additional data, resulting in a slower refresh rate.

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30. Compared with Doppler-shift imaging, Doppler-power imaging is ___________ .

Explanation

Doppler-power imaging is more sensitive, angle independent, aliasing independent, and speed independent compared to Doppler-shift imaging. This means that Doppler-power imaging has the ability to detect smaller changes in blood flow, is not affected by the angle at which the ultrasound beam hits the blood vessels, does not produce aliasing artifacts, and is not influenced by the speed of blood flow.

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31. As stenosis progresses, which fo the following increase(s)?

Explanation

As stenosis progresses, both lumen diameter and spectral broadening increase. Lumen diameter decreases due to the narrowing of the blood vessel caused by the stenosis. Systolic and diastolic doppler shifts also increase due to the turbulent blood flow caused by the stenosis, leading to spectral broadening. Therefore, more than one of the above options increase as stenosis progresses.

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32. Which of the following are parts of the circulatory system?

Explanation

The circulatory system consists of the heart, arteries, arterioles, capillaries, venules, and veins. The heart pumps blood throughout the body, while arteries carry oxygenated blood away from the heart to the organs and tissues. Arterioles are smaller branches of arteries that help regulate blood flow. Capillaries are tiny blood vessels where oxygen and nutrients are exchanged with waste products. Venules collect blood from the capillaries and carry it to the veins. Veins return deoxygenated blood back to the heart.

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33. Flow resistance in a vessel depends on _______.

Explanation

The correct answer is "all of the above". Flow resistance in a vessel depends on all of the given factors - vessel length, vessel radius, and blood viscosity. Vessel length affects resistance because the longer the vessel, the more frictional resistance there is to blood flow. Vessel radius also affects resistance because a smaller radius leads to increased resistance. Blood viscosity, which refers to the thickness or stickiness of the blood, also affects resistance as thicker blood has higher resistance. Therefore, all of these factors contribute to flow resistance in a vessel.

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34. If pressure difference is doubled, volumetric flow rate is

Explanation

When the pressure difference is doubled, the volumetric flow rate also doubles. This is because according to Bernoulli's principle, an increase in pressure difference leads to an increase in fluid velocity. As a result, the fluid flows through the system at a faster rate, causing the volumetric flow rate to double.

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35. When the speed of a fluid is constant across a vessel, the flow is called _____ flow.

Explanation

In plug flow, the speed of the fluid remains constant across the vessel. This means that the fluid flows in a uniform manner without any disturbances or mixing. It is characterized by a cylindrical or plug-like flow profile, where the fluid elements move in parallel layers without any radial mixing. This type of flow is commonly observed in certain industrial processes and can be advantageous for maintaining consistent conditions within the vessel.

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36. To flow is to move in a ______.

Explanation

To flow is to move in a stream.

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37. In a stenosis, the pressure if _______ the proximal and distal values.

Explanation

In a stenosis, the pressure is less than the proximal and distal values. This is because a stenosis is a narrowing or constriction in a blood vessel, which restricts the flow of blood. As a result, the pressure upstream (proximal) to the stenosis is higher, while the pressure downstream (distal) to the stenosis is lower. Therefore, the pressure in a stenosis is less than both the proximal and distal values.

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38. Volumetric flow rate decreases with an increase in ____.

Explanation

The volumetric flow rate refers to the volume of fluid that passes through a given point in a unit of time. According to the question, the volumetric flow rate decreases with an increase in vessel length and blood viscosity. This means that as the length of the vessel increases or the viscosity of the blood increases, the flow rate of the fluid decreases. This can be explained by the fact that longer vessels and more viscous fluids create more resistance to the flow, resulting in a decrease in flow rate.

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39. In practice, approximately ________ pulses are requried to obtain one line of color doppler information.

Explanation

In practice, approximately 10 pulses are required to obtain one line of color Doppler information. This means that the ultrasound machine emits 10 pulses of sound waves and receives the echoes back from the tissues to create a single line of color Doppler image. This process is repeated multiple times to generate a complete color Doppler image.

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40. In which of the following can Doppler ultrasound detect flow?

