Download CT Board Review - Medical CT Registry Exam Review: Questions and Answers and more Exams Nursing in PDF only on Docsity!
CT Board Review - Medical CT Registry Exam Review A patient has a severe vagal reaction to iodinated contrast material that includes bradycardia. Initial treatment may include Correct Answers Atropine After the injection of intravenous contrast material during a CT examination of the brain, which anatomic area does not enhance? Correct Answers Posterior horn of the lateral ventricle An image that is reconstructed a second time with some change in technical factor is termed _____. Correct Answers Retrospective Areas of a CT image that contain minimal changes in tissue density are electronically represented by Correct Answers Low spatial frequencies Before a CT image can be reconstructed by a computer, the transmission signal produced by the detectors must be converted into numeric information by a(n) Correct Answers Analog-to- digital converter During CT angiography, images may be reconstructed using only the greastest density encountered along each ray. This type of specialized CT image is called a(n) Correct Answers MIP image How often should an average CT number water calibration test be performed? Correct Answers Daily
Statistical noise appears as ___ on a CT image Correct Answers Graininess The abdominal aorta bifurcates at the level of Correct Answers L The ability of a CT scanner to image a small high-density object is controlled by ___ of the scanner Correct Answers Spatial resolution The average CT value for blood is approximately Correct Answers +45 HU The contast resolution of a CT scanner is not related to which of the following? A.) Focal spot size B.) Section width C.) Reconstruction algorithm D.) Signal-to-noise ratio Correct Answers A.) Focal spot size The dimensions of a voxel may be calculated as the product of which of the following? A.) Matrix size and pixel size B.) Pixel size and section width C.) DFOV and matrix size D.) DFOV and pixel size Correct Answers B.) Pixel size and section width The intensity of the CT xray beam can be increased by Correct Answers Decreasing collimation
C.) Spurious signals from moving signal wires D.) Cost Correct Answers B.) Translation motion What anatomical structure forms a roof over the posterior cranial fossa and is shaped like a tent? Correct Answers Tentorium cerebelli What are the primary advantages of narrower section thicknesses? Correct Answers Improved spatial resolution and reduced partial volume averaging What change will occur in the number of detected photons if a section thickness is changed from 5 mm to 10mm? Correct Answers Increase 100% What determines the section thickness? Correct Answers Incident beam collimation What does the matrix size describe? Correct Answers Number of pixels used to display an image What effect would an array processor failure have on image processing? Correct Answers Increase image display time. What filter selection would provide the best detail for imaging of the internal auditory canals? A.) Smooth B.) Sharp C.) Standard D.) Soft Correct Answers B.) Sharp
What geometric factors will have an effect on spatial resolution? Correct Answers Focal spot size, detector aperture width What has an effect on image quality? Correct Answers Spatial resolution, Contrast resolution, Noise What helical or spiral computed tomography term is defined as the table increment in distance per mm per 360 degrees gantry rotation divided by the section thickness in mm? Correct Answers Pitch What Increases signal to noise ration? Correct Answers Increased mA, wider section thickness, increased detection efficiency What interaction between xray and matter results in the largest amount of occupational exposure? Correct Answers Compton effect What is an advantage of scans of the pituitary taken in the coronal plane? A.) IV contrast material is better visualized. B.) Streak artifacts are reduced or eliminated. C.) The patient is more comfortable during scanning. D.) The patient receives a lower radiation dose. Correct Answers B.) Streak artifacts are reduced or eliminated. What is not commonly used as a CT scintillation detector material? Correct Answers Silver halide
because dense bone has too severely attenuated the xray beam? Correct Answers Photon starvation What term is used to describe as the ability to display an image of a large object that is only slightly different in density from its surroundings? Correct Answers Contrast resolution What term is used to describe the computed tomography appearance of an intracerebral hemorrhage as a result of a higher CT number of the hemorrhage as compared to normal brain tissue? Correct Answers Hyperdense What type of drug is Demerol? Correct Answers Analgesic What type of scan geometry is responsible for producing ring artifacts? Correct Answers rotate-rotate What will help to reduce partial volume artifacts? Correct Answers Scanning thinner sections When compared with conventional radiography, CT produces diagnostic images with improved Correct Answers Low- contrast resolution Where is contrast media introduced for a myelography exam of the spinal canal? Correct Answers Subarachnoid space Which describes the relationship between section thickness and noise? A.) If section thickness increases, noise increases B.) If section thickness increases, noise decreases
C.) If section thickness decreases, noise decreases D.) If section thickness decreases, noise remains unchanged Correct Answers B.) If section thickness increases, noise decreases Which fo the following is the central value in a range of gray shades used to display the image? A.) Window width B.) Window level C.) Region of interest D.) Dose index Correct Answers B.) Window level Which of following results from a fracture in the temporal region of the skull with associated tearing of the middle meningeal artery? A.) Subdural hematoma B.) Epidural hematoma C.) Arteriovenous malformation D.) Subarchnoid hematoma Correct Answers D.) Epidural hematoma Which of the following accurately describes the relationship between patient dose and pitch? A.) If pitch increases, patient dose increases B.) If pitch increases, patient dose decreases C.) If pitch decreases, patient dose decreases D.) If pitch decreases, patient dose remains unchanged Correct Answers B.) If pitch increases, patient dose decreases Which of the following algorithm types provides the greatest soft-tissue detail during a CT study of the pelvis?
