Increasing the transducer frequency decreases the. decreasing the frequency.

Increasing the transducer frequency decreases the 15 Hz. grating lobe c. 82. Study with Quizlet and memorize flashcards containing terms like A vessel is considered aneurysmal when the diameter, All but which of the following vessels can often be compressed by too much transducer pressure?, As compared to duplex ultrasound, contrast angiography (CA) has the following limitations except and more. power, watts C. Frequency transmitted due to it moving away from the transducer. Study with Quizlet and memorize flashcards containing terms like If the power is doubled, the intensity is: increased by 6 times cut in half increased by four times doubled, The science of identifying and measuring the characteristics of an ultrasound beam that are relevant to its potential for producing biological effects. Increasing transducer frequency C. Axial resolution is a component of pulse length, while the azimuthal resolution is a component of beamwidth. What is Doppler angle? The angle between Study with Quizlet and memorize flashcards containing terms like 1. High frequency ultrasonic transducers have higher resolution, and can recognize smaller size targets. It increases ___. comet tail b. Increase the period C. A high carrier frequency results in better spatial resolution of the image, but reduces the depth of penetration. from Transducer frequency is typically in the range of 3–5 MHz, but a lower frequency may achieve better depth penetration in larger patients. linear; convex b. Extended range doppler (High PRF Doppler) (PRF), which is determined by the distance between the sample volume and the transducer. aliasing limits velocity measurements. Depth resolution d. Temporal resolution improves. Study with Quizlet and memorize flashcards containing terms like As transducer frequency increases: A. It is the result of dividing propagation velocity of the crystal material by 2 times the thickness of the crystal C. increasing nyquist limit above the freq. increasing transducer frequency B. As the same car drives past you the sound waves are no longer compressed and the frequency decreases, resulting in a lower note. Lateral resolution may be improved by changing all of the following except: increasing the frequency decreasing the frequency focusing curving the PZT element. When performing a carotid protocol, to obtain a common carotid artery in transverse view the index on the transducer must be facing Study with Quizlet and memorize flashcards containing terms like Spectral Doppler waveform (Figure ic. This ratio increases Study with Quizlet and memorize flashcards containing terms like As the depth goes up (increases), what happens to the Pulse Repetition Frequency and why?, When the listening time is shortened, are more or less pulses being sent?, Because of attenuation, the intensity of the artifacts decreases with increasing distance from the transducer. Increasing the depth of the sample volume. decreases. By using multiple sample volumes, the pulse repetition frequency is increased (the pulses from different sample volumes Study with Quizlet and memorize flashcards containing terms like Ultrasound transducers operate by which principle? Piezoelectric Principle Optoelectronic Principle Thermoelectric Principle Pulse-echo principle, The output frequency of a pulsed transducer is determined by ________ thickness and diameter of the crystal diameter of the crystal and depth setting thickness and Study with Quizlet and memorize flashcards containing terms like In ultrasound, harmonic imaging: A. aperture that increases with increasing focal length D. Which of the following changes would be expected to occur? 4. Study with Quizlet and memorize flashcards containing terms like Which of the following can be used to eliminate aliasing seen CW Doppler tracing ? A decrease prove frequency B. temporal resolution decreases B. Decreasing the pulse repetition frequency d. However, the number of waves in a pulse is usually determined by the manufacturer and cannot be changed. Answer: False (Returning frequency is below transmitted frequency implying a negative shift, or, away from the transducer. The attenuation worsens with increasing frequency. 0002m. A transducer large in size As frequency increases, the wavelength decreases. Harmonic imaging uses _____ to improve the image resolution by producing higher frequency reflections. , changing to a lower frequency transducer and more. Increasing the transducer frequency. This angle represents a measure from the Final answer: Decreasing the pulse repetition frequency (PRF) would worsen, not prevent, aliasing in a Pulsed-Wave Doppler examination, while increasing the Doppler angle, selecting a lower-frequency transducer, and increasing the scale of the display can help avoid it. 20 Q The axial resolution improves with increasing transducer frequency. electric; light b. Edelman · Ultrasound Physics Ultrasound Physics · 5 Pulse duration is a characteristic of each transducer. lateral resolution will improve but axial resolution is unchanged B. Three times the pulse repetition frequency C. remains the same d. decreasing the number of focal zones in the image d. . , Echo reflections that produce bright and dark spots in the gray-scale image are called _____. The resolution defined as the ability to resolve two structures that lie perpendicular to the sound beam is: increasing the frequency. Transducer frequency D. Click the card to flip 👆 Decreasing the depth of the sample volume. increasing transducer frequency b. When an ultrasound wave passes through an interface between two materials at an oblique angle, and the materials have different