SPI Ultrasound Physics Exam Practice Questions with correct Answers

The sonographer may avoid aliasing by altering the: - Answer- image depth Which statement regarding the differences between pulsed and continuous wave Doppler is NOT correct? - Answer- CW Doppler offers significantly improved range resolution. The coupling gel used for ultrasound exams provides the same function as what transducer component? - Answer- matching layer What is the frequency of a transducer with a 10mm element, 14kHz PRF and a propagation speed of 5 millimeters / microsecond? - Answer- 2.5MHz Which of the following correctly describes the positive predictive value (PPV) of a testing technique? - Answer- If the test result is positive, PPV is the probability that the patient actually has the disease What console setting can be changed to adjust the propagation speed of the transmitted wave? - Answer- None of the above. Propagation speed is determined by the properties of the media it travels through. There is no way to adjust the propagation speed unless you scan a different media. Which of the following characteristics of an LCD monitor determines the spatial resolution of the 2D image? - Answer- number of pixels Some US systems allow you to adjust the beam thickness or slice thickness. Decreasing the slice thickness will primarily improve ___________________ resolution. - Answer- Elevational Which operator control can be used to adjust the image contrast? - Answer- dynamic range If there is no diastolic flow demonstrated on a Doppler tracing of the arcuate artery of the upper pole of the right kidney, what will the resistive index be? - Answer- 1.0 Which of the following correctly describes Real-time Virtual Sonography? - Answer- technique that enables the display of real-time ultrasound B-mode images and CT or MR images __________ resolution is the ability to resolve two closely spaced structures which lie perpendicular to the sound beam. - Answer- Lateral Which setting should be lowered to the minimum level when beginning to evaluate the patient using the orbital window? - Answer- Output power What type of probe is preferred for extremity vascular imaging? - Answer- Linear Blood flow volume changes in the body are mainly controlled by what two factors? - Answer- cardiac function and peripheral resistance Increasing the pulse repetition frequency improves: - Answer- temporal resolution The ability to differentiate a hyperechoic hemangioma within the hypoechoic liver tissue is due to what type of image resolution? - Answer- contrast resolution Which of the following describes the correct way to measure the acceleration time on a Doppler waveform? - Answer- place a caliper at the onset of the systolic upstroke and at the systolic peak The ALARA principle describes: - Answer- the rule of thumb for adjusting gain before output power to minimize ultrasound exposure Increasing the sector size, increases: - Answer- the number of pulses per image Which of the following types of resolution varies with different depths on the image? - Answer- lateral resolution Increasing the spectral Doppler sample size will increase the ___________________. - Answer- spectral broadening Glutaraldehyde is used to: - Answer- disinfect the transducer after a patient exam Which of the following is inversely related to the Doppler shift? - Answer- speed of the sound in tissue Which of the following should be increased when evaluating venous flow on Doppler? - Answer- color priority Which two factors determine the focal depth of a transducer? - Answer- element diameter and frequency Which of the following types of PE crystals are usually used for high frequency transducers (>18MHz) used in musculoskeletal exams ? - Answer- quartz Color Doppler is evaluated with what type of phantom? - Answer- Fluid Filled Phantom ______________________ resolution is defined as the ability of an ultrasound system to differentiate structures on an image based on variations in the brightness of the echo/pixel. - Answer- Contrast The matching layer for a transducer is usually made of plastic and is approximately ________________ . - Answer- 1/4 of the probe wavelength in thickness The artifact that is produced when the incident beam hits a curved surface and produces an acoustic shadow is referred to as: - Answer- defocusing The best obtainable angle of insonation for vascular evaluation that is most commonly used to provide Doppler shift information is_________degrees. - Answer- 60 Preferred levels of axial and lateral resolution will demonstrate: - Answer- low numerical values Volume averaging artifact causes: - Answer- degraded contrast and spatial resolution Which of the following is a responsibility of a Sonographer when assisting with an intravascular