High Yield PTEeXAM Review Part 6-8 Flashcards

1
Q

What is a normal DF range?

A
  1. 2 - 0.5%
    i. e. Listening 99.8% of time
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2
Q

What is duty factor determined by?

A

Sound source only

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3
Q

What is duty factor inversely related to?

A

Depth

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4
Q

What is the Duty Factor % equation?

A

Pulse Duration* / *Pulse Repetition Period

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5
Q

How does the Pulse repetition frequency change with shallow vs. deep images?

A

Shallow = Higher PRF

Deep = Lower PRF

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6
Q

How does duty factor change with depth?

A
Shallow = Higher DF
Deeper = Lower DF
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7
Q

What is the typical value of a pulse duration?

A

0.5 - 3.0 microseconds

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8
Q

What is the typical pulse repetition period?

A

0.1 - 1.0 ms

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9
Q

What is the typical pulse repetition frequency?

A

1 - 10 kHz

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10
Q

What is the typical spatial pulse length?

A

0.1 - 1.0 mm

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11
Q

During PWD echo, the frequency of the emitted beam is determined by what two things?

A
  1. Thickness of piezoelectric crystals
  2. Speed of propagation of sound in the crystals
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12
Q

What is the equation for resonant frequency?

A

Velocity of sound in crystal* / [*2 * thickness of the crystal]

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13
Q

Which ASD is more common:

Superior* sinus venosus VSD or an *inferior sinus venousus VSD?

A

superior = More common

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14
Q

What is a superior sinus venousus ASD associated with?

A

Anomalous Venous Drainage of the RUPV

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15
Q

What is a inferior sinus venousus ASD associated with?

A

Anomalous pulmonary venous drainage of a scimitar vein

Scimitar syndrome

Drains from hypoplastic RLL of the lung

Aortopulmonary collaterals

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16
Q

What 3 things does Scimitar syndrome have?

A
  1. Inferior Sinus venous ASD
  2. RLL hypoplastic lung with scimitar vein draining into the IVC
  3. Aortopulmonary collaterals going to RLL of the lung
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17
Q

What is ostium primum ASD associataed with?

A

Trisomy 21

Near AV valves (Cleft leaflets)

  • Septal TV
  • Anterior MV
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18
Q

What is a partial AV canal?

A

Primum ASD with No VSD

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19
Q

What is a transitional AV canal?

A

Primum ASD with restrictive inlet VSD

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20
Q

What is a complete AV canal?

A

Primum ASD + Non-restrictive inlet VSD

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21
Q

An ostium secundum ASD is a defect in what structure?

A

Defect in septum primum (Area of fossa ovalis)

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22
Q

What is ostium secundum ASD associated with?

A

Mitral valve prolapse

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23
Q

Transmitral Flow Propagation Velocity:

load dependent or load independent?

A

Load dependent

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24
Q

What does the backing material of the echo probe function to do?

A

Shortens the pulse duration

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25
Q

The matching layer is how thick in comparison to the wavelength?

A

About 1/4 length of the wavelength

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26
Q

The piezoelectric crystals are how thick compared to the wavelength?

A

About 1/2 the wavelength

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27
Q

What is the benefit of a short pulse duration?

A

Improved axial resolution

Why? Axial resolution = 1/2 * Spatial Pulse Length

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28
Q

How does backing material affect bandwidth?

A

Increases bandwidth

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29
Q

How does increased bandwidth affect Q factor?

A

Q = RF / Bandwidth

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30
Q

How does frequency affect penetration?

A

Increased frequency = Increased penetration (More attenuation)

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31
Q

How does a decreased frequency affect axial resolution?

A

Worsens it

Why? worsen frequency = Longer spataial pulse length)

32
Q

What does decreased frequency do to the focal length?

A

Shorter focal length

NL (Near field length) = r2 / Wavelengths

33
Q

What is the doppler velocity index for the aortic valve?

A

V LVOT / V Aortic Valve

34
Q

What are the values for dimensionless index for:
No Aortic Stenosis

A

V LVOT / V Aortic Valve

Normal 1.0 or above

35
Q

What are the values for dimensionless index for:
Mild Aortic Stenosis

A

>0.5

V LVOT / V Aortic Valve

36
Q

What are the values for dimensionless index for:
Moderate Aortic Stenosis

A

0.25 - 0.5

V LVOT / V Aortic Valve

37
Q

What are the values for dimensionless index for:
Severe Aortic Stenosis

A

<0.25

V LVOT / V Aortic Valve

38
Q

What is acceleration time for prosthetic acceleration?

What is normal vs. stenotic?

A

AT >100 ms = Stenotic

AT <100ms = Normal

39
Q

How would acceleration time and ejection time affect your determination of stenosis aortic valve prosthesis?

