Contrast and Spatial Resolution Practice Test

These questions are part of the practice quiz. Start practicing

• As a last resort, which human immobilizer is used to hold a patient in position?
• How is a line-pair/contrast-detail phantom used in QA?
• A radiographic grid with a k-factor of 1 would offer no change in image contrast.
• Which statement about detector pixel size and spatial resolution is true?
• Which factors contribute to motion blur in CT imaging and how can it be minimized?
• What is the effect of excessive kVp on DR image appearance?
• State the Nyquist frequency for a detector with pixel pitch p.
• In CT, what is voxel size and why does it matter for spatial resolution?
• Using antiscatter grids generally requires higher exposure to maintain film density, affecting patient dose.
• What distinguishes high-contrast resolution from low-contrast resolution?
• In mammography, what primarily determines spatial resolution and contrast?
• High image contrast is most closely related to which type of x-ray interaction?
• Which statement best describes modulation transfer function (MTF)?
• Edge enhancement can improve perceived sharpness but may create what kind of problems if overdone?
• Why might increasing exposure to improve resolution be inappropriate in clinical practice?
• Which factor most directly increases the number of grayscale shades available in a digital image?
• With suboptimal OID, the resulting radiographic image tends to show what?
• In digital imaging systems, increasing the sampling frequency of the data has what effect on image fidelity?
• Which term denotes the contrast arising from the subject's inherent tissue properties?
• How is CNR calculated, and what does it indicate?
• Which statement best describes the grayscale range of a high-contrast radiographic image?
• The Nyquist frequency is achieved by sampling at least how many times per cycle?
• What is the primary imaging outcome when applying an open-mouth odontoid LUT to a KUB?
• What two components determine final image contrast in digital radiography?
• If a digital imaging system resolves 8 lp/mm, what does this indicate?
• When switching from a 400 RS film screen combination to a 200 RS system, one should expect
• Varying tissue thicknesses and densities is referred to as
• What does a contrast-detail phantom assess in radiographic image quality?
• With digital imaging systems, the primary factors affecting final image contrast are the
• What are the benefits and drawbacks of edge enhancement in image processing?
• Which factor contributes to total image contrast and is related to the subject?
• Why is detector calibration and uniformity important for perceived spatial resolution?
• Which characteristic most contributes to high subject contrast in an imaging scenario such as the ankle joint?
• Which type of radiograph provides the most clinical information?
• What is the difference between display resolution and sensor resolution?
• Explain windowing (level/width) and its impact on perceived contrast and resolution.
• Which statement best defines MTF?
• For general radiography, an MTF value of 1 is
• When choosing between two radiographic grids, the grid with the higher K factor results in
• Which radiograph below exhibits the best recorded detail?
• Define the Modulation Transfer Function (MTF) and explain its significance for image quality.
• Immediately after exposure and prior to post-processing, the initial image typically shows which level of contrast?
• What units are typically used to report spatial resolution in radiography and CT?
• Spatial resolution is improved when
• Which factors influence the detectability index d' in imaging?
• Which statement about MTF is correct?
• What is the effect of using smaller voxels on spatial resolution and dose?
• What filtration thickness is used in the highest image quality parameter set listed?
• In a pinhole camera method for measuring PSF and MTF, what does the Fourier transform of the PSF yield?
• A radiographic grid with a K-factor of 1 would offer what effect on image contrast?
• Which statement correctly describes the typical shape of anatomical structures in radiography?
• Which term describes a broad density range on an image?
• Detective Quantum Efficiency (DQE) is a measure of what aspect of an imaging detector, and what is its effect on image quality?
• What is a convenient and easy patient immobilization method an experienced radiographer will use?
• The ankle joint exhibits high subject contrast due to differences between which tissue types?
• Increasing kVp reduces the difference between minimum and maximum photon energies.
• In digital radiography, what does EI stand for?
• What is the effect of using sharper reconstruction kernels on spatial resolution and noise in CT?
• What best describes the general shape of most human anatomical structures in radiography?
• The sampling rate described as 2x per cycle is known as what concept in imaging?
• Factors affecting recorded detail include
• Which effect does increasing the source-to-image distance (SID) have on imaging geometry?
• Selecting an open-mouth odontoid LUT and applying it to a KUB will yield a final image with which characteristic?