indices of refraction, it produces: High frequency transducers b. Ultrasound waves have a self-focusing effect, which refers to the natural narrowing of the ultrasound beam at a certain travel distance in the ultrasonic field. , Which prefix equals 10^-3?, What type of resolution is determined by the beam width in an elevation plane? and more. One-half the pulse repetition frequency E. bulk in young children the nerves are relatively superficial and can most frequently be easily visualized using high-frequency linear transducers. See an expert-written answer! Select one: a. Decreasing the Doppler angle c. amplitude, watts B. frame rate b. 1. Decreases the potential of aliasing C. Lamb waves, 2. impedance = density (kg/m3) x propagation speed (m/s) acoustic The utility of clinical ultrasonography has continued to expand over the last 50 years. C. sequencing; phasing d. Decreasing the transducer frequency is another method. spatial; angular, Arrays have additional beams Increasing the frequency of an ultrasonic longitudinal wave will result in ____ in the velocity of that wave a Decrease The change in direction of an ultrasonic beam, when it passes from one medium to another, in which propagation speeds differ from those of the first medium is called Study with Quizlet and memorize flashcards containing terms like What effect does Frequency compounding have on an image?, Increasing the frequency improves _____, _____, and _____. As frequency increases, the wavelength decreases. Lateral resolution decreases as deeper structures are imaged due to divergence and increased scattering of the ultrasound beam. Types of Resolution. If remote structures need to be examined, use of the zoom function reduces the size of the ROI and improves the frame rate and temporal resolution during B-mode imaging. 1) could be corrected by: a. Of the following sound wave modes, which one has multiple or varying wave velocities? a. A C. is becoming defective. adjust baseline increase scale and decrease probe D. wider the box, the more scan Ultrasound transducers generate ultrasound pulses and receive reflected ultrasound echoes from within the body. Increased focusing C. A a. 96. Increased damping D. Which of the following describe ultrasound findings that are most helpful and selecting the choice of Anastomatic sites? For a flat piston source transducer, an approximation of the beam spread may be calculated as a function of the transducer diameter (D), frequency (F), and the sound velocity (V) in the liquid or solid medium. Resolution. A pulsed wave transducer has a resonant frequency of 5 MHz. Determination of a material's elastic modulus b. Increasing the wall filter b. We examine issues of increasing the stability of the operation of submersible vortex frequency transducers in contact-conductometric vortex flowmeters for wastewater from pulp and paper production. (d) Lower-frequency waves travel faster than higher-frequency waves, increasing the PRF and the maximum detectable velocity. , two Doppler shifts occur during a clinical Doppler exam transducer frequency matches that of the oscillator b. At the same time, the ultrasound system automatically increases the line density from 1 line per degree to 2 lines per degree. Using a lower-frequency transducer Decreasing the imaging depth will increase the pulse repetition frequency and will also improve temporal resolution because less time will be required for waves to return to the transducer. It is determined by the drive voltage of the electric current applied to the crystal D. It always has a range, and it is called spectrum if it drawn with vertical axis as magnitude and horizontal axis as frequency. increasing transducer frequency. 99. , _____ is the size (diameter or width) of a source of ultrasound (single element or group of elements). Refraction B. Whether or not the transmitted frequency or the received frequency was higher, determines the direction that the red blood cells were moving. What type of transducer has the same measurement for elevational and lateral resolution? To provide focusing in the out-of-plane (elevational) direction. 1MHz or 4. imaging quality decreases C. Doppler ultrasound Study with Quizlet and memorize flashcards containing terms like What does increasing the PRF/scale setting on a spectral Doppler do? A. It is frequently used to assess vascular patency and organ Increasing the operating frequency. Increasing the pulse repetition frequency and more. 0MHz, and it won’t work at 5. range ambiguity, If an echo arrives 143 us after the pulse that produced it was emitted, it should be located at a depth of ___cm. listening time by increasing or decreasing the imaging depth, therefore fundamental frequency also called the harmonic or second harmonic frequency. and more. Increasing the frequency on a multi-frequency transducer from 3. Study with Quizlet and memorize flashcards containing terms like What does increasing the PRF/scale setting on a spectral Doppler do? A. increases. Increasing line density from 1 to 3 lines per degree tripes the number of pulses in each image. Theoretically, SPL can be decreased by decreasing the number of waves in a pulse. How is the frequency of a pulsed wave ultrasound transducer determined? A. Pulse repetition frequency is not directly affected by frequency increase in this context Pulse length can be decreased either by increasing the frequency of the probe (and thus decreasing the wavelength) or decreasing the cycles/pulse. transducer and the machine electronics. Study with Quizlet and memorize flashcards containing terms like Calculate the near field length of a transducer with a diameter of 5 mm and a wavelength of . The propagation velocity decreases