A

Acceleration Time / Ejection time >0.4 = Stenosis

40
Q

What peak velocity is associated with prosthetic valve aortic stenosis?

A

> 4 m/s

41
Q

What mean gradient is associated with prosthetic valve aortic stenosis?

A

> 35 mmHg

42
Q

What effective orifice area is associated with prosthetic valve aortic stenosis?

A

< 0.8 cm2

43
Q

List 8 risk factors (measurements) for SAM after MVR?

A

1. End diastolic diameter < 45 mm

2. C-sept distance >2.5 cm (Distance from coaptation point to closest part of the ventricular septum)

3. Narrow LVOT (< 20 mm)

4. Mitral-Aortic angle <120 degrees (Angle formed by intersection of MV annulus and AV annulus

  1. AL / PL < 1.3 (anterior mitral leaftlet to posterior leaflet ratio = anterior annulus to coaptation point / posterior annulus to coaptation point)
  2. Basal septal hypertrophy > 15 mm
  3. Anterior mitral leaflet length > 20 mm (End-diastole from ME 5 chamber view)
  4. Posterior mitral length > 15 mm (End - diastole from ME 5 chamber a long posterior leaflet “pushes” the coaptation point towards LVOT)
44
Q

How does a decrease in beam width affect lateral resolution?

A

Decrease in beam width = Improved lateral resolution

45
Q

What resolution types is most important to least important?

Hint: Include the mneumonic

A

ALE = Mneumonic (Like the beer)

Axial > Lateral > Elevational

46
Q

What is the definition of wavelength?

A

Distance / Length of a single cycle

47
Q

What is the spatial pulse length?

A

Length of the entire pulse

48
Q

What is period?

A

TIme it takes to complete a single cycle

49
Q

What is frequency on a wavelength?

A

inverse of period

(# of cycles / second)

50
Q

What is pulse duration?

A

Time it takes to complete a single pulse

Analogous to the spatlal pulse length (Distance)

51
Q

What is the pulse repetition period?

A

TIme for one pulse to send and then listen

52
Q

What is the pulse repetition frequency?

A

Inverse of the pulse repetition period

of pulses per second

53
Q

What is the nyquist limit equation?

A

1/2 of the Pulse Repetition Frequency

54
Q

What resolution is important for the pulse repetition frequency?

A

Temporal Resolution

55
Q

What is power?

A

Rate of energy transfer

AKA
Rate at which work is performed

56
Q

What is intensity?

A

Power / Area

57
Q

During CWD, the frequency of the U/S beam is determined by:

A

Frequency of the electrical current applied to the crystal

58
Q

What are the indications for surgery or alcohol ablation therapy for HOCM?

A
  1. LVOT obstruction with resting peak instantaneous gradient > 30 mmHg
  2. SAD (Syncope, Angina, Dyspneaa) symptoms impairing life
  3. Persistent symptoms despite medical therapy
59
Q

What wall thickness on echo would warrant alcohol ablation or septal myectomy with HOCM?

A

> 30 mm

60
Q

What global strain would warrant intervention with HOCM?

A

> -18 (More negative than -18

61
Q

What E / Vp ratio predicts PCWP >15 mmHg in patients with decreased LVEF?

A

> 2.5

62
Q

The Annular focusing technique refers to?

A

Focusing in all directions

63
Q

What occurs when the wavelength is much larger than the reflector?

A

Raleigh Scattering

64
Q

What is attenution?

A

Decrease in intensity / power / amplitude

65
Q

How does attenuation relate to frequency?

A

Higher frequency = Increased attenuation

66
Q

What is specular reflection?

A

Reflection off of a smooth surface-only in one direction

67
Q

What is diffucse reflection?

A

Reflection off an irregulra surface (More than one direction)

  • Interfaces at suboptimla angles to the sound beaama can still produce reflections
68
Q

What tissue has the most diffuse reflection?

A

Lung

  • Sound wave is bigger than the tissue
69
Q

If the image is too dark, what do you increase?

A

Gain

70
Q

If the image is too bright, what do you decrease?

A

Decrease Power First

71
Q

What does an increased power do to lateral resolution?

A

Degradation of lateral resolution

72
Q

Formation of Grating Lobes leads to….

A

deterioration of lateral resolution

73
Q

A reduction in spataion pulse length will do what to axial resolution?

A

Improve it

Formula: 1/2 SPL = Axial resolution

74
Q

How would a decreased beam height affect elevational resolution?

A

Decreased beam height = Improved elevational resolution

75
Q

What body tissue has the highest propagation velocity for ultrasound?

A

Bone

76
Q

How do low frequency transducers affect:

Attenuation?
Penetration?

A

Low freq

  1. Decreased attenuataion
  2. Increased depth of penetration