Explanation

Doppler ultrasound can detect flow in the heart, arteries, and veins. Doppler ultrasound uses sound waves to measure the speed and direction of blood flow. It can be used to assess blood flow in the heart, such as detecting abnormal blood flow patterns or blockages in the coronary arteries. It can also be used to evaluate blood flow in the arteries and veins of the body, helping to diagnose conditions such as peripheral artery disease or deep vein thrombosis.

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41. A region of bright color on doppler shift display always indicates the highest flow speeds.

Explanation

A region of bright color on a Doppler shift display does not always indicate the highest flow speeds. The brightness of the color in a Doppler shift display represents the strength or intensity of the signal, not necessarily the velocity or speed of the flow. The velocity of the flow is typically represented by the color itself, with different colors indicating different velocities. Therefore, a bright color region could indicate a strong signal but not necessarily the highest flow speeds.

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42. Flow resistance decreases with an increase in ______.

Explanation

The correct answer is vessel radius. Flow resistance is directly proportional to vessel length and inversely proportional to vessel radius. As the vessel radius increases, the flow resistance decreases because there is more space for the blood to flow through, resulting in a lower resistance to flow. Conversely, if the vessel radius decreases, the flow resistance increases. Blood viscosity also affects flow resistance, but it is not the only factor that can cause a decrease in flow resistance.

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43. __________ flow occurs wen straight parallel streamlines describing the flow are altered.

Explanation

Disturbed flow occurs when straight parallel streamlines describing the flow are altered. This means that the flow pattern is no longer smooth and regular, but instead becomes irregular and chaotic. This can be caused by various factors such as obstacles in the flow, changes in velocity or pressure, or the presence of turbulence. In disturbed flow, the streamlines may become curved, twisted, or broken, indicating a disruption in the flow pattern.

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44. Poiseuille's equation predicts a(n) ________ in flow speed with a decrease in vessel radius.  

Explanation

According to Poiseuille's equation, there is an inverse relationship between flow speed and vessel radius. As the vessel radius decreases, the flow speed decreases. This is because a smaller radius creates more resistance to flow, resulting in a slower flow speed.

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45. If Doppler angle is doubled, the doppler shift is

Explanation

When the Doppler angle is doubled, it means that the angle between the direction of the wave and the direction of motion of the source or observer is increased. As a result, the component of the velocity along the line of sight decreases, leading to a decrease in the Doppler shift. Therefore, the correct answer is decreased.

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46. Color Doppler frame rates are _________ gray-scale rates.

Explanation

Color Doppler frame rates are typically lower than gray-scale rates. This is because color Doppler imaging requires more data to be processed and displayed compared to gray-scale imaging. The color Doppler technique involves analyzing the velocity and direction of blood flow, which requires additional calculations and rendering of color overlays on the gray-scale image. As a result, the frame rate for color Doppler imaging is often reduced to maintain image quality and accuracy.

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47. Proximal to , at, and distal to a stenosis ________, must be constant.

Explanation

The correct answer is turbulent flow. When there is a stenosis (narrowing) in a blood vessel, the flow of blood proximal to (before), at, and distal to (after) the stenosis becomes turbulent. Turbulent flow is characterized by chaotic and irregular flow patterns, with eddies and swirls. In contrast, laminar flow is smooth and orderly, while disturbed flow is a combination of both laminar and turbulent flow. Volumetric flow rate refers to the volume of fluid passing through a given area per unit of time and is not necessarily constant in the presence of a stenosis.

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48. Doppler-shift imaging indicates (with color) the  __________ of flow.

Explanation

Doppler-shift imaging indicates the presence, direction, and speed of flow. It can provide information about the movement of fluids or objects, such as blood flow in the body or the velocity of a moving vehicle. The color coding in Doppler-shift imaging helps to visually represent the different characteristics of flow, allowing for a comprehensive understanding of its properties.

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49. Higher flow speed always produces a higher doppler shift on a spectral display

Explanation

This statement is false. The Doppler shift is determined by the relative motion between the source of the wave and the observer. The speed of the flow does not directly determine the amount of Doppler shift. Other factors, such as the angle of incidence and the frequency of the wave, also play a role in determining the Doppler shift. Therefore, it is not always true that higher flow speed produces a higher Doppler shift on a spectral display.

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50. About  ________ frames per seocnd are produced by a color Doppler instrument.