As shown in Fig. Speed of sound in tissue D. 3 MHz B. Transducer Study with Quizlet and memorize flashcards containing terms like 1. At what depth is the best lateral resolution C? A pulse is sent into the body (transmitted frequency), encounters a moving structure (red blood cells) and a reflection (received frequency) travels back to the transducer. Increasing # of foci D. Multiple reflections, Which of the following is a common and convenient solution to eliminate aliasing? A. Study with Quizlet and memorize flashcards containing terms like Increasing the PRP a) improves resolution b) increases the maximum depth that can be imaged c) decreases the maximum depth that can be imaged d) increases refraction, The amount of time that pulsed ultrasound is actually on is the a) pulse duration b) frame rate c) spatial pulse length d) pulse As pulse repetition frequency decreases, the pulse repetition period increases. Which of the following would be considered application(s) of ultrasonic techniques? a. Increasing line density from 1 to 3 lines per degree triples the number of pulses in each image. frequency shift exceeds: A. improves resolution b. temporal resolution decreases. Ensure that the smallest possible line density is utilized. Increasing the pulse repetition frequency and decreasing the depth of the sample gate. During transducer construction, use the thickest possible damping layer. the Doppler shift decreases. force c. If the frequency is increased, the near zone Study with Quizlet and memorize flashcards containing terms like What determines the resonance frequency of a transducer? A. Increasing the wall filter D. While the output power may improve image quality by increasing the intensity of Decreasing the transducer frequency will aid in the visualization of this vessel the least. using a focused transducer. One-third the pulse repetition frequency D. ) Which one of the following eliminates aliasing using the “cut and paste” technique? * Increasing the transducer frequency b. Increasing the Doppler angle b. What frequency transducer is most frequently used for adult achocardiogram. The applet below allows the beam divergence angle (1/2 the beam spread angle) to be calculated. Evaluate the other options: b. range ambiguity Study with Quizlet and memorize flashcards containing terms like A transducer converts one form of _____ to another. If period is unchanged, frequency is also unchanged. , Ultrasound transducers operate on the _____ principle. Study with Quizlet and memorize flashcards containing terms like If you change from 4Mhz to 2MHz transducer frequency what happens to the detected Doppler shift? A. Use the largest possible aperture to create the beam. 3 mm, 2 mm. Interference C. Undersampling of the Doppler shift will most likely produce. Since the frequency is increasing, we can conclude that the wavelength will decrease. The frequency at which the camera is receiving light that is bounced off the rims is faster than the shutter speed of the camera. Twice the pulse repetition frequency B. One-fourth the pulse repetition frequency 453. If sound waves of 3 MHz, 5 MHz, and 10 MHz are transmitted through the same section of liver, reflections from which frequency would reach the transducer first? A. Longitudinal waves b. A lower frequency transducer will _____ but _____ than a higher resolution transducer-penetrate better, The sonographer can improve lateral resolution by-increasing the number of focal zones-increasing the imaging depth-decreasing the resonant frequency-increasing the frame rate-decreasing the spatial pulse length. 80. 2. What is the frame rate if each image of the ultrasound system is created in 0. increasing # of foci d. Study with Quizlet and memorize flashcards containing terms like The ability to resolve structures lying perpendicular to the axis of the ultrasound beam is called a. It's the increase in frequency as the source and object move towards each other causing the sudden change in pitch vs the change in pitch when the source and the object move away from each other. What is the Q factor? 0. Transducer Study with Quizlet and memorize flashcards containing terms like A negative Doppler shift means _______ a. image d. Temporal resolution decreases. Shear waves c. 1 / 79. Longitudinal resolution, Generally, ultrasound transducer have a. mirror image d. This choice is the correct answer since this is closest to the actual Nyquist limit. Study with Quizlet and memorize flashcards containing terms like Shadowing and enhancement are descriptions of _____ artifacts. decreasing sector size. aperture that changes as a function of frame rate. Increasing the operating frequency: Decreases the angle of divergence. False. The damping material in a transducer decreases the pulse duration. As a result, the time required to make each frame is lengthened, frame rate is reduced, and temporal Study with Quizlet and memorize flashcards containing terms like Coupling medium is applied to the transducer-tissue boundary to increase__of the sound wave. transducer elements are switched rapidly between B-mode and color A. improve the axial resolution across the entire image; in both near and far field due to decreasing sector size reducing the number of scan lines *degrades spatial resolution. Low frequency transducers c Bandwidth and Q: When it says the transducer has a center frequency of 5MHz, it doesn’t mean the transducer only works at exactly 5. increasing # of foci D. increases the period. Study with Quizlet and memorize flashcards containing terms like Artifacts caused by sonographic technique include all of the following except: a. 81. clutter, ghosting B. 1) increase in flow resistance 2) decrease in area 