CT Review

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CT Review
2013-03-19 02:34:21
computed tomography

exam review for computed tomography
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  1. The routine transit time for barium through the GI tract is typically ____
    30-90 min
  2. Define cerebral blood volume (CBV).
    quantity of blood (mL) contained within a 100-g volume of brain tissue
  3. What are the normal ranges for Glomerual Filtration Rate (GFR)?
    • men= 70
    • women= 60
  4. Define Feldkamp-Davis-Kress (FDK) algorithm.
    cone beam correction used to correct potential x-ray scatter errors on MSCT systems
  5. What is the normal range for cerebral blood flow (CBF) in gray matter?
    50-60 mL/100g/min
  6. Define convolution
    mathematical filtration used by the CT system to remove blurring artifacts during the back-projection method of image reconstruction.
  7. Define Agatston Score
    quantification of volume and density of calcium in the coronary arteries, used to indicate a patient's risk of suffering a cardiac event.
  8. What is the CT Dose Index (CTDI)?
    approximate measure of the radiation dose received in a single CT section or slice.
  9. Define edge gradient.
    streak artifact that occurs at the interface between a high-density object (example: surgical clips) and the lower-attenuation material surrounding it (example: liver)
  10. What is the normal range for cerebral blood volume?
    4-5 mL/100g
  11. Define uticaria.
  12. Define cerebral blood flow (CBF).
    quantity of blood (mL) that moves through 100g of brain tissue each minute.
  13. Cranial nerve #8 is called the ____.
  14. Define Slice Sensitivity Profile (SSP).
    represents degree of broadening that occurs along the z-axis during volumetric data acquistion
  15. what does window width control?
  16. Define full width at half maximum (FWHM).
    midpoint of a SSP where the effective section with is determined
  17. Define contrast resolution.
    ability to detect objects with a small difference in linear attenuation.
  18. Define ray.
    portion of the x-ray beam that falls on a single detector.
  19. what does window level control?
    brightness (density)
  20. Define fomite.
    object that has been contaminated by infectious organisms or microbes
  21. Define syndesmosis.
    the articulation between the distal tibia and fibula.
  22. what is the major controlling factor of exam quality for a coronary CTA?
    patients heart rate.
  23. what are the branches of the left coronary artery?
    anterior descending and circumflex arteries.
  24. what are the types of iterative methods of reconstruction?
    • simultaneous
    • ray-by-ray
    • point-by-point
  25. define epidural hematoma
    hematoma between the skull and outer most meningeal covering of the brain
  26. what is used in CT to measure mineral content of bone?
    quantitative CT
  27. what area(s) of the brain does not enhance after IV contrast?
    posterior horn of the lateral ventricles
  28. what is the hall mark CT finding for focal nodular hyperplasia of the liver?
    central scar that remains hypo dense after initial contrast administration.
  29. define contre-coup
    brain injury on the opposite side of traumatic impact.
  30. areas of calcium identified must demonstrate relative attenuation values greater than ____.
    130 HU
  31. why should you angle the gantry 15 degrees superior to the IOML during a head CT?
    to reduce radiation dose to the orbits.
  32. what is the ideal heart rate for a CTA chest?
    65-70 bpm
  33. what is the average density of a benign solitary pulmonary nodule?
    165-200 HU
  34. what factor(s) does spatial resolution rely on?
    • focal spot size
    • detector size and spacing
    • FOV
    • pixel size 
    • detector sampling rate
  35. Colonography images are best desplayed in a ____ window setting.
    wide (lung) type
  36. the stanford type __ dissecting aneurysms affect the descending aorta.
  37. Which of these does not commonly become calcified?
    a.) thalamus
    b.) pineal gland
    c.) choroid plexus
  38. each iliac artery bifurcates into the internal and external iliac arteries at the level of ____
  39. stanford type A dissecting aneurysms affect the ____ aorta
  40. the aorta bifurcates into the left and right common iliac arteries at ____
  41. dual phase imaging with arterial and venous phase is used to evaluate ____
    mesenteric vasculature
  42. glioma is a tumor of the ____
  43. CTA of the brain should have a delay of ____ after the bolus.
    12-20 sec.
  44. define Glomerulus
    portion of the nephron responsible for filtering out unwanted substances from the blood
  45. what is the primary clinical indication for non contrast cardiac CT?
    coronary artery calcium (CAC) quantification for the assessment of atherosclerosis.
  46. define spondylolithese
    forward slipping of upper vertebra over the lower.
  47. the liver receives 75% of its blood from the ____
    portal vein.
  48. where is cerebrospinal fluid produced?
    choroid plexuses
  49. what are the primary enhancement phases of the liver?
    • arterial
    • portal venous
    • equilibrium
  50. what composes the circle of Willis?
    • anterior/posterior communicating arteries
    • anterior/posterior cerebral arteries
    • internal carotid artery
  51. what are the retro-peritoneal structures?
    • duodenum
    • pancreas
    • adrenals
    • kidneys
    • ureters
    • bladder
  52. what part of the cardiac cycle corresponds to the T-wave of an ECG?
    complete cardiac diastole.
  53. what is the difference between ionic and non ionic iodinated contrast?
    non ionic contrast has a lower osmoality than ionic.
  54. azotemia is ____ nitrogenous materials in the blood.
  55. define Mean Transit Time (MTT)
    time it takes for blood to pass through an area of brain tissue.
  56. the duodenum is suspended from the diaphragm by the ____
    ligament of Treitz
  57. the kidneys are usually located where?
  58. coronal imaging through the sinuses is typically performed with the plane of imaging ____ to the hard palate
  59. the liver recieves 25% of its blood from the ____
    hepatic artery
  60. what are the stages of infection
    • incubation
    • prodromal
    • active
    • convalescence
  61. the most common indication for CT gueded radiofrequency ablation is in treatment of neoplasms involving the ____
  62. the spinal cord tapers into the ____
    conus medullaris
  63. what imaging plane is spondylolithesis best demonstrated?
  64. what is the average HU for an un-enhanced liver?
    45-65 HU
  65. define cortical-medullary phase
    late arterial phase
  66. temporal resolution is primarily affected by:
    gantry rotation speed and number of slices per rotation.
  67. what determines the number of HU on a specific image?
    window width
  68. what is a disadvantage of a small focal spot?
    reduced heat capacity
  69. define beam hardening artifacts
    result from preferential absorption of low-energy x-rays, leaving only high intensity x-rays to strike the detector.
  70. how is image quality evaluated?
    • spatial resolution
    • low-contrast resolution
    • temporal resolution
  71. what is the primary advantage of filtering the x-ray beam?
    reduces radiation dose to the patient
  72. what is the difference in raw data and image data?
    • 1.) raw data has not been made into and image
    • 2.) raw data must be accessed to reformat images
    • 3.) image data results once the computer has processed raw data and is the visualized image