Ultrasound Flashcards by Adrie McFarland

Frequency is a measure of _

pitch

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How is frequency of US expressed?

Hertz (Hz) or cycles per second

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Does higher or lower frequency produce a higher pitch?

Higher

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What is wavelength

Distance b/w 2 identical points on adjacent cycles

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Does a higher or lower frequency produce a shorter wavelength?

Higher

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What is amplitude

Represents the sound’s loudness

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On avg how fast does sound propegate through soft tissue?

1,540 m/sec

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On avg how fast does sound propegate through air?

343 m/sec

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On avg how fast does sound propegate through bone

3,000-5,000 m/sec

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What is the piezoelectric materieal that modern ultrasounds typically use?

Zirconate Titanate

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What does hyperechoic mean on US?

Looks bright

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What does anechoic mean on US?

Looks very dark

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What does hypoechoic mean on US?

Looks less bright than hyperechoic

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Do dense tissues like bone have high or low amplitude? High or low impedence?

high
high

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Do hypoechoic structures have high or low amplitude? Higher or lower impedence?

Low amplitude
Low impedence

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What kind of structures appear anechoic?

Vascular structures, cysts, ascites

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Distal peripheral nerves are usually white. How do more central nerves appear?

Darker. Can be confused with vasculature but wont pulsate or compress

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What are the 3 zones of the ultrasound beam?

Focal zone: Region where the beam is narrowest
Near zone: Region b/w the transducer and the focal zone
Far zone: Region beyond the focal zone

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Which region is resolution the best? Second best?

Focal zone

Near zone

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What is attenuation?

When signal travels through the medium and some of the signals do not make it back to the probe.

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What is the frequency range for high frequency probe

> 10 MHz

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What is the frequency range for medium frequency?

5-10 MHz

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What is the frequency range for low frequency?

< 5 MHz

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Imaging depth for high frequency?

< 3 cm below skin

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Imaging depth for medium frequency?

3-6 cm below skin

Imaging depth for low frequency?

> 6 cm below skin

What does the B in B mode stand for?

Brightness

What does the M in M mode stand for?

Motion

What color is a + doppler shift?

Red

What color is a negative doppler shift?

Blue

To detect whether flow is venous or arterial, how should probe be placed to get a clear picture? (carotid and ij)

Less than 90 degrees relative to the direction of the carotid blood flow and greater than 90 degrees relative to the direction of the IJ blood flow

When viewing the short axis view, the orientation marker points towards the patients anatomic right or left?

Right

When viewing the long axis of the patients body, the orientation marker points towards the patients head or foot?

Head

Left is lateral for a regular probe but which way is lateral for a cardiac probe?

Opposite

Sharpest ultrasound image will occur with the ultrasound beam meeting a structure at how many degrees?

Tilt vs rocking the probe.

Tilt = fanning Rock = side to side

What is acoustic enhancement

Opposite of shadow artifact. Brightness under fluid collection

What is bayoneting

needle appears to bend as it penetrates a tissue boundary

What are the 3 standard imaging windows for cardiac POCUS?

Parasternal Apical Subcostal

There are three standard imaging windows, what are the 5 core views within those?

PLAX PSAX A4CH Subcostal 4CH Subcostal IVC

How should patient be positioned for PLAX?

LLD (brings the heart closer to the anterior chest and reduces the influence of lung artifact), or supine.

What kind of probe do you use for PLAX and where do you place it?

Phased array, just left of the sternum at the third or fourth ICS

What does PLAX stand for?

Parasternal long-axis

Where should orientation marker point?

Towards the patients right shoulder

Which structures can be seen with PLAX?

LA LV Mitral valve Aortic valve Aorta Pericardium

What does PLAX give you information about?

LV function LV hypertrophy Mitral and aortic valve lesions Pericardial effusion

PLAX is the equivalent to which TEE view?

Midesophageal long-axis

What does PSAX stand for?

Parasternal short axis

What is the difference in probe orientation for PSAX compared to PLAX?