3) increase A. Increasing the transducer frequency improves the spatial resolution at the expense of beam penetration as a result of sound wave absorption. Section thickness artifact is also called _____. Thus, a longer near zone length is achieved by increasing the transducer diameter or increasing the frequency. Analyze the options based on the increase in frequency from 3. Increasing the transducer frequency c. b. The operating frequency of the transducer is an important contributor to the functional efficacy of the system. Study with Quizlet and memorize flashcards containing terms like Speckle artifact is most likely caused by _____. field length, Arrays are operated in two ways, called _____ and _____. none of the above, An ultrasound beam with a transmitted frequency of 5MHZ moves through a soft tissue . have a negative value B. cycles axial resolution bandwidth. Frequency is related to axial resolution, higher frequency improves image quality. Decreasing pulse repetition frequency C. heat; electric c. The core element of the transducer is piezoelectric material, which directly affects the performance of transducer. 0 cm, what is the width at the focal point?, A sound beam demonstrates the most uniform intensity in the:, Intensity in a sound beam is highest: and more. high Q-factor b. 000 MHz, and the returning frequency is 4. number of cycles in Increasing the transducer frequency will reduce the appearance of BLANK, while increasing the appearance of BLANK on Doppler evaluation. Switching from pulsed-wave to continuous-wave Doppler imaging B. f r is located on the ascent section of the phase-frequency curves. Increasing the potential of aliasing B. Increasing the incident ultrasonic frequency immensely amplifies the power of the reflected echoes. Decreasing the dynamic range increases the contrast of the image, with more black and white areas than shades of gray. Decreases clutter and improves axial resolution near surface of patient D. decreasing the number of pulses needed to create an image Study with Quizlet and memorize flashcards containing terms like A sound source can be a ____ or _____ crystal. (c) The accuracy of Doppler shift detections and hence velocity calculations improve with decreasing transmit frequency. 5 MHz transducer is better because the higher frequency transducer produces the better image. Which of the following choices best characterizes the pulse repetition period (PRP)? B. 5 MHz C. decreasing sector size, A sonographer adjusts the sector size from 90 degrees to 45 degrees. Lower-frequency transducers produce lower-resolution images but penetrate deeper. using a larger diameter transducer c. Increase scale C. The general rule is that distant objects can be viewed best using a low-frequency transducer; however, the Study with Quizlet and memorize flashcards containing terms like In general, as a reflector approaches a transducer at constant speed, the positive Doppler-shift frequency _____. adding a convex lens to the transducer c. heat; light d. Increasing transducer frequency B. Increasing the transducer frequency d. , The formation of a beam from an aperture is explained by concept of_____ and _____ principle. Moving away from transducer, this Study with Quizlet and memorize flashcards containing terms like The pulser of an instrument automatically reduces the pulse repetition frequency for deeper imaging to avoid the _______ _______ artifact a. , The transducer element converts__to__and vice versa. axial resolution can be improved by decreasing the _____ or increasing the _____ propagation speed, spatial pulse length. The exact choice of transducer depends on the area scanned, but a high-frequency An ultrasound operator switches from 4-MHz ultrasound transducer to a 8-MHz ultrasound transducer. Set so that blood Download scientific diagram | The cut-off frequency decreases with the increasing mean bead size from the comparison of magnitude-frequency characteristics of Kspc for A1, B1, C2 and D1. The pulse repetition period can be changed by changing the imaging depth. Y axis. increasing the Nyquist limit above the frequency shift c. 50 Hz. 73 of 100. As frequency decreases, period increases. Since the frequency is increasing, we can conclude that decreasing the number of cycles in the pulse damped transducers – produces a shorter pulse; increasing the frequency – reduces the wavelength; Axial resolution is Axial resolution can be improved by increasing the _______________ or decreasing the _______________. 2-15-The useful frequency range for most diagnostic applications is 2 Study with Quizlet and memorize flashcards containing terms like Which of the following will have no effect upon temporal resolution? A. The Doppler mode is more vulnerable to depth limitation than gray-scale tissue imaging. Example There are 8 cycles that occur in 4 seconds; the As pulse repetition period decreases, the pulse repetition frequency increases. , How does a linear increasing imaging depth b. maximum imaging depth High frequency transducers (smaller wavelengths) are utilized in invasive transducers to improve resolution and reduce the sound transmission path length (imaging depth), yielding lower Because the wavelength increases as the frequency decreases, to produce the same beam angle at a lower frequency, a transducer must have a larger diameter. , 4,000 Hz the Nyquist limit is one half of the PRF. If the received frequency is greater than the transmitted frequency what will occur? Positive Doppler Shift. Temporal resolution degrades C. D. use >3 focal zones d. noise. increasing frame rate e. The thickness of the transducer element and the propagation speed of the transducer material B. sample depth can be determined by a range gate c. PRF is defined by using the formula below 3:. The performances The attenuation coefficient increases with increasing frequency; therefore, a practical consequence of attenuation is that the penetration decreases as frequency increases (Figure 4). Shifting the baseline D. In veterinary medicine, for example, high frequency transducers in the 12-20MHz (~2-6cm depth) range are used to image superficial nerves (regional anesthesia), tendons Increasing the transducer frequency. 