• How can detector lag affect temporal/spatial resolution?
• In the pediatric chest radiograph scenario, the competent radiographer would do which technique change to improve image quality?
• Define dynamic range in imaging systems.
• Low mAs in radiography typically results in which type of image degradation?
• How does display bit-depth affect perceived contrast resolution?
• The visualization of a scar on a wrist projection due to digital detectors is primarily due to which detector characteristic?
• What is MTF50 and why is it useful?
• Which method uses a near-point source projected onto a detector to estimate the system's PSF?
• How does increasing OID influence image sharpness?
• Differentiate geometric unsharpness from motion blur.
• A radiograph that demonstrates considerable differences between gray shades is said to have
• All of the following affect visibility of detail EXCEPT
• In digital imaging, which statement best describes a determinant of spatial resolution?
• Which detector characteristic best explains why a soft tissue mass may be visible on a wrist radiograph with a scar?
• Which condition can lead to artifacts in edge-preservation deconvolution?
• Explain Partial Volume Effect (PVE) and its consequence in CT imaging.
• What does FSS stand for and why is it important?
• The following term best matches the concept of a gradient that describes speed of density change on the H&D curve.
• Which formula correctly expresses geometric unsharpness in radiography, and which factors influence it?
• A frontal chest radiograph showing faint spinal outlines and many gray shades indicates which combination?
• Low mAs in radiography primarily results in which type of degradation?
• Which statement best describes the role of CNR in lesion detectability?
• What effect does quantum mottle have on image quality when exposure is low?
• The composite measure of image accuracy compared to the original object, on a scale of 0 to 1 is referred to as?
• Which statement about Modulation Transfer Function (MTF) is true?
• Which processing step in digital radiography adjusts brightness and contrast after image acquisition?
• As object spatial frequencies increase, how does MTF change?
• In CT image reconstruction, what is a key reason to prefer smoother kernels over sharper kernels in some cases?
• Which term denotes a radiographic image characterized by high contrast?
• What should you expect to occur with a decrease in kVp, using digital receptors?
• What does modulation transfer function quantify in imaging?
• How does decreasing pixel pitch p affect the Nyquist frequency?
• Which statement correctly identifies the MTF in imaging systems?
• In fluoroscopic imaging with barium, the resulting image typically has which scale of contrast?
• What is the difference between sampling frequency and true spatial resolution?
• With digital imaging technologies, the final brightness and contrast appearance of an image is due to
• The principal controlling factor of radiographic contrast when using film-screen technology?
• All of the following factors would affect radiographic subject contrast EXCEPT
• What is the impact of using a larger focal spot on spatial resolution?
• Which statement about penumbra is true?
• Applying a high-contrast look-up table (LUT) to a chest radiograph would produce which grayscale result?
• Spatial resolution in digital imaging is determined by
• To improve temporal resolution on an image, what should be used?
• Image receptor contrast of radiographic film is expressed as the ____ of the D log E curve.
• In mammography, which factors influence image contrast?
• Which practice helps improve both contrast and spatial resolution in radiographic studies?
• Nyquist sampling states that the maximum resolvable frequency is 1/(2p). What is the effect of reducing pixel size?
• Switching from a 10:1 grid to a 6:1 grid commonly results in which effect on image visibility?
• Which of the following describes a final image with high contrast visualization of lumbar spine anatomy after LUT application?
• As kVp increases, the percentage of Compton interactions __________ and image contrast __________.
• A frontal projection chest radiograph that demonstrates a faint outline of the thoracic spine and many shades of gray to show the pulmonary markings of the lungs illustrates
• What is a potential consequence of high sampling frequency when the optical resolution is poor?
• A radiograph that demonstrates minimal differences between gray shades is said to have
• What does pixel bit depth primarily determine in a digital image?
• Which statement best describes the difference between contrast resolution and spatial resolution?
• In general radiography, quantum noise is a function of which factors?
• With increasing kVp levels, using digital receptors and DR technologies, which statements are true?
• Line pairs per millimeter (lp/mm) measure the number of line pairs that can be distinguished per millimeter. What does a higher lp/mm value indicate?
• Which description best aligns with long-scale contrast?
• Which option is NOT a contributing factor to total image contrast?
• The descriptor used to express the rate of density change on the H&D curve is which?