Which of the following conditions may be visualized in a CT study of the brain? A.) Glioblastoma B.) Wilm's Tumor C.) Krukenberg Tumor D.) Plasmacytosis Correct Answers A.) Glioblastoma Which of the following CT numbers would appear as a gray shades when a window width of 300 and a window level of 0 are selected? A.) Ct numbers above + B.) Ct numbers between +150 and + C.) Ct numbers between +150 and - D.) Ct numbers below -150 Correct Answers C.) Ct numbers between +150 and - Which of the following describes rapid, irregular, ineffective twitches of the ventricles? A.) Ventricular regurgitation B.) Ventricular palpitations C.) Ventricular arrythmia D.) Ventricular fibrillation Correct Answers D.) Ventricular fibrillation Which of the following determines the maximum number of shades of gray that can be displayed on the CT monitors? A.) Window level B.) Window width C.) Pixel size D.) Matrix size Correct Answers B.) Window width
Which of the following increases the signal-to-noise ratio of a CT image? A.) Decreased aperature size B.) Decreased mAs C.)Increased filtration D.) Increased aperature size Correct Answers D.) Increased aperature size Which of the following is a solid-state device used to record the light flashes given off by a scintillation crystal? A.) Photomultiplier tube B.) Anode C.) Photodiode D.) Input phosphor Correct Answers C.) Photodiode Which of the following is a streak artifact oriented tangentially to a flat surface having a high spatial frequency? A.) Low contrast artifact B.) Edge gradient artifact C.) Equipment induced artifact D.) Signal artifact Correct Answers C.) Edge gradient artifact Which of the following is affected by the slice spacing in a CT study? A.) Spatial Resolution B.) Quantum Mottle C.) Radiation Dose to the Patient D.) Signal-to-Noise Ration Correct Answers C.) Radiation Dose to the Patient Which of the following is convolution?
C.) 30%
D.) 50% Correct Answers A.) 1-3% Which of the following is the term used to describe a voxel value that is the average of multiple tissue types contained within the voxel? A.) Linear attenuation coefficient. B.) Partial volume averaging. C.) Low contrast resolution. D.) Edge gradient averaging. Correct Answers Partial volume averaging. Which of the following provides optimal liver lesion detection following the introduction of contrast media? A.) Scanning prior to the equilibrium phase B.) Scanning during to the equilibrium phase C.) Scanning after to the equilibrium phase Correct Answers A.) Scanning prior to the equilibrium phase Which of the following reconstruction methods is used by most modern CT scanners? A.) Back-projection B.) Iterative methods C.) Fourier tranform D.) Filtered back-projection Correct Answers D.) Filtered back-projection Which of the following section widths would cause the greatest amount of partial volume averaging? A.) 1mm B.) 3mm
C.) 5mm D.) 10mm Correct Answers D.) 10mm Which of the following should be viewed with relatively wide window widths? A.) Lung and inner ear B.) Lung and brain C.) Inner ear and brain Correct Answers A.) Lung and inner ear Which of the following technical changes may increase the partial volume effect present on a spiral CT scan? A.) Decrease the pitch B.) Decrease the aperature size C.) Increase in matrix size D.) Increase in pitch Correct Answers D.) Increase in pitch Which of the following terms are commonly used to describe the ability of a CT scanner to differentiate objects with similar linear attenuation coefficients? A.) Spatial resolution B.) Contrast resolution C.) Spatial resolution and sensitivity D.) Sensitivity and contrast resolution Correct Answers D.) Sensitivity and contrast resolution Which of the following terms defines the increase in the mean energy of a polychromatic beam as it passes through an object? A.) Partial volume effect B.) Beam hardening C.) Cross-field uniformity Correct Answers B.) Beam hardening