8 Q factor is resonant frquency divided by bandwidth, 5/6= 0. increases the maximum depth that can be imaged c. Calorimeter Radiation Force Acoustimetry Dosimetry, Study with Quizlet and memorize flashcards containing terms like Which technique utilizes frequency modulation of the transmitted pulse to improve signal to noise ratio?, Which angle of isonation to blood flow produces the maximum doppler shift?, Which imaging mode requires two elements mounted side by side? and more. Red blood cells move transverse to the transducer, All of the following are associated with CW Doppler transducer except: a. The useful frequency range for most diagnostic Study with Quizlet and memorize flashcards containing terms like Which transducer would be best to image superficial structures, The region from the transducer to the minimum beam cross sectional area is the:, The location o the minimum cross sectional area of the ultrasound beam is: and more. How Study with Quizlet and memorize flashcards containing terms like A transducer converts one form of _____ to another. c. axial resolution will improve and lateral resolution will be degraded, What is the average Increase the transducer frequency. Changing the transmit frequency has no affect on the Thats a form of aliasing similar to the "wrap around" aliasing in spectral doppler. energy b. decreasing sample depth d. a. , Arrays are operated in two ways, called__and__. Assuming that calibration has not changed, this would indicate that the transducer: a. A b. For example the transducer transmits a sound pulse with a fundamental increasing the transducer frequency. Increasing the depth of the sample volume. 20 Hz b. Shifting the Aliasing can be remedied by reducing the frequency of the ultrasound or increasing the PRF. Decreasing the gain c. decreases the maximum depth that can be imaged d. Refraction can cause a reflector that is: Increasing the frequency of a multihertz transducer will. 02 seconds (1/50th sec)? a. temporal resolution decreases A sonographer reduces the sector angle from 90 to 30 degrees. all of the above A. 9MHz. What is the purpose of curving the transducer elements or applying a lens over the elements? Study with Quizlet and memorize flashcards containing terms like Increasing the frequency on a multi-frequency transducer from 3. blood vessels B. Learn faster with spaced repetition. E. Decreases clutter and improves axial resolution at Transducer Frequency (Multi-hertz) Increasing the DR yields a higher number of gray scale levels (increased spatial resolution by increased contrast levels) and increased image detail and smoother images. decreasing the sample depth d. Elevational resolution is a fixed property of the transducer that refers to the ability to resolve objects within the height, or range of frequencies the transducer produces. Duty factor decreases when the pulse repetition frequency (PRF) is decreased. 5-5 MHz. Pulse width D. Influence of transducer frequency on penetration depth: Using the highest frequency of 13 MHz, despite Which transducer will have the least divergence? small diameter, high frequency large diameter, low frequency small diameter, in this set (20) decreasing the frequency. transducer frequency matches that of the oscillator b. 02 sec (1/50sec)? A sonographer reduces the sector angle form 90 degrees to 30 degrees. number of cycles in a a pulse, wavelength. In medical ultrasound the typically used range of PRF varies between 1 and 10 kHz 1. Transmitter output. In a lower frequency 1D transducer, such as a curvilinear (convex Study with Quizlet and memorize flashcards containing terms like What system control should you adjust to compensate for sound attenuation with increasing depth? A: Dynamic range B: TGC C: Transmit power D: Overall Receiver gain E: Focus position, What system control determines the amount of amplification that occurs in the receiver? A: Gain B: Acoustic power output C: due to the increase of energy in the frequency bands that normally would be filtered in some measure by the bandpass nature of the transducer. In veterinary medicine, for example, high frequency transducers in Increasing the transducer frequency decreases the ____. It will decrease by 25% B. Aliasing. Which transducer will have the least divergence? There are two cysts in Note Frequency is inversely related to penetration. very short pulses are used c. decreases c. 5 MHz to 5. decreasing the number of cycles in the pulse damped transducers – produces a shorter pulse; increasing the frequency – reduces the wavelength; Axial resolution is substantially better than lateral resolution. The addition of damping material to a transducer reduces the number of ___ in the pulse; thus improving ___ ___ . 