Explanation

The correct answer is "More than one of the above." The question is asking about the number of frames per second produced by a color Doppler instrument. Since the options provided are 10, 20, 40, 80, and "More than one of the above," it suggests that the instrument can produce a frame rate that is greater than 80 frames per second. Therefore, the correct answer is "More than one of the above."

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51. Steering the color window to the right or left changes ________. (multiple answers)

Explanation

Steering the color window to the right or left changes the Doppler angle and Doppler shift. The Doppler angle refers to the angle at which the ultrasound beam intersects the blood flow, and changing the steering of the color window can alter this angle. The Doppler shift refers to the change in frequency of the ultrasound waves as they interact with moving blood cells, and adjusting the color window can affect the detection and measurement of this shift.

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52. If the incident frequency is 1 MHz, the propagation speed is 1600 m/s, and the reflector speed is 16 m/s toward the source, the Doppler shift is _________________ MHz.

Explanation

2 x 16 x1 / 1600 =
32/1600 = .02

2 x velocity x frequency / c

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53. Flow increases if _____ increase(s).

Explanation

Flow increases if both pressure difference and pressure gradient increase. When there is a greater pressure difference between two points, there is a higher driving force pushing the fluid through a system, resulting in increased flow. Similarly, a steeper pressure gradient indicates a greater change in pressure over a given distance, leading to increased flow. Therefore, both A (pressure difference) and B (pressure gradient) are correct explanations for the increase in flow.

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54. Flow resistance depends most strongly on ____.

Explanation

The flow resistance in a vessel is determined by various factors, but the most significant one is the vessel radius. As the radius of the vessel decreases, the flow resistance increases exponentially. This is because a smaller radius leads to a smaller cross-sectional area, resulting in a higher velocity of blood flow and increased frictional forces between the blood and the vessel walls. Therefore, vessel radius has the strongest influence on flow resistance.

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55. Which of the following is increased if Doppler Angle is increase?

Explanation

If the Doppler angle is increased, it will result in an increase in the effect of angle error. The Doppler angle refers to the angle between the direction of the ultrasound beam and the direction of blood flow. When this angle is increased, it can lead to errors in the measurement of blood flow velocity. These errors can affect the accuracy of Doppler ultrasound measurements, particularly in determining the direction and speed of blood flow. Therefore, an increase in the Doppler angle will increase the effect of angle error.

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56. Doppler signal power is proportional to ____________.

Explanation

The Doppler signal power is proportional to the cell concentration. This means that the more cells there are in a given volume, the stronger the Doppler signal will be. The Doppler signal power is not affected by the volume flow rate, flow speed, or Doppler angle. Therefore, the correct answer is cell concentration.

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57. If 2-MHz ultrasound is reflected from a soft tissue boundary moving at 10 m/s toward the source, the Doppler shift is ________ MHz.

Explanation

2 x velcoity (10) x f(2) / c (1540) = .026

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58. Which of the following on a color doppler display is (are) presented in real time?

Explanation

The gray-scale anatomy and flow direction on a color Doppler display are presented in real time. This means that the images and information displayed are continuously updated and reflect the current conditions and movements within the body. The Doppler spectrum, on the other hand, is not presented in real time as it is a graphical representation of the velocity of blood flow over time. Therefore, the correct answer is A & B.

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59. If the incident frequency is 1 MHz, the propagation speed is 1600 m/s, and the reflector speed is 16 m/s toward the source, the reflected frequency is _____________ MHz.

Explanation

1 MHz + .02 doppler shift

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60. Lack of color in a vessel containing blood flow may be attributable to ______.

Explanation

The lack of color in a vessel containing blood flow may be attributable to low color gain, a high wall filter setting, or a low priority setting. Low color gain refers to a decrease in the intensity of color signals, resulting in a lack of color representation. A high wall filter setting can filter out low-frequency signals, including color signals, leading to a lack of color. A low priority setting may prioritize other imaging parameters over color representation, causing a lack of color in the vessel.

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61. For an operating frequency of  6 MHz, a flow speed of 50 cm/s, and a Doppler angle of 60 degrees, calculate the Doppler Shift.

Explanation

Doppler Shift = 2 x V x Operating Frequency x cosine / c
2(50)6(.50) / 1.540 = 194.8 = 1.95 kHz

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62. Which of the following reduce the frame rate of a color doppler image?

