Artifacts

Question 1

Normal, caused by sound waves bouncing off of super reflective diaphragm

Answer 1

Mirror image artifact

Question 2

Also called side lobe artifact

occur where side lobes reflect sound from a strong reflector that is outside of the central beam, and where the echoes are displayed as if they originated from within the central beam 

Answer 2

Edge artifact 

Question 3

increased echoes deep to structures that transmit sound exceptionally well such as the gallbladder, urinary bladder, and other fluid filled structures

The time gain compensation (TGC) overcompensates through the fluid-filled structure causing deeper tissues to be brighter. Simply it is seen as increased echogenicity (whiteness) posterior to the cystic area

Answer 3

Posterior acoustic enhancement 

Question 4

apparent lack of signal deep to an imaged tissue interface, due to all (or nearly all) of the transmitted sound wave being being reflected back to the transducer or absorbed by the tissue

commonly occurs when an area of interest contains a high Z/solid tissue (e.g. calcified gallstone or bone) or at an interface with high acoustic impedance mismatch (e.g. soft tissue/air).

Answer 4

Posterior acoustic shadowing 

Question 5

When the ultrasound beam is incident on a fibrillar structure such as a tendon or a ligament, the organized fibrils may reflect a majority of the insonating sound beam in a direction away from the transducer. When this occurs, the transducer does not receive the returning echo and assumes that the insonated area should be hypoechoic

Answer 5

Anisotropy 

Question 6

occur when two interfaces with high acoustic impedance bounce the ultrasound waves between them. A common example is the “A-lines” visualized on thoracic ultrasound. A-lines are the reverberated ultrasound waves that have bounced between the parietal and visceral pleura.

Answer 6

Reverberation artifact 

Question 7

The source of ring-down artifact is a small pocket of fluid trapped by surrounding air bubbles. Ultrasound waves hit a pocket of trapped fluid, the sound waves resonate within the fluid, and a continuous sound wave is transmitted back to the transducer. The resonant vibrations detected by the ultrasound transducer are displayed as bright vertical lines extending deep to the trapped fluid.

Answer 7

Ring down artifact 

Question 8

produced when sound waves are reflected between two highly reflective surfaces in very close proximity. Comet tails classically appear as bright vertical lines with a tapering shape. After several reflections, the amplitude of returning echoes is decreased, which is displayed as narrowing of the lines compared to the original echo.

Answer 8

Comet tail artifact 

Question 9

seen with color flow Doppler ultrasound 1. It occurs as a focus of alternating colors on Doppler signal behind a reflective object (such as a calculus), which gives the appearance of turbulent blood flow

Answer 9

Twinkle artifact 

Question 10

Which of the following statements regarding lung-imaging artifacts is correct?
A. The lung pulse indicates the presence of a pneumothorax.
B. The sliding-lung sign indicates the presence of a pneumothorax.
C. The absence of lung sliding confirms the presence of a pneumothorax.
D. Lung sliding is typically absent in the presence of a pneumothorax.
E. A-line artifact is characterized by vertical, anechoic lines on the ultrasound screen.

Answer 10

D. Lung sliding is typically absent in the presence of a pneumothorax

Question 11

T/F: A-line artifacts are hyperechoic, horizontal lines that appear at regular intervals deep to the pleural line and are a type of reverberation artifact

Answer 11

True

Question 12

T/F: B-line artifact always indicates the presence of lung pathology

Answer 12

False. 1–3 B lines per rib space can be normal.

Question 13

What can the absence of a lines indicate in lung ultrasound? 

Answer 13

Something has changed in the lung replacing air with substances that transmit sound waves:
-Blood
-Interstitial or alveolar edema
-Infection
-Contusion
-Tumor

Question 14

List three findings that indicate normal lung sliding? 

Answer 14

1. Shimmering pleura
2. Comet tails (short)
3. M mode; seashore sign

Question 15

Describe how the lines are different from comet tails. 

Answer 15

B line Characteristics:
1. Well defined hyperechoic vertical lines
2. One or more per field is 2- significant
3. Originate at pleural interface
4. Extend ray like to bottom of screen( *18cm)12
5. Efface A lines
6. Move in synchrony with lung sliding
7. Presence excludes presence of pneumothorax
*8. Positive zone > 3 B lines
*9. Pulmonary edema > 2 zones /side

**Means there is fluid in the lung

Question 16

True or false? The presence of B lines rules out pneumothorax.

Answer 16

True. If there are any B lines present, a pneumothorax is not possible.