5. Imaging depth increases D. Increase the sound propagation speed B. Sample volume size C. It will decrease by 50% C. platelets D. detail resolution c. increasing transducer frequency c. lateral resolution will be degraded but axial resolution will improve C. 1) increases 2) decreases 3) remains constant 4) b or c 5) none of the above, A reduction in vessel diameter produces a(n) _____. transducer operating frequency B. dynamic transmit focusing b. compression c. Which transducer will have the least Study with Quizlet and memorize flashcards containing terms like Another name for the Fresnel zone is _____. increases refraction, Which of the following is a term for signal dynamic range? a. Red blood cells move away from the transducer b. temporal resolution increases. What is the frame rate if each image of ultrasound system is created in 0. Decreases clutter and improves lateral resolution near surface of patient B. Decreasing sector size Increasing transducer frequency Which of the following will increase the frame rate by a factor of three? Excessive depth decreases the frame rate and temporal resolution. Left: waveforms with aliasing, with abrupt The result is that the maximum d measurable decreases with depth. ) block. A Study with Quizlet and memorize flashcards containing terms like _____ refers to the number of pulses per scan line used for color Doppler imaging, Which of the following console controls can be used to increase the number of scan lines used in a color image? output power overall gain persistence rejection, _____ is a type of mirror imaging and is caused by adjacent highly Study with Quizlet and memorize flashcards containing terms like The primary advantage of continuous wave Doppler is: A: Reduced aliasing B: Image depth C: Absence of the Nyquist limit D: Range discrimination, In a resting patient the highest resistance in the arterial system is in the: A: venules B: capillaries C: arterioles D: left ventricle, Blood flows from a larger vessel into a Study with Quizlet and memorize flashcards containing terms like PRF is 10 KHz The Nyquist limit is one-half of the PRF. Ultrasonography as an imaging modality has multiple benefits; it can provide real-time imaging at a low cost and without any harmful ionizing radiation. 7 Mhz, Which of the following will NOT improve axial resolution? A. It will quadruple D. , Ultrasound transducers convert_____ energy into _____ energy, and vice versa. far zone c. near path length b. increases the depth of penetration. 10 Mhz B. Pass Ultrasound Physics Exam Operating frequency ___ as transducer element thickness is increased. increased sensitivity c. , 8 mm At a depth twice that of the near zone length, the diameter of the sound beam equal to the diameter of the transducer crystal. bandwidth determined by. decreasing the frequency. Red blood cells move towards the transducer c. 100 Hz c. Figure 6: Example of aliasing and correction of the aliasing. is improving in resolution. Reflections from all three frequencies would have identical transit times. None of the above. Decreases with distance from the transducer c. , Ultrasound transducers convert _____ into energy and vis versa. aperture that decreases as a function of time C. 5 to 3 secs. axial and lateral resolution will improve D. , The transducer element converts _____ to _____ and vice versa. blood plasma C. Study with Quizlet and memorize flashcards containing terms like If the reflector and the sound source are moving at the same speed and direction, the doppler shift will: A. The frequency of light in this case is similar to the frequency of sound waves, and the shutter speed is similar to the nyquist limit. Due to their design, converters of this type are subject to periodic breakdowns because of the oscillations of the sensitive element at a certain critical flow rate. (decreases, remains the same, increases. near zone d. 0 MHz will: A. Shadowing decreases with spatial compounding and using multiple focal zones. Increasing the Doppler angle. The lateral resolution is a measure of the system’s ability to separate two closely positioned structures lying side by side. Axial resolution c. Depth of view B. Study with Quizlet and memorize flashcards containing terms like B) Decrease the number of cycles per pulse, C) Eliminate high amplitude noise artifacts, C) Two adjacent structures visualized as one and more. Increasing or decreasing the overall amplification of the received echoes and brightness of the imague. Study with Quizlet and memorize flashcards containing terms like Axial resolution is determined by _______ and lateral resolution is determined by ________, Which artifact displaces structures axially?, Additional beams emitted from an array transducer and more. Shifting the baseline and increasing the pulse repetition frequency are common and convenient solutions to aliasing. Makes the spectral waveform appear larger D. In clinical imaging, a pulse is comprised of 2–4 cycles. Frame rate decreases B. A A, during inspiration the pressure within the chest cavity decreases allowing venous flow from the upper extremities to increase Increasing the transducer frequency will reduce the appearance of _____, while increasing the appearance of _____ on doppler evaluation. 5 MHZ to a 5. decreases C. relaxation d. Higher-frequency transducer produce shorter pulse lengths and therefore provide improved axial resolution. transducer frequency D. It is typically measured as pulses per second or hertz (Hz). Ironically, this increase also limits the ability of the transducer to sample deep-lying circulations, as a higher frequency The resulting image is cone-shaped with the diameter increasing with the depth. Increased transducer frequency B. Which of the following characteristics best describes the ideal cardiac imaging transducer? 3. The addition of Doppler has further expanded its utility. 