ultrasound? - Answer- to operate the ultrasound machine controls from outside the sterile field If beam intensity decreases from 10mW/cm2 to a level of 2.5mW/cm2, the output power was adjusted by _______. - Answer- -6dB Which of the following is true regarding a pulsed wave Doppler device? - Answer- Has the ability to detect a Doppler shift at a specific location along the path of the beam. Which of the following statements is true regarding the differences between a vector array compared to a phased sector array? - Answer- The vector array has a smaller footprint than the phased sector array. Which of the following transducers provides the best spatial resolution of the cardiac structures? - Answer- transesophageal array ______________________ is defined as the spatial peak intensity divided by the spatial average. - Answer- Beam uniformity ratio What system parameter is evaluated by scanning all three sides of the AIUM test object and compiling the images? - Answer- registration ___________ increases the strength of all of the reflected signals, regardless of reflector depth. - Answer- Overall gain Which type of bioeffects research uses data acquired from patients or subjects that have been exposed to ultrasound to describe the bioeffects that were experienced? - Answer- empirical approach _______________________ = period X # cycles in pulse - Answer- pulse duration Which of the following describes the difference between side lobes and grating lobes? - Answer- Grating lobes are seen with arrays and side lobes are seen with single element probes. The AIUM has stated that there have been no confirmed reports of thermal bioeffects to living mammals with ultrasound exposure, if the temperature rise in tissue is less than: - Answer- 2 degrees Celsius Which of the following is related to an increase in the spatial pulse length of an US beam produced by the transducer? - Answer- decrease in probe frequency Intensity = ___________________________. - Answer- Power / Beam area Which transducer would provide the lowest attenuation rate? - Answer- 2.5MHz To obtain a longer near zone: - Answer- change from a 3MHz to a 6MHz transducer. Which of the following is directly related to the peak Doppler shift detected in an artery? - Answer- transducer frequency Which statement regarding high frequency transducers is correct? - Answer- A multi-Hz transducer operates at multiple frequencies and offers a broad bandwidth. If the Sonographer increases the size of the field of view, the frame rate will ___________________. - Answer- decrease Which color Doppler control helps to find a balance between the accuracy of the color displayed and the temporal resolution of the image? - Answer- packet size What is the average Nyquist limit for a 5MHz CW Doppler probe? - Answer- None of the above. A CW probe is not limited by the PRF and Nyquist limit because the beam is not pulsed. Venous blood flow in the legs is propelled toward the heart by: - Answer- muscle contraction and respiration Transmit Delay or Receive Focusing improves _____________________ resolution. - Answer- angular and azimuthal All of the following are sound parameters processed by the pulse echo system, except: - Answer- blood flow velocity Which of the following imaging parameters is responsible for the ability to resolve the AP wall thickness of an artery? - Answer- axial resolution Which type of transducer has the smallest field of view in the near field? - Answer- sector Which of the following will improve slice thickness resolution? - Answer- adding an external focusing lens The digital memory is composed of picture elements called: - Answer- pixels What is the function used with color Doppler analysis to assess the data from multiple sampling sites and produce a display representing mean flow velocities? - Answer- Autocorrelation ____________ uses the amplitude of the Doppler shift and the intensity of the red blood cells to be able to generate color on the image independent of the angle of insonation. - Answer- Power Doppler In a vessel with a focal stenosis, the lowest pressure is found ____________________________. - Answer- at the narrowest point in the vessel Which of the following statements is true regarding decreased frame rate? - Answer- Increased line density will lead to a decreased frame rate. If the reflector dimensions are less than the wavelength of the pulse, __________________ occurs. - Answer- Rayleigh scatter If the amplitude of the ultrasound wave decreases by 1/2 with a constant beam area, what happens to the intensity of the beam? - Answer- decreases to 25% of original value. If the beam area is constant but the amplitude doubles, the intensity will increase by a factor of 4 If the beam area is constant but the amplitude decreases