422exam1

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422exam1
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2011-10-24 14:13:45
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  1. 3 techniques to evaluate ventricular
    function
    • Gated equilibrium radionuclide angiography
    • first pass
    • gated tomographic MI imaging
  2. Other names for MUGA
    • gated equilibrium radionuclide angiography (ERNA)
    • radionuclide ventriculography (RVG)
  3. Tooo few frames
    • results in crap temporal resolution,
    • image flicker during image display because of large change in counts from one frame to the next.
  4. Too many frames
    • results in statistical noise
    • too few counts per image, causing poor image res
  5. Improper gating of ECG signal can result in
    • loss of counts in first several frames of
    • data
    • if acquisition begins after maximum
    • filling (end diastole)
  6. MUGA views
    • anterior
    • LAO (used for EF)
    • left lateral
  7. for accurate manual or
    automatic edge detection.
    • There must be adequate
    • contrast (count differential) between anatomic structures
  8. Contrast is a function of:
    • spatial resolution (matrix size)
    • RBC labeling integrity
    • soft tissue attenuation
    • patient positioning
    • counting statistics
  9. Quality Assurance
    Checks for ROIs
    • Are LV edges correct? Does ROI include all
    • of LV?
  10. Is left atrium excluded from LV systolic
    frames?
  11. Is bkg ROI correct? Does it exclude excessive extracardiac activity?
  12. if ROI does not include all of LV?
    EF will be lower
  13. If LA is included in ROI
    EF lower, says you havent ejected anything.
  14. LV ef formula normalized
    =bkg cts * heart pixels / bkg pixels
  15. LV ef formula
    Net ED cts - Net ES cts/ net ED cts
  16. without normalizing
    ef can be underestimated.
  17. Too big of backround subtraction (bkg over spleen or aorta)
    Overestimation of EF
  18. underestimation of ef can be caused by
    • LA in LV ROI
    • poor seperation of RV and LV
    • too little bkg subtraction w/o normalizaiton
    • variable gating.
  19. Functional
    (parametric) images
    • Show changes in counts in each pixel
    • related to a physiologic parameter
  20. Formed using matrix arithmetic
  21. Stroke volume
    • produced by subtracting ED-ES
    • The amount of blood ejected from the ventricles with each beat of the heart
  22. Paradox image
    • subtract ES-ES
    • Results in negative values in pixels in normal areas and positive values in areas of dyskinesis.
    • useful in demonstation of aneurysm
  23. aneurysm
    An aneurysm is an abnormal widening or ballooning of a portion of an artery due to weakness in the wall of the blood vessel.
  24. “Hotter”
    septal wall (than surrounding myocardium) in BOTH rest and stress images should
    alert the NMT to
    • Pt
    • hypertension hx
  25. true
    with regard to volume curves involving shorter-than- average or
    longer-than-average beats
    low counts
  26. temporal
    smoothing of MUGA frames
    • last fame may have fewer counts if there is arrhythmia
  27. Statistical noise for counts can be a problem
    with
    • increasing
    • the number of frames
  28. A cardiac first pass study can be used to
    assess all of the following
    • cardiac shunts
    • left and right ventricular function.
  29. Buffered beat acquisition involves data
    acquired in
    list mode
  30. All of the following can yield information on
    dyskinesia
    • phase image
    • stroke image
    • paradox image
  31. Which type of collimator is best for acquiring
    a cardiac first-pass study?
    LEHS
  32. Early tracer return to the lungs signify
    left to right shunt
  33. Lack of background normalization leads to what
    results in the LVEF?
    underestimation
  34. Subtracting end-diastolic frame from the
    end-systolic frame yields?
    Paradox image
  35. Image flicker as a result of large fluctuations
    in counts between frames can be cause by
    too few frames, poor temporal resolution
  36. Stroke volume image is used to check:
    regional wall motion
  37. Time to peak filling rate represents the time
    required for the ventricle to achieve:
    fastest relaxation
  38. Brain, kidney & bladder activity in the
    Tc-MAA injected patient signifies
    right to left shunt
  39. All of the following can underestimate left
    ventricular ejection fraction
    except
    • -not all left ventricle is included in end
    • systolic ROI
  40. Subtracting end-systolic frame from the
    end-diastolic frame yields
    stroke vol
  41. Qp/Qs over 1 signifies
    left to right cardiac shunt
  42. The time-activity curve of the background ROI
    in an ERNA study will normally be
    flat
  43. Image flicker in a gated cardiac cine display
    can be reduced by which image processing protocol:
    temporal smoothing
  44. The reason for the early LV peak is:
    right to left shunt
  45. Effects of misalignments in COR can be assessed by reconstructing a line source in
    transverse plane
  46. A common method for plotting COR is
    projection angle vs pixel number
  47. Large misalignments in COR will cause:
    doughnut artifact
  48. A sinusoidal plot represents COR measurements in which camera axis?
    x
  49. Subtle detector tilt can be assessed using a COR plot in which axis?
    y
  50. A “bull’s eye artifact” can be seen with all of the following, EXCEPT:
    COR misalignment
  51. small cor shift causes
    blurring
  52. large cor shift
    causes doughnut artifact
  53. variation of COR, 64*64 and 128*128
    .5 and 1 pixel
  54. What would you do if you find a bull’s eye defect when reconstructing a SPECT phantom?
    acquire new flood correction tables
  55. RANGE of the differences in pixel counts in the entire FOV is referred to as
    integral uniformity
  56. RATE OF CHANGE of the pixel count differences across FOV:
    differental uniformity
  57. What type of a source(s) is/are used for intrinsic uniformity testing?
    point and sheet sources
  58. What would you do first if you find image blurring when reconstructing a SPECT phantom?
    acquire new COR correction then case FSE
  59. What type of a source(s) is/are used for extrinsic uniformity testing?
    sheet source
  60. What would you do if you find a doughnut defect when reconstructing a SPECT phantom?
    call FSE
  61. The background ROI used to in determining % GE reflux is placed over the
    lower left lung
  62. A semi-log plot is used to calculate stomach half-emptying time of which of the following?
    liquid
  63. Slices from which tomographic plane is used to create transaxial slices in the cardiac plane?
    transverse
  64. In dual phase gastric emptying study the liquid phase is labeled with:
    In-111 dtpa
  65. The “star” artifact during image reconstruction can be minimized by:
    decreasing number of projections
  66. The background ROI to calculate GBEF is ideally placed where?
    in the liver
  67. Normal gall bladder ejection fraction range
    >35%

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