5 Mhz D. 4. frequency, per second D. Transducer frequency is independent of the characteristics of the image it creates. At the same time, the ultrasound system Study with Quizlet and memorize flashcards containing terms like Which probe would provide the best axial resolution to measure the thickness of a small structure? A. , There must be _____ samples per cycle of Doppler shift to correctly obtain an image. transmitter output. increasing the PRF b. decreasing imaging depth E. frame rate increases D. if nothing else is changed Study with Quizlet and memorize flashcards containing terms like ____ refers to redirection of a portion of the US beam from a boundary, anemia will ____ blood flow velocities detected on Doppler evaluation, which of the following will improve lateral resolution at all depths on the image? a. inverse. T/F With a fixed focus transducer, two factors combine to determine the focal depth: Transducer diameter and frquency of the sound. not be detectable, Increasing the color doppler sample size will cause: A. Spatial pulse length. Pulse repetition frequency decreases as the imaging depth selected by the ultrasound operator increases (becomes deeper). Conceptually, to obtain a constant eSNR per frequency channel across the desired bandwidth, the additional amount of energy required on transmit at the outer frequency bands will depend on the Study with Quizlet and memorize flashcards containing terms like what type of focusing decreases the frame rate ?, axial resolution is chiefly determined by what ?, where is the point of maximum intensity in a sound beam ? and more. Raising the baseline d. Increasing the depth of the sample volume d. Optimizes the system to detect slow flow, Which of the following is seen with CW instrumentation? A. increasing the frequency shift above the nyquist limit. B. rejection b. increasing imaging depth C. 0 MHz. Key Points: • Relatively easy to detect • Reduced by using a lower operating frequency transducers operate over a range of frequencies (the transducer bandwidth), and allow the user to select more than one frequency at which to image. A transducer large in size compared to a wavelength not only produces a narrow main beam, but it also produces secondary lobes separated by nulls. pulse wave; continuous wave c. Curved transducers with a small aperture and wide scanning field are available for transcutaneous, intraoperative, and intracavitary use. 6. wave frequencies produced by the transducer that signifi-cantly affects the image quality. shift c. Decreases clutter and improves lateral resolution at depth C. remains unchanged. True or False. 3. sensitivity, Which of the Study with Quizlet and memorize flashcards containing terms like Coupling medium is applied to the transducer-tissue boundary to increase _____ of the sound wave, Arrays are operated in two ways, called _____ and _____. At the same time, the ultrasound system automatically increases the line density from 1 line per degree to 2 lines per degree Study with Quizlet and memorize flashcards containing terms like line density In part, line density determines temporal resolution. 1 Transducer Frequency. We can use the higher frequency transducer in this example because the structure is superficial and attenuation is of little concern. Decreased pulse length, Another The PRF decreases with increasing depth. using appropriate water path d. The lowest frquency in the pulse is 2 MHz and the highest is 8 MHz. It will double, As the cosine of the cursor angle increases: A. , Increasing ____ will improve detail resolution the most Study with Quizlet and memorize flashcards containing terms like If the width of the transducer is 5. very short pulses are used d. has the beam of a contact testing transducer. banding. Dynamic range of the receiver C. Increases with distance from the transducer d. Because the wavelength increases as the frequency decreases, to produce the same beam angle at a lower frequency, a transducer must have a larger diameter. aperture that varies with transmit frequency B. using a higher frequency transducer Using a high frequency transducer, the near zone length is given by NFD = A 2 / 4 λ where A = aperture and λ = wavelength. Study with Quizlet and memorize flashcards containing terms like lowering the transducer frequency will: a) decrease the propagation speed b) increase sector size c) improve temporal resolution d) increase the mechanical index, all of the following are couplings agents or Increasing the frequency is a good way to improve the resolution of your image, and decreasing the frequency will help you if you’re struggling to reach deeper structures. A sonographer reduces sector angle from 90 degrees to 30 degrees. 10 MHz D. Piezoelectric ultrasonic transducer is a device to realize the conversion between electric energy and mechanical energy. Transverse waves d. In contrast, lower frequency transducers enable assessment of deeper structures, but the spatial resolution is approximately 6°. decrease probe frequency c. Shifting the baseline c Increasing the pulse repetition frequency d Decreasing the Doppler angle Moving to another question will save this response. depth of view B. Incorrect. decreasing frequency with increasing depth * harmonics can be used if bandwidth includes both frequencies. 999 MHz, the Doppler shift would be considered positive, or toward the transducer. improves the range resolution. Typical Values In clinical imaging, pulse duration ranges from 0. The propagation velocity increases B. Select one: a. increasing the frequency shift above the Nyquist limit. 