Deck 14: Ultrasound Equipment Quality Assurance

Question 1

Suppose that the maximum depth of visualization using a 3.5-MHz transducer is 14.2 cm.On the previous two tests, 3 months and 6 months earlier, it was 14.4 and 14.1 cm, respectively.These variations should be interpreted as

A)just barely tolerable performance.
B)normal variations inherent in the machine.
C)excessive variations, indicating that the machine requires immediate service.
D)normal variations inherent in the measurement process.

Answer 1

D

Question 2

A measurement comparing the actual separation between two reflectors placed at different positions along the beam axis with the separation indicated on the calipers is a test of

A)axial resolution.
B)ultrasound wavelength.
C)vertical distance measurement accuracy.
D)horizontal distance measurement accuracy.

Answer 2

C

Question 3

Maximum depth of visualization tests are performed using _____ receiver gain and _____ transmit power.

A)minimum; maximum
B)maximum; minimum
C)maximum; maximum
D)minimum; minimum

Answer 3

C

Question 4

Maximum depth of visualization is often limited by

A)noise at high gain.
B)poor axial resolution.
C)too low a power setting.
D)too low a transducer frequency.

Question 5

A measure of the minimum spacing along the beam axis that still allows two reflectors to be identified is called the

A)lateral resolution.
B)axial resolution.
C)axial depth of visualization.
D)axial distance measurement accuracy.

Question 6

The maximum depth of visualization can indicate changes in

A)vertical distance measurement accuracy.
B)axial and lateral resolution.
C)slice thickness.
D)sensitivity.

Question 7

For the measurement described in question 7, the digital caliper cursors should be placed at the

A)top of the higher reflector and at the bottom of the other.
B)top of each reflector.
C)left side of one and at the right side of the other.
D)bottom of the higher reflector and at the top of the other.

Question 8

A scan is done of a uniform section in a phantom, and a vertical shadow emanates from a position on the image corresponding to the transducer surface.This is likely caused by

A)poor TGC control.
B)poor lateral gain.
C)inadequate gray-scale photography.
D)loss of signal from one or more transducer elements.

Question 9

For which of the following tests would it be acceptable for the results to vary with the transducer frequency?

A)Maximum depth of visualization
B)Axial distance measurement accuracy
C)Lateral distance measurement accuracy
D)Scan uniformity

Question 10

On the viewing monitor of a scanner, a sonographer counts 16 shades of gray in the gray-bar pattern.The hard-copy B-mode image displays only the 13 brightest gray bars.This should be interpreted as

A)normal performance.
B)too low a receiver gain.
C)inadequate photography and processing that need correction.
D)poor contrast and brightness settings on the viewing monitor.