Explanation

A wider color window reduces the frame rate of a color doppler image because it increases the amount of data that needs to be processed and displayed, which takes longer to complete. Similarly, an increased ensemble length also reduces the frame rate because it requires more time to collect and analyze the data from multiple pulses. These factors contribute to a slower frame rate, which may result in a less smooth and slower image display.

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63. For an operating frequency of 2 MHz, a flow speed of 10 cm/s, and a Doppler angle of 0 degrees, calcuate the Doppler Shift.

Explanation

Doppler Shift = 2 x V x Operating Frequency x cosine / c

2(2)(10) / 1.540 = 25.9 = .26KHz

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A narrowing of the lumen of a tube is called a _________.
The _____ are the tiniest vessles in the circulatory system?
Pressure is ______ per unit area.
If a 5 kHz doppler shift corresponds to 100 cm/s, then a 2.5 kHz shift...
The doppler shift is the difference between  ______ and ______...
When incident sound direction and reflector motion are not parallel,...
_____________ flow involves random and chaotic flow patterns, with...
If the pressure is greater at one end of the liquid-filled tube or...
If operating frequency is doubled, the Doppler shift is
Which Doppler angle yields the greatest Doppler Shift?
Poise is a unit of
Doppler shift displays are not dependent on Doppler angle.
If a color doppler instrument shows two colors in the same vessel, it...
Stenosis affects _________
Increasing the ensemble length _______ the frame rate.
The _______ effect is used to detect and measure ________ in vessels.
The characteristic of a fluid that offers resistance to flow is...
Turbulent flow is more likely proximal or distal to a stenosis
Which control can be used to help with clutter?
If flow speed is doubled, the Doppler shift is
As flow resistance increases, volumetic flow rate will
The angle dependencies of Doppler shift displays and Doppler power...
In color doppler instruments, color is used only to represent flow...
Steering the color window to the right or left produces a(n) _____...
Motion of an echo-generating structure causes an echo to have a...
Doubling the width of a color window produces a(n) ________ frame...
If flow resistance is doubled, volumetric flow rate is
Doppler-power imaging indicates (with color) the  _______ of...
Increasing ensemble length ________ color sensitivity and accuracy and...
Compared with Doppler-shift imaging, Doppler-power imaging is...
As stenosis progresses, which fo the following increase(s)?
Which of the following are parts of the circulatory system?
Flow resistance in a vessel depends on _______.
If pressure difference is doubled, volumetric flow rate is
When the speed of a fluid is constant across a vessel, the flow is...
To flow is to move in a ______.
In a stenosis, the pressure if _______ the proximal and distal values.
Volumetric flow rate decreases with an increase in ____.
In practice, approximately ________ pulses are requried to obtain one...
In which of the following can Doppler ultrasound detect flow?
A region of bright color on doppler shift display always indicates the...
Flow resistance decreases with an increase in ______.
__________ flow occurs wen straight parallel streamlines describing...
Poiseuille's equation predicts a(n) ________ in flow speed with a...
If Doppler angle is doubled, the doppler shift is
Color Doppler frame rates are _________ gray-scale rates.
Proximal to , at, and distal to a stenosis ________, must be constant.
Doppler-shift imaging indicates (with color) the  __________ of...
Higher flow speed always produces a higher doppler shift on a spectral...
About  ________ frames per seocnd are produced by a color Doppler...
Steering the color window to the right or left changes ________....
If the incident frequency is 1 MHz, the propagation speed is 1600...
Flow increases if _____ increase(s).
Flow resistance depends most strongly on ____.
Which of the following is increased if Doppler Angle is increase?
Doppler signal power is proportional to ____________.
If 2-MHz ultrasound is reflected from a soft tissue boundary moving at...
Which of the following on a color doppler display is (are) presented...
If the incident frequency is 1 MHz, the propagation speed is 1600...
Lack of color in a vessel containing blood flow may be attributable to...
For an operating frequency of  6 MHz, a flow speed of 50 cm/s,...
Which of the following reduce the frame rate of a color doppler image?
For an operating frequency of 2 MHz, a flow speed of 10 cm/s, and a...
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