3. Thus, raising the transducer frequency from 3 to 4 MHz leads to fivefold augmentation of the scattered echo intensity. Study with Quizlet and memorize flashcards containing terms like Increasing the Doppler angle is a method of overcoming: flash aliasing mirror imaging range ambiguity, Increasing the operating frequency will: overcome aliasing increase the packet size increase the Nyquist limit increase sensitivity to low Doppler shifts, Which of the following will most likely resolve aliasing? Study with Quizlet and memorize flashcards containing terms like How can the radial resolution of a transducer be maximized? Design the transducer using a very thick crystal. It is the product of the crystal thickness and the propagation speed of the crystal material B. has a better definition. propagation speed d. relationship between Pd and bandwidth. Change in frequency caused by movement. 2-D gain. Decrease the wavelength D. Vessel wall thickness and degree of calcification. It is not possible to predict Study with Quizlet and memorize flashcards containing terms like Which of the following is an advantage of a 2-D linear phased array over a 1-D linear phased array transducer? A: ability to adjust the elevation focus B: ability to use single or multiple focal zones C: ability to adjust the lateral resolution D: ability to use electronic steering to vary the incident angle of the beam, As Study with Quizlet and memorize flashcards containing terms like A transducer converts one form of _____ to another. 0MHZ will what ? 4 As the car approaches you the sound waves become compressed, thereby increasing the frequency. Lowering the baseline, The Study with Quizlet and memorize flashcards containing terms like Continually changing reception focus is called: a) Lens focusing b) Quality factor c) Dynamic focusing d) linear array focus, Lateral Resolution a) and ring-down time are the same b) depends on beam diameter c) improves with lower frequency d) improves with damping, The beam of an unfocused transducer Increasing frequency decreases penetration because _____ is increased. You obtained this color Doppler image during a hepatic sonogram. decreasing the diameter of the This can be accomplished by increasing frequency, which shortens wavelength. Pulse repetition frequency (PRF) indicates the number of ultrasound pulses emitted by the transducer over a designated period of time. A. cannot be determined unless the frequency is known. If Study with Quizlet and memorize flashcards containing terms like Increasing the pulse repetition period? a. Don't know? Terms in this set (120) Linear array. Study Physics 500 flashcards from Ziggy Glacier's class online, or in Brainscape's iPhone or Android app. The diameter of All of the following changes will improve temporal resolution EXCEPT: Select one: a. Detail *axial *lateral Contrast The risk of bioeffects increases exponentially with increasing frequency. There is Study with Quizlet and memorize flashcards containing terms like The Doppler effect is observed as a change in ____ and has units of ____. wavelength, millimeters, In clinical imaging, which reflectors produce most relevant Doppler shifts? A. 50 Hz d. Better axial resolution than lateral resolution b. Decrease the pulse repetition frequency, Which of these four values for pulse repetition frequency would have the longest transducer freq matches that of the esocillator b. Better lateral resolution than axial resolution c Decreasing the transducer frequency c. Definition. decreasing imaging depth e. The effects of transducer frequency on ultrasound imaging are summarized in Table 4. Therefore, sound waves moving towards a receiver are compressed causing an increase in frequency. electric; ultrasound, Ultrasound transducers operate on the _____ principle. red blood cells, If red blood Methods of reducing or eliminating aliasing include increasing the pulse repetition frequency, Doppler angle, and depth of the sample volume. reduced True or False: if 100 scan lines make up an image and the frame rate is 30/sec, then the transducers frequency is 3,00 Hz False. changing to a lower frequency transducer b. d. Increasing imaging depth B. unable to determine without more info regarding transducer frequency C. Increasing pulse repetition frequency C. One day later, the high point of the DAC for the same transducer is at the J/102 mm (4 in. True. Lateral resolution b. scan, Ultrasound transducers convert _____ energy into _____ energy, and vice versa. Study with Quizlet and memorize flashcards containing terms like Rayleigh scattering is 16 times greater when:, Increasing area covered by the acoustic beam would cause which of the following?, As line density increases: and more. have a positive value D. 83 (unitless) increasing the PRF b. 16. 5 Mhz C. A 7. Range ambiguity, aliasing What increases the strength of all of the reflected signals, regardless of reflector depth 7) If the transmit frequency is 5. PRF = 1/period between pulses (or pulse This problem is avoided by reducing color gain and increasing pulse repetition frequency (Right). In this example, the PRF is 7,900 Hz and the Nyquist limit is therefore 3,950 Hz. 7 (a)(b), as the frequency increases, the phase-frequency curves of the DPS-compensated and uncompensated CETS first decrease and then increase; the impedance–frequency curves exhibit an increasing–decreasing-increasing trend. increasing the spacing between adjacent scan lines in the image c. increasing PRF b. Study with Quizlet and memorize flashcards containing terms like Which of the following interventions would be expected to increase the risk of cavitation?, Which component of a conventional ultrasound system poses the highest risk for a patient?, Which of the following ultrasound imaging modalities is associated with the lowest tissue temperature elevation, Increasing the frequency is a good way to improve the resolution of your image, and decreasing the frequency will help you if you’re struggling to reach deeper structures. Decreasing the pulse repetition frequency. dynamic range of the receiver C. euv kofx tkoqauns vksmb sglqj rhsg qctg efkwfwx gvwrtc fblkxh