cardiac ultrasound Flashcards

1
Q

what is ultrasound of the thoracic cavity limited by

A
  • ribs (have to angle probe in intercostal spaces = small window)
  • gas (causes reflection)
  • ventilation (lung field moves with respiration)
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2
Q

what can we use thoracic ultrasound to image

A
  • heart (called echocardiography)
  • lung surface
  • pleura and pericardium
  • lymph nodes, thymus and space occyupying lesions
  • vascular structures (not limited to thorax)
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3
Q

what are the terms used to describe the windows of cardiac imaging on ultrasound (where can you place probe to get image of heart)

A

parasternal window (left or right)
- found in lateral recumbency in dogs or standing in large animals
- through ribs
subcostal window
- under the ribcage

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4
Q

what are the different axis views we use to image the heart

A
  • long axis view (from base to apex)
  • short axis view (across heart)
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5
Q

what is B-mode

A

“bright mode”
- provides a real time slice through tissues
- routinely used for qualitative assessment of function
- measurement of chamber dimensions (LA)
- more sound reflected = brighter image

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6
Q

what is M-mode

A
  • measures movement along a single plain
  • plots single plain against time
  • used to assess cardiac function (contractility and valve function)
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7
Q

what does a doppler ultrasound do

A
  • picks up the change in frequency that occurs when sound is reflected by a moving object (blood or myocardium)
  • stationary object = reflected sound is of same frequency
  • spproaching object - frequency of reflected sound is increased
  • retreating object= frequency of reflected sound is descreased

identifies velocity of blood flow (and direction)

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8
Q

what is a spectral doppler

A

describes either:
- pulsed wave doppler: records velocity from a single location
- continuous wave dopple: records velocity along a specific line (similar to M mode)

flow is proprtional to pressure difference

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9
Q

what is a colour flow doppler

A
  • uses pulse wave doppler in multiple locations
  • samples multiple areas
  • limited by aliasing, but easier to overcome with software
  • helps show things like regurgitation
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10
Q

what are indications for cardiac ultrasound

A

assessment of:
- cardiac chamber size
- myocardial pathology
- myocardial function (contractility)
- valvular function and regurgitation (using doppler)
- vascular dysfunction

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11
Q

what are the limitations of cardiac ultrasound

A
  • air (limited area of imaging depenant on cardiac notch)
  • bone ( limited imaging window and probe type, also os cordis in cattle)
  • distance (especially in large animals)
  • anatomy (forelimb may limit imaging angle)
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12
Q

what are the standardised view of cardiac ultrasound (orientation)

A
  • long and short axis views
  • mainly taken from RIGHT HAND SIDE)
  • in dogs and cats: subcostal to see aortic ejection and MV dysfunction
  • in horses left sided lets you see left atrium and aortic outflow
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13
Q

what view is this? label it

A

long axis view
Red: LV
yellow: MV
green: LA
blue: septum

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14
Q

what view is this? what structures are seen

A

short axis

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15
Q

should you be able to see the pericardium on Us

A

no, indicator of pericardial effusion

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16
Q

what can you see with ultrasound of lungs

A
  • can not visualise normal pulmonary architecture (gas filled = anechoic)
  • can identify lung surface, pleura and pleural space
  • can see lung consolidation
  • useful to identify surface pathology (especially in large animals

why?
in a normal lung, sound does not penetrate a normal aerated lung. you can only visualise smooth, freely gliding surface as there is minimal fluid

17
Q

what colour is normal blood on ultrasound

A

white swirly