Keep oriented the same for PLAX but then rotate the transducer 90 degrees clockwise so the orientation marker points to the patients left shoulder

What structures are being assessed with PSAX?

LV RV Pericardium

PSAX is equivalent to which TEE view?

Transgastric short axis

What does A4CH stand for?

Apical 4-chamber

Positioning for Apical 4 chamber

LLD

Where does transducer get placed for A4CH?

Point of maximum impulse For males: Inferolateral to the left nipple For females: under the inferolateral quadrant of the left breast in women

What is transducers orientation for A4CH

Point the transducers orientation marker to the patients left side with the US beam pointing towards the patients right shoulder

What structures are seen with A4CH?

RA RV LA LV AV valves Pericardium

What is the equivalent view of A4CH on TEE?

Midesophageal 4 chamber

What does Subcostal 4CH stand for?

Subcostal 4 chamber

How should the patient be positioned for subcostal 4CH?

Supide

Where should the transducer be positioned for Subcostal 4 chamber?

Midline just inferior to the xiphoid process

Where should the transducers orientation marker point for Subcostal 4CH?

Patient's left side

What structures are assessed using the Subcostal 4CH?

RA RV LA LV AV valves Pericardial space

Function of which ventricle is being assessed using the Subcostal 4CH view?

TEE equivalent view to Subcostal 4CH?

Midesophageal 4 chamber

How should transducer be placed for the Subcostal IVC view?

From subcostal 4 chamber view, rotate the transducer 90 degrees From here, you can tilt the beam in the posterior direction

Structures being assessed using subcostal IVC view

IVC RA Liver

What information does Subcostal IVC view give you?

Volume status. IVC collaplse suggests hypovolemia

Lung US is useful for diagnosing:

Pneumothorax Endobronchial intubation

What is the bat sign on US and how do you get a view of it?

Observe the 2 hyperechoic ribs, and you will see the pleura as a hyperechoic line in the intercostal space just below the rib line. *The pattern of the 2 ribs and the pleural line is called the bat sign, where the ribs form the wings and the pleural line forms the body

What does lung sliding look like? Is that normal?

Lung sliding is seen throughout the respiratory cycle. It looks shimmering in quality. This sign confirms the parietal and visceral pleura are in apposition and that there isn't any air or excess fluid between the plurae.

What does the absence of lung sliding mean?

Pneumothorax Endobronchial intubation

Are A lines horizontal or vertical?

Horizontal

Are B lines horizontal or vertical?

Vertical

What are A lines on the lung US due to?

Horizontal lines that result from reverberation artifact due to the pleura acting a strong reflector

What are B lines on the lung US due to?

Can be a normal finding, but they can also suggest pathology such as pulmonary edema

What is the primary anatomy of interest with gastric US?

Antrum

What position should the pt be in for gastric US?

Right Lateral Decub *This allows air to rise to the top of the stomach while gravity moves gastric contents in the direction of the pylorus to fill the antrum

What is the problem with performing gastric US in the supine position?

Will likely underestimate the volume of gastric contents

Which probe should you use for stomach US and how should it be positioned?

Curvilinear Placed midline just below the xiphoid process, with the transducers orientation indicator pointing cephalad

What will empty stomach look like on stomach US?

Flat or like a small oval, which is sometimes referred to as a "bulls eye"

What will clear liquids look like on stomach US?

Antrum will look round and distended. Clear liquids will be anechoic

What color would any non-clear liquid appear in the antrum on gastric US?

Hyperechoic

How do we calculate the volume of clear gastric fluid?

Measure the CSA of the antrum at the level of the aorta with the patient in the right lateral decub position. **The CSA value should be the avg of 3 seperate measurements to avoid error

When there is clear fluid in the antrum seen on US, what volume is considered grade 1 low risk?

< 1.5 mL/kg

When there is clear fluid in the antrum seen on US, what volume is considered grade 2 high risk?

> 1.5 mL/kg

Ultrasound Flashcards

(85 cards)