Angio A Flashcards

1
Q

what is DSA

A
  • diagnostic imaging method that uses a computer to convert the attenuated x-ray beam into digital information, which can be manipulated and /or stored
  • involve removing or subtracting background structures from an image so that only contrast media filled structures remain
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2
Q

what is zero image

A
  • images taken before contrast administered
  • shows only bony structure
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3
Q

what is mask image

A

image reversal to create positive mask image

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4
Q

what is series image

A
  • dynamic images that were exposed while contrast was being administered through an artery during “angio cine”
  • power injector administers contrast through catheter in patient’s right femoral artery to vessel of interest
  • images are taken in rapid sequence
  • these images will be processed later for subtraction
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5
Q

difference between single plane and bi-plane system

A

single plane
- usually larger II size = larger FOV
- save space

bi-plane
- naming of plane: A-B, AP-Lat
- usually smaller footprint “II size”

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6
Q

advantages of bi-plane system

A
  • save contrast
  • save time
  • true 3D relationship
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7
Q

what is pulsed fluoroscopy

A
  • used as a method of reducing radiation dose, particularly when the pulse rate is reduced
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8
Q

difference between fluoroscopy and image acquisition

A

fluoro
- continuous display of images normally without recording, except LIH and store fluoro

acquisition
- discrete (spot image) or multiple images recorded in sequence
- run or cine

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9
Q

characteristics of angiographic x-ray tube

A
  • high anode rotating speed, about 10,000rpm
  • small tube angle, between 7 and 10 degrees
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10
Q

function of collimators

A
  • limits the x-ray beam to an area of the operator’s choice
  • reduces exposure to patient by reducing volume of tissue at risk
  • reduces scatter radiation at image receptor
  • dual-shape collimators
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11
Q

what are partially absorbent filters used for

A

control the bright spots produced by the lung tissue bordering the heart

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12
Q

what is high filtration

A

additional copper/ aluminium filters
- reduce skin dose by more than 70%
- preferentially absorb the lower energy photons
- some system offers variable extra filtration that is automatically set according to patient weight and angulation of C-arm

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13
Q

how does magnification mode affect radiation output

A

ABC increases patient dose with increased MAG

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14
Q

characteristics of viewing monitors

A
  • clean
  • compact
  • light
  • manoeuvrable
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15
Q

how is series images acquired

A
  • as the c-arm rotates around the patient
  • can be viewed as a cine loop, or used to reconstruct as cone-beam CT images with or without background subtracted
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16
Q

how is multiple oblique 2D view acquired

A
  • in one rotation and contrast injection, hence more info than just AP and lateral on a pathology
  • mask run done before contrast run
17
Q

contrast injected speed

A
  • consistent speed
  • faster in abdo angiography
  • slower in lymphangiography
18
Q

major components of automatic electromechanical injectors

A
  • control panel
  • pressure mechanism
  • syringes
  • warming system
19
Q

what type of imagings are there

A

injection delay
scan delay

20
Q

DSA image manipulation

A
  1. noise smoothing
  2. edge enhancement
  3. re-masking
  4. pixel shift
  5. landmarking
  6. overlay
  7. road map
  8. quantitative measurements
21
Q

what is image manipulation

A
  • an attempt to decrease visual prominence of noise
  • reduce resolution
22
Q

what is edge enhancement

A
  • increase the visibility of small structures with moderate high contrast
  • increases noise level
23
Q

what is re masking

A
  • if initial mask is inadequate because of patient motion, improper technique or other reasons, later image scan can be used as mask image
24
Q

what is pixel shift

A
  • if patient moves between the acquisition, image obtained will be registered exactly to the same pixel of image matrix
  • eliminated by re-registering of mask
  • done by shifting mask image over the series image
  • hence better superimposition of image obtained
25
Q

what is land-marking

A

adjusting the % of background on any subtracted images

26
Q

what is overlay

A
  • ordinary live fluoroscopy procedure and all background information will be seen during live fluoro
27
Q

what is road mapping

A
  • creation of roadmap mask: the post contrast frame with the highest vessel opacification is identified –> roadmap mask
  • live fluoro with subtraction
28
Q

what is quantitative measurements

A

normal left ventricular ejection fraction ranges from 55-70%