Artifacts

Question 1

Reverberation artifact cause

Answer 1

multiple echoes from sound wave bouncing between 2 reflectors

Question 2

Refraction artifact

Answer 2

objects misplaced laterally

Question 3

Axial resolution primarily affected by

Answer 3

Frequency

Question 4

Lateral resolution primarily affected by

Answer 4

Beam width - affected by focal zone

Question 5

Stitch artifact cause

Answer 5

Heart moving between cardiac cycles (eg breathing)

Question 6

Velocity error artifact

Answer 6

Ultrasound assumes sound propagates through all structures at 1540m/sec so objects distorted if velocity differs

Question 7

Near field reflection artifact

Answer 7

Additional images formed by strong acoustic signals close to transducer (eg apex obscured to rule out thrombus)

Question 8

Sidelobe artifact

Answer 8

Generally arcuate

From strong reflectors outside beam generating echoes

Question 9

Range ambiguity artifact cause and correction

Answer 9

Caused by structure distal to image sending back echo

Correct by changing depth

Question 10

Enhancement artifact

Answer 10

brighter structures behind fluid filled structures