• Quantum noise impacts radiographic image quality by doing what?
• What is the trade-off of the air-gap technique in radiography?
• What does lp/mm measure in imaging system specifications?
• Which feature of the D log E curve expresses image receptor contrast?
• Which of the following best lists practical steps to optimize both contrast and spatial resolution?
• The total amount of irradiated material is a function of which factors?
• Grids are used to reduce scatter in radiography. What is a typical consequence when a grid is used?
• In imaging system specifications, what does lp/mm stand for?
• If the sampling frequency is less than the Nyquist value, which artifact can occur?
• To reduce patient entrance skin exposure (ESE), higher kVp exposures are considered. Which statement is true?
• Poor spatial resolution is caused by unacceptable levels of
• When digital imaging receptors are used, an exposure at 90 kVp would require a grid.
• How does scatter degrade image contrast, and what methods mitigate it?
• Which approach balances spatial resolution and image noise when selecting processing parameters?
• Which factors determine the total amount of irradiated material?
• How does increasing exposure (mAs) influence spatial resolution?
• Edge-preservation deconvolution effect on resolution and artifacts?
• Which statement best describes the line spread function (LSF) and its relation to spatial resolution?
• If the system PSF becomes narrower, what happens to spatial resolution?
• Spatial resolution is the ability to distinguish two closely spaced objects. Which two metrics are commonly used to quantify spatial resolution?
• Quantum mottle is photon noise; which imaging factor primarily causes it?
• A digital detector with a high fill factor will produce what?
• Which exposure parameter set would yield the highest image quality given the listed options?
• Raising the kilovolt peak (kVp) has what effect on the range of photon energies produced?
• Which statement best describes how MTF relates to spatial frequency in imaging?
• Which factor does not primarily contribute to spatial resolution in digital imaging?
• The slope of the H&D curve is described by which descriptor?
• Partial Volume Effect becomes more pronounced for which condition?
• Which condition improves recorded detail?
• Which statement best defines spatial resolution in radiography?
• Which term describes an image with many shades of gray, indicating a broad density range?
• What is the MTF roll-off and what causes it?
• In digital imaging using a DR detector, image contrast decreases with
• An increase in x-ray beam filtration would
• Penumbra decreases as
• A radiograph with few shades of gray exhibits what type of contrast?
• Which statement about Contrast-Noise-Ratio (CNR) is false?
• Kilovoltage peak (kVp) controls the proportional relationship of which pair of interactions?
• Which factor does not directly affect geometric unsharpness according to the standard formula U = FSS × (OID / SOD)?
• For optimal visibility of detail in a digital radiographic image, which factors are most important?
• How does a uniform detector response influence perceived image sharpness?
• Imaging noise is different from quantum noise in that imaging noise
• Radiographic image contrast is the combination of which two components?
• Lowering kVp tends to have which effect on image contrast?
• As kVp increases with digital DR imaging, the histogram becomes
• Partial volume averaging occurs when voxels contain multiple tissues; what is the typical effect on lesion conspicuity in CT?
• Which term is used to describe an image with many shades of gray due to a broad density range?
• The ____ represents a depth to the information in the digital image
• A fluoroscopic examination using barium as a contrast material would typically produce images with what scale of contrast?
• The difference between two adjacent gray shades on a radiographic image is known as what?
• Switching from 400 RS to 200 RS typically results in
• Which of the following does not increase image contrast?
• Increasing OID generally results in
• Nyquist sampling states that the maximum resolvable frequency is 1/(2p), where p is the pixel size. What is the practical effect of using smaller pixels?
• Which factor is explicitly identified as a contributing factor to total image contrast?
• What is FWHM and how is it used in evaluating the PSF?
• Dynamic range in digital imaging refers to
• What is the effect of increasing the focal spot size on geometric blur?
• Which detector design factor most directly contributes to higher spatial resolution?
• What does SNR tell us about an image?
• Increased beam filtration results in which of the following?
• Why does detector pixel size limit digital image spatial resolution?
• What does Modulation Transfer Function quantify in an imaging system?
• The traditional unit of resolution measurement typically used in film/screen imaging is
• What is a consequence of using antiscatter grids in radiography?
• Increasing the spatial frequency of object details generally has what effect on MTF?