by 1/2, the intensity will decrease by a factor of 4 As transducer frequency increases: - Answer- axial and lateral resolution will improve Which of the following transducers would have the best axial resolution? - Answer- 2mm spatial pulse length While scanning the thyroid, you select three focal zones for the image, 1cm, 2cm and 3cm depth. Which focal zone will demonstrate the highest beam intensity? - Answer- 1cm What type of transducer has a cylindrical beam profile? - Answer- annular array Which of the following can be used to eliminate the dead zone on the image? - Answer- use a standoff pad The narrowest point of the ultrasound beam is called: - Answer- focal zone If media 1 has an impedance of 65rayls and media 2 also has an impedance of 65rayls, what percentage of the beam will be reflected at their interface? - Answer- 0% Lowering the transducer frequency will: - Answer- increase the mechanical index The ______________ is defined as the time it takes for one pulse to occur. - Answer- pulse duration What can be used to alter the displayed brightness of the image after it has been stored in the memory? - Answer- Post-Processing What is the twinkle artifact? - Answer- mosaic colors displayed in a linear pattern posterior to a dense object, such as a renal stone Diagnostic ultrasound is described as frequencies greater than: - Answer- 2MHz Increasing scan line density leads to improved __________________ resolution. - Answer- spatial Axial resolution varies directly with __________________________. - Answer- spatial pulse length Which of the following is a function of the pulser used to increase the signal to noise ratio? - Answer- coded excitation When scanning using harmonic imaging, the second harmonic frequency is 10MHz. What is the fundamental frequency? - Answer- 5MHz While scanning the carotid artery, you obtain a Doppler tracing. Before recording the image, you increase the cursor angle from the last sample taken and record the new image. How will this change affect the detected frequency shift in the new sample? - Answer- increase Overgaining on an US exam can cause ________________________. - Answer- overestimation of Doppler velocity If you change from transducer with a 40mm crystal thickness to one with a 20mm crystal thickness, the frequency of the sound produced will: - Answer- double What effect does frequency compounding have on the image? - Answer- Reduce speckle artifact Which of the following would brighten the image without affecting beam intensity? - Answer- increase the amplitude of reflected sound Pulse inversion imaging improves ________________ while degrading __________________. - Answer- spatial resolution, temporal resolution Which of the following lists all of the components of the US system? - Answer- transducer, receiver, memory, pulser, display Which of the following will increase spectral broadening on the image? - Answer- increased sample volume size All of the following transducers can be focused at multiple depths, except: - Answer- mechanical single element When the image is frozen, an ellipse can be used to measure the ______________ of a structure. - Answer- area Activation of B-color is used to improve: - Answer- contrast resolution Which of the following image controls can be adjusted to produce a smoother color Doppler image? - Answer- persistence Which of the following console controls can be used to increase the number of scan lines used in a color image? - Answer- persistence A 7MHz transducer emits a range of frequencies between 4MHz and 10MHz. What is the bandwidth of the transducer? - Answer- 6MHz You are scanning at a depth of 5cm using a 3MHz transducer and switch to a 5MHz transducer without changing the depth setting. Which transducer has the greatest pulse repetition frequency? - Answer- they have the same PRF Harmonic imaging leads to : - Answer- decreased image clutter Which of the following parameters is NOT operator adjustable? - Answer- Frequency If you change from 4MHz to 2MHz transducer frequency what happens to the detected Doppler shift? - Answer- It will decrease by 50%. Increasing the number of pulses in a color packet will: - Answer- increase frame time If the reflector is moving away from the stationary sound source, the reflected wave will: - Answer- have a lower frequency than the transmitted frequency The magnitude of the Doppler shift in color Doppler determines: - Answer- the color luminance What system component determines the initial amplitude of the ultrasound wave? - Answer- the transducer Which of the following instrument controls does the sonographer use to adjust the amplitude of a reflected of sound wave? - Answer- Receiver gain Which of the following is NOT adjustable by the Sonographer? - Answer- Demodulation